Merge pull request 'fix(github): consolidate review.go and identity.go into reviews.go (#116)' (#119) from review-bot-issue-116 into feature/github-support

Reviewed-on: #119
Reviewed-by: Aaron Weiker <aaron@weiker.org>
Reviewed-by: security-review-bot <10+security-review-bot@noreply.gitea.weiker.me>

.gitea/actions/review/action.yml

@@ -1,6 +1,7 @@
 # This composite action is designed for Gitea Actions runners.
 # Gitea Actions supports GitHub Actions syntax including $GITHUB_OUTPUT,
 # actions/cache, and actions/checkout.
+# Requirements: python3, sha256sum, curl (all present on ubuntu-* runners).
 name: 'AI Code Review'
 description: 'Run AI-powered code review on a pull request using review-bot'
 
@@ -25,30 +26,60 @@ inputs:
     required: false
     default: ''
   llm-base-url:
-    description: 'OpenAI-compatible LLM API base URL'
-    required: true
+    description: 'OpenAI-compatible LLM API base URL (not required for aicore provider)'
+    required: false
+    default: ''
   llm-api-key:
-    description: 'LLM API key'
-    required: true
+    description: 'LLM API key (not required for aicore provider)'
+    required: false
+    default: ''
   llm-model:
     description: 'LLM model name'
     required: true
+  llm-provider:
+    description: 'LLM API provider: openai, anthropic, or aicore (default openai)'
+    required: false
+    default: 'openai'
+  aicore-client-id:
+    description: 'SAP AI Core client ID (required for aicore provider)'
+    required: false
+    default: ''
+  aicore-client-secret:
+    description: 'SAP AI Core client secret (required for aicore provider)'
+    required: false
+    default: ''
+  aicore-auth-url:
+    description: 'SAP AI Core authentication URL (required for aicore provider)'
+    required: false
+    default: ''
+  aicore-api-url:
+    description: 'SAP AI Core API URL (required for aicore provider)'
+    required: false
+    default: ''
+  aicore-resource-group:
+    description: 'SAP AI Core resource group (default: default)'
+    required: false
+    default: 'default'
   conventions-file:
     description: 'Path to conventions file in the repo (e.g. CLAUDE.md)'
     required: false
     default: ''
   patterns-repo:
-    description: 'Repo with language patterns (e.g. rodin/elixir-patterns)'
+    description: 'Comma-separated repos with language patterns (e.g. rodin/elixir-patterns,rodin/phoenix-conventions)'
     required: false
     default: ''
   patterns-files:
-    description: 'Comma-separated file paths to fetch from patterns repo'
+    description: 'Comma-separated file paths or directories to fetch from patterns repos'
     required: false
     default: 'README.md'
   temperature:
     description: 'LLM temperature (0 = server default)'
     required: false
     default: '0'
+  timeout:
+    description: 'LLM request timeout in seconds (default 300)'
+    required: false
+    default: '300'
   version:
     description: 'review-bot version to install (e.g. v0.1.0, defaults to latest)'
     required: false
@@ -57,6 +88,22 @@ inputs:
     description: 'Print review to stdout instead of posting'
     required: false
     default: 'false'
+  update-existing:
+    description: 'Delete previous review from same bot after posting new one. Accepts: true/1/yes or false/0/no (default true)'
+    required: false
+    default: 'true'
+  system-prompt-file:
+    description: 'Local file with additional system prompt instructions (e.g. security review focus)'
+    required: false
+    default: ''
+  persona:
+    description: 'Built-in persona name (security, architect, docs)'
+    required: false
+    default: ''
+  persona-file:
+    description: 'Path to custom persona JSON file'
+    required: false
+    default: ''
 
 runs:
   using: 'composite'
@@ -134,6 +181,17 @@ runs:
         PATTERNS_REPO: ${{ inputs.patterns-repo }}
         PATTERNS_FILES: ${{ inputs.patterns-files }}
         LLM_TEMPERATURE: ${{ inputs.temperature }}
+        LLM_TIMEOUT: ${{ inputs.timeout }}
+        LLM_PROVIDER: ${{ inputs.llm-provider }}
+        UPDATE_EXISTING: ${{ inputs.update-existing }}
+        SYSTEM_PROMPT_FILE: ${{ inputs.system-prompt-file }}
+        PERSONA: ${{ inputs.persona }}
+        PERSONA_FILE: ${{ inputs.persona-file }}
+        AICORE_CLIENT_ID: ${{ inputs.aicore-client-id }}
+        AICORE_CLIENT_SECRET: ${{ inputs.aicore-client-secret }}
+        AICORE_AUTH_URL: ${{ inputs.aicore-auth-url }}
+        AICORE_API_URL: ${{ inputs.aicore-api-url }}
+        AICORE_RESOURCE_GROUP: ${{ inputs.aicore-resource-group }}
       run: |
         ARGS=""
         if [ "${{ inputs.dry-run }}" = "true" ]; then

.gitea/workflows/ci.yml

@@ -18,7 +18,10 @@ jobs:
       - run: go vet ./...
       - run: go build -o review-bot ./cmd/review-bot
 
-  # Self-review: builds from source since we're pre-release
+  # Self-review using native SAP AI Core provider
+  # Models must match SAP AI Core deployments
+  # Available models: gpt-5, anthropic--claude-4.6-sonnet, anthropic--claude-4.6-opus
+  # Removed gpt-4.1, gpt-5-mini, gpt-4.1-mini - not deployed on AI Core
   review:
     runs-on: ubuntu-24.04
     if: github.event_name == 'pull_request'
@@ -28,10 +31,16 @@ jobs:
         include:
           - name: sonnet
             token_secret: SONNET_REVIEW_TOKEN
-            model: gpt-5
+            model: anthropic--claude-4.6-sonnet
           - name: gpt
             token_secret: GPT_REVIEW_TOKEN
-            model: gpt-5-mini
+            model: gpt-5
+          - name: security
+            token_secret: SECURITY_REVIEW_TOKEN
+            model: gpt-5
+            patterns_repo: rodin/security-patterns
+            patterns_files: "."
+            system_prompt_file: SECURITY_REVIEW.md
     steps:
       - uses: actions/checkout@v4
       - uses: actions/setup-go@v5
@@ -44,10 +53,17 @@ jobs:
           GITEA_REPO: ${{ github.repository }}
           PR_NUMBER: ${{ github.event.pull_request.number }}
           REVIEWER_TOKEN: ${{ secrets[matrix.token_secret] }}
-          LLM_BASE_URL: ${{ secrets.LLM_BASE_URL }}
-          LLM_API_KEY: ${{ secrets.LLM_API_KEY }}
+          REVIEWER_NAME: ${{ matrix.name }}
+          LLM_PROVIDER: aicore
           LLM_MODEL: ${{ matrix.model }}
+          AICORE_CLIENT_ID: ${{ secrets.AICORE_CLIENT_ID }}
+          AICORE_CLIENT_SECRET: ${{ secrets.AICORE_CLIENT_SECRET }}
+          AICORE_AUTH_URL: ${{ secrets.AICORE_AUTH_URL }}
+          AICORE_API_URL: ${{ secrets.AICORE_API_URL }}
+          AICORE_RESOURCE_GROUP: ${{ secrets.AICORE_RESOURCE_GROUP }}
           CONVENTIONS_FILE: "CONVENTIONS.md"
-          PATTERNS_REPO: "rodin/go-patterns"
-          PATTERNS_FILES: "README.md,docs/"
+          PATTERNS_REPO: ${{ matrix.patterns_repo || 'rodin/go-patterns' }}
+          PATTERNS_FILES: ${{ matrix.patterns_files || 'README.md,patterns/' }}
+          LLM_TIMEOUT: "600"
+          SYSTEM_PROMPT_FILE: ${{ matrix.system_prompt_file }}
         run: ./review-bot

.gitea/workflows/pr-ready-gate.yml

@@ -0,0 +1,38 @@
+name: PR Ready Gate
+
+on:
+  pull_request:
+    types: [synchronize]
+
+jobs:
+  clear-labels:
+    runs-on: ubuntu-24.04
+    # Always run - curl commands are safe if labels don't exist
+    steps:
+      - name: Remove ready and self-reviewed labels, reassign to author
+        env:
+          GITEA_TOKEN: ${{ secrets.RODIN_TOKEN }}
+        run: |
+          PR_NUMBER=${{ github.event.pull_request.number }}
+          AUTHOR=${{ github.event.pull_request.user.login }}
+          READY_LABEL_ID=38
+          SELF_REVIEWED_LABEL_ID=37
+          
+          # Remove ready label if present
+          curl -sS -X DELETE \
+            -H "Authorization: token $GITEA_TOKEN" \
+            "https://gitea.weiker.me/api/v1/repos/${{ github.repository }}/issues/${PR_NUMBER}/labels/${READY_LABEL_ID}" || true
+          
+          # Remove self-reviewed label if present
+          curl -sS -X DELETE \
+            -H "Authorization: token $GITEA_TOKEN" \
+            "https://gitea.weiker.me/api/v1/repos/${{ github.repository }}/issues/${PR_NUMBER}/labels/${SELF_REVIEWED_LABEL_ID}" || true
+          
+          # Reassign to author
+          curl -sS -X PATCH \
+            -H "Authorization: token $GITEA_TOKEN" \
+            -H "Content-Type: application/json" \
+            -d "{\"assignees\": [\"${AUTHOR}\"]}" \
+            "https://gitea.weiker.me/api/v1/repos/${{ github.repository }}/pulls/${PR_NUMBER}"
+          
+          echo "Cleared ready/self-reviewed labels and reassigned PR #${PR_NUMBER} to ${AUTHOR}"

.gitea/workflows/release.yml

@@ -16,7 +16,9 @@ jobs:
           go-version: '1.26'
 
       - name: Run tests
-        run: go test ./...
+        run: |
+          go vet ./...
+          go test ./...
 
       - name: Build binaries
         run: |
@@ -67,14 +69,28 @@ jobs:
 
           echo "Release ID: ${RELEASE_ID}"
 
-          # Upload each asset
+          # Upload each asset (idempotent: delete existing asset with same name first)
           for file in dist/*; do
             filename=$(basename "$file")
             echo "Uploading ${filename}..."
+
+            # Check if asset already exists and delete it
+            EXISTING_ID=$(export ASSET_NAME="${filename}"; curl -sS \
+              -H "Authorization: token ${GITEA_TOKEN}" \
+              "${GITEA_URL}/api/v1/repos/${REPO}/releases/${RELEASE_ID}/assets" \
+              | python3 -c "import json,sys,os; name=os.environ['ASSET_NAME']; assets=json.load(sys.stdin); print(next((str(a['id']) for a in assets if a['name']==name),''))" 2>/dev/null)
+
+            if [ -n "$EXISTING_ID" ]; then
+              echo "  Asset ${filename} already exists (id=${EXISTING_ID}), deleting..."
+              curl -sSf -X DELETE \
+                -H "Authorization: token ${GITEA_TOKEN}" \
+                "${GITEA_URL}/api/v1/repos/${REPO}/releases/${RELEASE_ID}/assets/${EXISTING_ID}"
+            fi
+
             curl -sSf -X POST \
               -H "Authorization: token ${GITEA_TOKEN}" \
               -H "Content-Type: application/octet-stream" \
-              "${GITEA_URL}/api/v1/repos/${REPO}/releases/${RELEASE_ID}/assets?name=${filename}" \
+              "${GITEA_URL}/api/v1/repos/${REPO}/releases/${RELEASE_ID}/assets?name=$(printf '%s' "${filename}" | jq -sRr @uri)" \
               --data-binary "@${file}"
           done
 

.github/actions/review/action.yml

@@ -0,0 +1,200 @@
+# This composite action is designed for Gitea Actions runners.
+# Gitea Actions supports GitHub Actions syntax including $GITHUB_OUTPUT,
+# actions/cache, and actions/checkout.
+# Requirements: python3, sha256sum, curl (all present on ubuntu-* runners).
+name: 'AI Code Review'
+description: 'Run AI-powered code review on a pull request using review-bot'
+
+inputs:
+  gitea-url:
+    description: 'Gitea instance URL (defaults to server_url)'
+    required: false
+    default: ''
+  repo:
+    description: 'Repository (owner/name, defaults to current)'
+    required: false
+    default: ''
+  pr-number:
+    description: 'Pull request number (defaults to current PR)'
+    required: false
+    default: ''
+  reviewer-token:
+    description: 'Gitea token for posting the review'
+    required: true
+  reviewer-name:
+    description: 'Display name for the reviewer'
+    required: false
+    default: ''
+  llm-base-url:
+    description: 'OpenAI-compatible LLM API base URL (not required for aicore provider)'
+    required: false
+    default: ''
+  llm-api-key:
+    description: 'LLM API key (not required for aicore provider)'
+    required: false
+    default: ''
+  llm-model:
+    description: 'LLM model name'
+    required: true
+  llm-provider:
+    description: 'LLM API provider: openai, anthropic, or aicore (default openai)'
+    required: false
+    default: 'openai'
+  aicore-client-id:
+    description: 'SAP AI Core client ID (required for aicore provider)'
+    required: false
+    default: ''
+  aicore-client-secret:
+    description: 'SAP AI Core client secret (required for aicore provider)'
+    required: false
+    default: ''
+  aicore-auth-url:
+    description: 'SAP AI Core authentication URL (required for aicore provider)'
+    required: false
+    default: ''
+  aicore-api-url:
+    description: 'SAP AI Core API URL (required for aicore provider)'
+    required: false
+    default: ''
+  aicore-resource-group:
+    description: 'SAP AI Core resource group (default: default)'
+    required: false
+    default: 'default'
+  conventions-file:
+    description: 'Path to conventions file in the repo (e.g. CLAUDE.md)'
+    required: false
+    default: ''
+  patterns-repo:
+    description: 'Comma-separated repos with language patterns (e.g. rodin/elixir-patterns,rodin/phoenix-conventions)'
+    required: false
+    default: ''
+  patterns-files:
+    description: 'Comma-separated file paths or directories to fetch from patterns repos'
+    required: false
+    default: 'README.md'
+  temperature:
+    description: 'LLM temperature (0 = server default)'
+    required: false
+    default: '0'
+  timeout:
+    description: 'LLM request timeout in seconds (default 300)'
+    required: false
+    default: '300'
+  version:
+    description: 'review-bot version to install (e.g. v0.1.0, defaults to latest)'
+    required: false
+    default: 'latest'
+  dry-run:
+    description: 'Print review to stdout instead of posting'
+    required: false
+    default: 'false'
+  update-existing:
+    description: 'Delete previous review from same bot after posting new one. Accepts: true/1/yes or false/0/no (default true)'
+    required: false
+    default: 'true'
+  system-prompt-file:
+    description: 'Local file with additional system prompt instructions (e.g. security review focus)'
+    required: false
+    default: ''
+  persona:
+    description: 'Built-in persona name (security, architect, docs)'
+    required: false
+    default: ''
+  persona-file:
+    description: 'Path to custom persona JSON file'
+    required: false
+    default: ''
+
+runs:
+  using: 'composite'
+  steps:
+    - name: Determine version
+      id: version
+      shell: bash
+      run: |
+        GITEA_URL="${{ inputs.gitea-url || github.server_url }}"
+        REPO="${{ inputs.repo || 'rodin/review-bot' }}"
+        if [ "${{ inputs.version }}" = "latest" ]; then
+          VERSION=$(curl -sSf "${GITEA_URL}/api/v1/repos/${REPO}/releases?limit=1" \
+            | python3 -c "import sys, json; releases = json.load(sys.stdin); print(releases[0]['tag_name'] if releases else '')")
+          if [ -z "$VERSION" ]; then
+            echo "Failed to determine latest version" >&2
+            exit 1
+          fi
+        else
+          VERSION="${{ inputs.version }}"
+        fi
+        echo "version=${VERSION}" >> "$GITHUB_OUTPUT"
+
+    - name: Cache review-bot binary
+      id: cache
+      uses: actions/cache@v4
+      with:
+        path: ${{ runner.temp }}/review-bot
+        key: review-bot-linux-amd64-${{ steps.version.outputs.version }}
+
+    - name: Install review-bot
+      if: steps.cache.outputs.cache-hit != 'true'
+      shell: bash
+      run: |
+        GITEA_URL="${{ inputs.gitea-url || github.server_url }}"
+        REPO="${{ inputs.repo || 'rodin/review-bot' }}"
+        VERSION="${{ steps.version.outputs.version }}"
+        BINARY="review-bot-linux-amd64"
+
+        curl -sSfL "${GITEA_URL}/${REPO}/releases/download/${VERSION}/${BINARY}" \
+          -o "${{ runner.temp }}/review-bot"
+        curl -sSfL "${GITEA_URL}/${REPO}/releases/download/${VERSION}/checksums.txt" \
+          -o "${{ runner.temp }}/checksums.txt"
+
+        # Verify SHA-256 checksum
+        cd "${{ runner.temp }}"
+        EXPECTED=$(grep "${BINARY}" checksums.txt | awk '{print $1}')
+        ACTUAL=$(sha256sum review-bot | awk '{print $1}')
+
+        if [ -z "$EXPECTED" ]; then
+          echo "Error: no checksum found for ${BINARY}" >&2
+          exit 1
+        fi
+        if [ "$EXPECTED" != "$ACTUAL" ]; then
+          echo "Error: checksum mismatch!" >&2
+          echo "  Expected: $EXPECTED" >&2
+          echo "  Actual:   $ACTUAL" >&2
+          exit 1
+        fi
+
+        chmod +x "${{ runner.temp }}/review-bot"
+        echo "Installed review-bot ${VERSION} (checksum verified)"
+
+    - name: Run review
+      shell: bash
+      env:
+        GITHUB_SERVER_URL: ${{ inputs.gitea-url || github.server_url }}
+        GITHUB_REPOSITORY: ${{ inputs.repo || github.repository }}
+        PR_NUMBER: ${{ inputs.pr-number || github.event.pull_request.number }}
+        REVIEWER_TOKEN: ${{ inputs.reviewer-token }}
+        REVIEWER_NAME: ${{ inputs.reviewer-name }}
+        LLM_BASE_URL: ${{ inputs.llm-base-url }}
+        LLM_API_KEY: ${{ inputs.llm-api-key }}
+        LLM_MODEL: ${{ inputs.llm-model }}
+        CONVENTIONS_FILE: ${{ inputs.conventions-file }}
+        PATTERNS_REPO: ${{ inputs.patterns-repo }}
+        PATTERNS_FILES: ${{ inputs.patterns-files }}
+        LLM_TEMPERATURE: ${{ inputs.temperature }}
+        LLM_TIMEOUT: ${{ inputs.timeout }}
+        LLM_PROVIDER: ${{ inputs.llm-provider }}
+        UPDATE_EXISTING: ${{ inputs.update-existing }}
+        SYSTEM_PROMPT_FILE: ${{ inputs.system-prompt-file }}
+        PERSONA: ${{ inputs.persona }}
+        PERSONA_FILE: ${{ inputs.persona-file }}
+        AICORE_CLIENT_ID: ${{ inputs.aicore-client-id }}
+        AICORE_CLIENT_SECRET: ${{ inputs.aicore-client-secret }}
+        AICORE_AUTH_URL: ${{ inputs.aicore-auth-url }}
+        AICORE_API_URL: ${{ inputs.aicore-api-url }}
+        AICORE_RESOURCE_GROUP: ${{ inputs.aicore-resource-group }}
+      run: |
+        ARGS=""
+        if [ "${{ inputs.dry-run }}" = "true" ]; then
+          ARGS="--dry-run"
+        fi
+        ${{ runner.temp }}/review-bot $ARGS

.github/workflows/ci.yml

@@ -0,0 +1,69 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    types: [opened, synchronize]
+
+jobs:
+  test:
+    runs-on: ubuntu-24.04
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-go@v5
+        with:
+          go-version: '1.26'
+      - run: go test ./...
+      - run: go vet ./...
+      - run: go build -o review-bot ./cmd/review-bot
+
+  # Self-review using native SAP AI Core provider
+  # Models must match SAP AI Core deployments
+  # Available models: gpt-5, anthropic--claude-4.6-sonnet, anthropic--claude-4.6-opus
+  # Removed gpt-4.1, gpt-5-mini, gpt-4.1-mini - not deployed on AI Core
+  review:
+    runs-on: ubuntu-24.04
+    if: github.event_name == 'pull_request'
+    needs: test
+    strategy:
+      matrix:
+        include:
+          - name: sonnet
+            token_secret: SONNET_REVIEW_TOKEN
+            model: anthropic--claude-4.6-sonnet
+          - name: gpt
+            token_secret: GPT_REVIEW_TOKEN
+            model: gpt-5
+          - name: security
+            token_secret: SECURITY_REVIEW_TOKEN
+            model: gpt-5
+            patterns_repo: rodin/security-patterns
+            patterns_files: "."
+            system_prompt_file: SECURITY_REVIEW.md
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-go@v5
+        with:
+          go-version: '1.26'
+      - run: go build -o review-bot ./cmd/review-bot
+      - name: Run ${{ matrix.name }} review
+        env:
+          GITHUB_SERVER_URL: ${{ github.server_url }}
+          GITHUB_REPOSITORY: ${{ github.repository }}
+          PR_NUMBER: ${{ github.event.pull_request.number }}
+          REVIEWER_TOKEN: ${{ secrets[matrix.token_secret] }}
+          REVIEWER_NAME: ${{ matrix.name }}
+          LLM_PROVIDER: aicore
+          LLM_MODEL: ${{ matrix.model }}
+          AICORE_CLIENT_ID: ${{ secrets.AICORE_CLIENT_ID }}
+          AICORE_CLIENT_SECRET: ${{ secrets.AICORE_CLIENT_SECRET }}
+          AICORE_AUTH_URL: ${{ secrets.AICORE_AUTH_URL }}
+          AICORE_API_URL: ${{ secrets.AICORE_API_URL }}
+          AICORE_RESOURCE_GROUP: ${{ secrets.AICORE_RESOURCE_GROUP }}
+          CONVENTIONS_FILE: "CONVENTIONS.md"
+          PATTERNS_REPO: ${{ matrix.patterns_repo || 'rodin/go-patterns' }}
+          PATTERNS_FILES: ${{ matrix.patterns_files || 'README.md,patterns/' }}
+          LLM_TIMEOUT: "600"
+          SYSTEM_PROMPT_FILE: ${{ matrix.system_prompt_file }}
+        run: ./review-bot

.github/workflows/pr-ready-gate.yml

@@ -0,0 +1,38 @@
+name: PR Ready Gate
+
+on:
+  pull_request:
+    types: [synchronize]
+
+jobs:
+  clear-labels:
+    runs-on: ubuntu-24.04
+    # Always run - curl commands are safe if labels don't exist
+    steps:
+      - name: Remove ready and self-reviewed labels, reassign to author
+        env:
+          GITEA_TOKEN: ${{ secrets.RODIN_TOKEN }}
+        run: |
+          PR_NUMBER=${{ github.event.pull_request.number }}
+          AUTHOR=${{ github.event.pull_request.user.login }}
+          READY_LABEL_ID=38
+          SELF_REVIEWED_LABEL_ID=37
+          
+          # Remove ready label if present
+          curl -sS -X DELETE \
+            -H "Authorization: token $GITEA_TOKEN" \
+            "https://gitea.weiker.me/api/v1/repos/${{ github.repository }}/issues/${PR_NUMBER}/labels/${READY_LABEL_ID}" || true
+          
+          # Remove self-reviewed label if present
+          curl -sS -X DELETE \
+            -H "Authorization: token $GITEA_TOKEN" \
+            "https://gitea.weiker.me/api/v1/repos/${{ github.repository }}/issues/${PR_NUMBER}/labels/${SELF_REVIEWED_LABEL_ID}" || true
+          
+          # Reassign to author
+          curl -sS -X PATCH \
+            -H "Authorization: token $GITEA_TOKEN" \
+            -H "Content-Type: application/json" \
+            -d "{\"assignees\": [\"${AUTHOR}\"]}" \
+            "https://gitea.weiker.me/api/v1/repos/${{ github.repository }}/pulls/${PR_NUMBER}"
+          
+          echo "Cleared ready/self-reviewed labels and reassigned PR #${PR_NUMBER} to ${AUTHOR}"

.github/workflows/release.yml

@@ -0,0 +1,97 @@
+name: Release
+
+on:
+  push:
+    tags:
+      - 'v*'
+
+jobs:
+  release:
+    runs-on: ubuntu-24.04
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-go@v5
+        with:
+          go-version: '1.26'
+
+      - name: Run tests
+        run: |
+          go vet ./...
+          go test ./...
+
+      - name: Build binaries
+        run: |
+          VERSION=${GITHUB_REF_NAME}
+          mkdir -p dist
+
+          GOOS=linux GOARCH=amd64 go build -ldflags "-s -w -X main.version=${VERSION}" -o dist/review-bot-linux-amd64 ./cmd/review-bot
+          GOOS=linux GOARCH=arm64 go build -ldflags "-s -w -X main.version=${VERSION}" -o dist/review-bot-linux-arm64 ./cmd/review-bot
+          GOOS=darwin GOARCH=amd64 go build -ldflags "-s -w -X main.version=${VERSION}" -o dist/review-bot-darwin-amd64 ./cmd/review-bot
+          GOOS=darwin GOARCH=arm64 go build -ldflags "-s -w -X main.version=${VERSION}" -o dist/review-bot-darwin-arm64 ./cmd/review-bot
+
+          cd dist && sha256sum * > checksums.txt
+
+      - name: Create release and upload assets
+        env:
+          GITEA_TOKEN: ${{ secrets.RELEASE_TOKEN }}
+        run: |
+          VERSION=${GITHUB_REF_NAME}
+          GITEA_URL="${{ github.server_url }}"
+          REPO="${{ github.repository }}"
+
+          # Create release (or find existing one for this tag)
+          HTTP_CODE=$(curl -s -o /tmp/release_response.json -w "%{http_code}" -X POST \
+            -H "Authorization: token ${GITEA_TOKEN}" \
+            -H "Content-Type: application/json" \
+            "${GITEA_URL}/api/v1/repos/${REPO}/releases" \
+            -d "{\"tag_name\": \"${VERSION}\", \"name\": \"${VERSION}\", \"body\": \"Release ${VERSION}\", \"draft\": false, \"prerelease\": false}")
+
+          if [ "$HTTP_CODE" = "409" ]; then
+            echo "Release for ${VERSION} already exists, fetching existing..."
+            curl -sSf -o /tmp/release_response.json \
+              -H "Authorization: token ${GITEA_TOKEN}" \
+              "${GITEA_URL}/api/v1/repos/${REPO}/releases/tags/${VERSION}"
+          elif [ "$HTTP_CODE" != "201" ]; then
+            echo "Failed to create release (HTTP ${HTTP_CODE})" >&2
+            cat /tmp/release_response.json >&2
+            exit 1
+          fi
+
+          # Parse release ID (python3 available on ubuntu-24.04 runners)
+          RELEASE_ID=$(python3 -c "import json; print(json.load(open('/tmp/release_response.json'))['id'])")
+
+          if [ -z "$RELEASE_ID" ]; then
+            echo "Failed to parse release ID" >&2
+            cat /tmp/release_response.json >&2
+            exit 1
+          fi
+
+          echo "Release ID: ${RELEASE_ID}"
+
+          # Upload each asset (idempotent: delete existing asset with same name first)
+          for file in dist/*; do
+            filename=$(basename "$file")
+            echo "Uploading ${filename}..."
+
+            # Check if asset already exists and delete it
+            EXISTING_ID=$(export ASSET_NAME="${filename}"; curl -sS \
+              -H "Authorization: token ${GITEA_TOKEN}" \
+              "${GITEA_URL}/api/v1/repos/${REPO}/releases/${RELEASE_ID}/assets" \
+              | python3 -c "import json,sys,os; name=os.environ['ASSET_NAME']; assets=json.load(sys.stdin); print(next((str(a['id']) for a in assets if a['name']==name),''))" 2>/dev/null)
+
+            if [ -n "$EXISTING_ID" ]; then
+              echo "  Asset ${filename} already exists (id=${EXISTING_ID}), deleting..."
+              curl -sSf -X DELETE \
+                -H "Authorization: token ${GITEA_TOKEN}" \
+                "${GITEA_URL}/api/v1/repos/${REPO}/releases/${RELEASE_ID}/assets/${EXISTING_ID}"
+            fi
+
+            curl -sSf -X POST \
+              -H "Authorization: token ${GITEA_TOKEN}" \
+              -H "Content-Type: application/octet-stream" \
+              "${GITEA_URL}/api/v1/repos/${REPO}/releases/${RELEASE_ID}/assets?name=$(printf '%s' "${filename}" | jq -sRr @uri)" \
+              --data-binary "@${file}"
+          done
+
+          echo "Release ${VERSION} created with assets"

.gitignore

@@ -1 +1,2 @@
 /review-bot
+coverage.out

CONVENTIONS.md

@@ -2,8 +2,26 @@
 
 ## Language & Dependencies
 
-- Go standard library only — no external dependencies.
 - Target the latest stable Go release.
+- **STRICT ALLOWLIST:** Only packages listed below may be imported. No exceptions.
+
+### Approved Third-Party Packages
+
+| Package | Use Case | Scope |
+|---------|----------|-------|
+| `gopkg.in/yaml.v3` | YAML parsing (persona files, config) | production |
+| `github.com/google/go-cmp` | Test comparisons (`cmp.Diff`) | test only |
+
+**Any import not in this table or the Go standard library is forbidden.**
+
+Transitive dependencies of approved packages are automatically allowed.
+
+To request a new dependency:
+1. Open a PR that ONLY updates this table
+2. Requires explicit approval from Aaron
+3. After merge, a separate PR may use the package
+
+*Enforcement: `scripts/check-deps.sh` parses this table — update only here.*
 
 ## Error Handling
 

Makefile

@@ -0,0 +1,26 @@
+.PHONY: build test test-integration lint clean coverage check-deps precommit
+
+build:
+	go build -o review-bot ./cmd/review-bot/
+
+test:
+	go test ./...
+
+test-integration:
+	go test -tags integration -v ./cmd/review-bot/
+
+lint:
+	go vet ./...
+
+check-deps:
+	@./scripts/check-deps.sh
+
+clean:
+	rm -f review-bot
+
+coverage:
+	go test -coverprofile=coverage.out ./...
+	go tool cover -func=coverage.out
+
+# Precommit runs all checks required before pushing
+precommit: check-deps lint test

README.md

@@ -1,17 +1,284 @@
 # review-bot
 
-Automated code review bot for Gitea. Fetches a pull request diff, sends it to an LLM for analysis, and posts a structured review back to the PR.
+AI-powered code review bot for Gitea pull requests. Fetches diff + context, sends to an LLM, and posts a structured review (APPROVE / REQUEST_CHANGES) back to the PR.
 
 ## Features
 
-- Fetches PR metadata, diff, and CI status from Gitea API
-- Sends context-rich prompts to any OpenAI-compatible LLM
-- Parses structured JSON review responses
-- Posts formatted reviews (APPROVE / REQUEST_CHANGES) back to Gitea
-- Supports custom coding conventions via repo files
-- Zero external dependencies — Go stdlib only
+- **Multi-provider**: OpenAI-compatible, Anthropic Messages API, and SAP AI Core
+- **Context-aware**: Fetches full file content, conventions, language patterns, CI status
+- **Smart budget**: Automatically trims context to fit model token limits
+- **Idempotent reviews**: Posts new review, then cleans up stale ones (one review per bot)
+- **Custom prompts**: Load additional instructions from a file (e.g. security-focused review)
+- **Minimal dependencies**: Go stdlib + `gopkg.in/yaml.v3` only
 
-## Usage
+## Quick Start: Composite Action
+
+The easiest way to use review-bot in your Gitea CI:
+
+```yaml
+# .gitea/workflows/review.yml
+name: Review
+on:
+  pull_request:
+    types: [opened, synchronize]
+
+jobs:
+  review:
+    runs-on: ubuntu-24.04
+    steps:
+      - uses: actions/checkout@v4
+      - uses: https://gitea.weiker.me/rodin/review-bot/.gitea/actions/review@v0.1.0
+        with:
+          reviewer-token: ${{ secrets.REVIEW_TOKEN }}
+          reviewer-name: code-review
+          llm-base-url: ${{ secrets.LLM_BASE_URL }}
+          llm-api-key: ${{ secrets.LLM_API_KEY }}
+          llm-model: gpt-4.1
+```
+
+That's it. Every PR gets an automated review.
+
+## Examples
+
+### Single reviewer with conventions
+
+```yaml
+jobs:
+  review:
+    runs-on: ubuntu-24.04
+    steps:
+      - uses: actions/checkout@v4
+      - uses: https://gitea.weiker.me/rodin/review-bot/.gitea/actions/review@v0.1.0
+        with:
+          reviewer-token: ${{ secrets.REVIEW_TOKEN }}
+          reviewer-name: reviewer
+          llm-base-url: ${{ secrets.LLM_BASE_URL }}
+          llm-api-key: ${{ secrets.LLM_API_KEY }}
+          llm-model: gpt-4.1
+          conventions-file: CONVENTIONS.md
+          timeout: '600'
+```
+
+### Two reviewers with different models (diversity of opinion)
+
+```yaml
+jobs:
+  review:
+    runs-on: ubuntu-24.04
+    strategy:
+      matrix:
+        include:
+          - name: gpt
+            model: gpt-4.1
+            token_secret: GPT_REVIEW_TOKEN
+          - name: claude
+            model: claude-sonnet-4-20250514
+            token_secret: CLAUDE_REVIEW_TOKEN
+            provider: anthropic
+    steps:
+      - uses: actions/checkout@v4
+      - uses: https://gitea.weiker.me/rodin/review-bot/.gitea/actions/review@v0.1.0
+        with:
+          reviewer-token: ${{ secrets[matrix.token_secret] }}
+          reviewer-name: ${{ matrix.name }}
+          llm-base-url: ${{ secrets.LLM_BASE_URL }}
+          llm-api-key: ${{ secrets.LLM_API_KEY }}
+          llm-model: ${{ matrix.model }}
+          llm-provider: ${{ matrix.provider }}
+          conventions-file: CONVENTIONS.md
+```
+
+Each reviewer posts independently and only cleans up its own stale reviews.
+
+### Multiple review types from a single bot account
+
+Use the same Gitea token but different `reviewer-name` values to run specialized reviews without needing multiple bot accounts:
+
+```yaml
+jobs:
+  review:
+    runs-on: ubuntu-24.04
+    strategy:
+      matrix:
+        include:
+          - name: code-quality
+            model: gpt-4.1
+          - name: security
+            model: gpt-4.1
+            system_prompt_file: .review/SECURITY.md
+          - name: performance
+            model: gpt-4.1
+            system_prompt_file: .review/PERFORMANCE.md
+    steps:
+      - uses: actions/checkout@v4
+      - uses: https://gitea.weiker.me/rodin/review-bot/.gitea/actions/review@v0.1.0
+        with:
+          reviewer-token: ${{ secrets.REVIEW_TOKEN }}
+          reviewer-name: ${{ matrix.name }}
+          llm-base-url: ${{ secrets.LLM_BASE_URL }}
+          llm-api-key: ${{ secrets.LLM_API_KEY }}
+          llm-model: ${{ matrix.model }}
+          system-prompt-file: ${{ matrix.system_prompt_file }}
+```
+
+The sentinel `<!-- review-bot:security -->` ensures the security review only replaces previous security reviews, never the code-quality or performance reviews.
+
+### With language patterns from another repo
+
+```yaml
+- uses: https://gitea.weiker.me/rodin/review-bot/.gitea/actions/review@v0.1.0
+  with:
+    reviewer-token: ${{ secrets.REVIEW_TOKEN }}
+    reviewer-name: reviewer
+    llm-base-url: ${{ secrets.LLM_BASE_URL }}
+    llm-api-key: ${{ secrets.LLM_API_KEY }}
+    llm-model: gpt-4.1
+    conventions-file: CLAUDE.md
+    patterns-repo: rodin/go-patterns,rodin/kubernetes-conventions
+    patterns-files: "README.md,patterns/"
+```
+
+Pattern repos are fetched at review time. The reviewer uses them as criteria for idiomatic code.
+
+### Dry run (test without posting)
+
+```yaml
+- uses: https://gitea.weiker.me/rodin/review-bot/.gitea/actions/review@v0.1.0
+  with:
+    reviewer-token: ${{ secrets.REVIEW_TOKEN }}
+    reviewer-name: test
+    llm-base-url: ${{ secrets.LLM_BASE_URL }}
+    llm-api-key: ${{ secrets.LLM_API_KEY }}
+    llm-model: gpt-4.1
+    dry-run: 'true'
+```
+
+Prints the review to CI logs without posting to the PR. Useful for testing prompt changes.
+
+### Using Anthropic directly
+
+```yaml
+- uses: https://gitea.weiker.me/rodin/review-bot/.gitea/actions/review@v0.1.0
+  with:
+    reviewer-token: ${{ secrets.REVIEW_TOKEN }}
+    reviewer-name: claude
+    llm-base-url: https://api.anthropic.com
+    llm-api-key: ${{ secrets.ANTHROPIC_API_KEY }}
+    llm-model: claude-sonnet-4-20250514
+    llm-provider: anthropic
+```
+
+### Using SAP AI Core
+
+For SAP environments with AI Core deployments, use the `aicore` provider for native authentication:
+
+```yaml
+- uses: https://gitea.weiker.me/rodin/review-bot/.gitea/actions/review@v0.1.0
+  with:
+    reviewer-token: ${{ secrets.REVIEW_TOKEN }}
+    reviewer-name: aicore-review
+    llm-model: anthropic--claude-4.6-sonnet  # or gpt-5
+    llm-provider: aicore
+    aicore-client-id: ${{ secrets.AICORE_CLIENT_ID }}
+    aicore-client-secret: ${{ secrets.AICORE_CLIENT_SECRET }}
+    aicore-auth-url: ${{ secrets.AICORE_AUTH_URL }}
+    aicore-api-url: ${{ secrets.AICORE_API_URL }}
+    aicore-resource-group: default
+```
+
+AI Core handles OAuth token management and deployment discovery automatically. Model names must match the deployment name in AI Core (e.g. `anthropic--claude-4.6-sonnet`, `gpt-5`).
+
+## Action Inputs
+
+| Input | Required | Default | Description |
+|-------|----------|---------|-------------|
+| `reviewer-token` | Yes | — | Gitea token for posting reviews (needs `write:issue`, `write:repository`) |
+| `reviewer-name` | No | `""` | Logical identity for this reviewer. Used as sentinel for idempotent cleanup. Set this when running multiple review bots on the same PR. |
+| `llm-base-url` | No* | `""` | LLM API base URL (required unless using aicore provider) |
+| `llm-api-key` | No* | `""` | LLM API key (required unless using aicore provider) |
+| `llm-model` | Yes | — | Model name |
+| `llm-provider` | No | `openai` | API provider: `openai`, `anthropic`, or `aicore` |
+| `aicore-client-id` | No** | `""` | SAP AI Core client ID |
+| `aicore-client-secret` | No** | `""` | SAP AI Core client secret |
+| `aicore-auth-url` | No** | `""` | SAP AI Core authentication URL |
+| `aicore-api-url` | No** | `""` | SAP AI Core API URL |
+| `aicore-resource-group` | No | `default` | SAP AI Core resource group |
+| `conventions-file` | No | `""` | Path to coding conventions file in the repo |
+| `patterns-repo` | No | `""` | Comma-separated repos with language patterns (e.g. `rodin/go-patterns`) |
+| `patterns-files` | No | `README.md` | Files/directories to fetch from pattern repos |
+| `system-prompt-file` | No | `""` | Local file with additional system prompt instructions |
+| `persona` | No | `""` | Built-in persona name (security, architect, docs) |
+| `persona-file` | No | `""` | Path to persona file (YAML or JSON) with custom review focus |
+| `temperature` | No | `0` | LLM temperature (0 = server default) |
+| `timeout` | No | `300` | LLM request timeout in seconds |
+| `dry-run` | No | `false` | Print review to stdout instead of posting |
+| `update-existing` | No | `true` | Delete previous review from same bot before posting. Accepts: true/1/yes or false/0/no |
+| `version` | No | `latest` | review-bot version to install |
+
+*Required for `openai` and `anthropic` providers, not for `aicore`.
+**Required only for `aicore` provider.
+
+## Runner Requirements
+
+The composite action requires these tools on the runner:
+
+| Tool | Used For |
+|------|----------|
+| `python3` | JSON parsing during version detection |
+| `sha256sum` | Checksum verification of downloaded binary |
+| `curl` | Downloading releases and querying the API |
+
+All three are pre-installed on `ubuntu-*` runners (e.g. `ubuntu-24.04`). If you use a custom runner image, ensure these are available.
+
+## How Review Cleanup Works
+
+When `reviewer-name` is set, the bot embeds a hidden sentinel in each review:
+
+```html
+<!-- review-bot:code-review -->
+```
+
+On the next run, it finds and deletes any review containing its own sentinel (except the one it just posted). This means:
+
+- **One review per bot per PR** — no clutter from repeated pushes
+- **Multiple bots coexist** — each only cleans up its own reviews
+- **Same token, different roles** — a single bot account can post "code-review" and "security" reviews without conflict
+- **No extra permissions** — identity comes from the sentinel, not the API
+
+If `reviewer-name` is empty, cleanup is skipped (reviews stack like before).
+
+### Shared Token: Worst-Wins Behavior
+
+When multiple review types share the same Gitea bot account (e.g. code-quality and security), Gitea determines the user's approval state from their **most recent review**. This creates a race condition: if security finds issues (REQUEST_CHANGES) but code-quality finishes last (APPROVE), the PR appears approved.
+
+review-bot handles this automatically with **worst-wins reconciliation**: before posting, each job checks whether any sibling review from the same user already has REQUEST_CHANGES. If so and this job would post APPROVE, it posts as REQUEST_CHANGES instead — maintaining the block. This ensures the PR stays blocked until all checks pass, regardless of execution order.
+
+**If you need independent approval/block per review type**, use separate Gitea bot accounts with their own tokens.
+
+## Custom Review Prompts
+
+Use `system-prompt-file` to specialize the review focus. The file contents are appended to the base system prompt as "Additional Review Instructions."
+
+Example `SECURITY_REVIEW.md`:
+
+```markdown
+You are performing a security-focused code review.
+
+Focus areas:
+- Injection attacks (SQL, command, path traversal, template)
+- Authentication/Authorization (missing checks, privilege escalation)
+- Secrets exposure (hardcoded credentials, tokens in logs)
+- Input validation (unsanitized input, unsafe deserialization)
+- Race conditions (TOCTOU, unsynchronized shared state)
+
+Rules:
+- Only report findings with security implications
+- Ignore style, naming, and general code quality
+- MAJOR = exploitable vulnerability, MINOR = hardening opportunity, NIT = theoretical risk
+- If no security-relevant changes exist, APPROVE with empty findings
+```
+
+## CLI Usage
 
 ```bash
 review-bot \
@@ -19,73 +286,190 @@ review-bot \
   --repo owner/name \
   --pr 42 \
   --reviewer-token "$GITEA_TOKEN" \
+  --reviewer-name "code-review" \
   --llm-base-url https://api.openai.com/v1 \
   --llm-api-key "$OPENAI_API_KEY" \
-  --llm-model gpt-4 \
-  --reviewer-name "Sonnet" \
-  --conventions-file CONVENTIONS.md \
-  --dry-run
+  --llm-model gpt-4.1 \
+  --conventions-file CONVENTIONS.md
 ```
 
 ## Environment Variables
 
-All flags can be set via environment variables:
+All flags have environment variable equivalents:
 
-| Flag | Env Var | Required | Description |
-|------|---------|----------|-------------|
-| `--gitea-url` | `GITEA_URL` | Yes | Gitea instance base URL |
-| `--repo` | `GITEA_REPO` | Yes | Repository in `owner/name` format |
-| `--pr` | `PR_NUMBER` | Yes | Pull request number |
-| `--reviewer-token` | `REVIEWER_TOKEN` | Yes | Gitea API token for posting reviews |
-| `--llm-base-url` | `LLM_BASE_URL` | Yes | OpenAI-compatible API base URL |
-| `--llm-api-key` | `LLM_API_KEY` | Yes | LLM API key |
-| `--llm-model` | `LLM_MODEL` | Yes | Model identifier |
-| `--reviewer-name` | `REVIEWER_NAME` | No | Display name in review footer |
-| `--conventions-file` | `CONVENTIONS_FILE` | No | Path to conventions file in repo |
-| `--dry-run` | — | No | Print review to stdout instead of posting |
+| Flag | Env Var |
+|------|---------|
+| `--gitea-url` | `GITEA_URL` |
+| `--repo` | `GITEA_REPO` |
+| `--pr` | `PR_NUMBER` |
+| `--reviewer-token` | `REVIEWER_TOKEN` |
+| `--reviewer-name` | `REVIEWER_NAME` |
+| `--llm-base-url` | `LLM_BASE_URL` |
+| `--llm-api-key` | `LLM_API_KEY` |
+| `--llm-model` | `LLM_MODEL` |
+| `--llm-provider` | `LLM_PROVIDER` |
+| `--conventions-file` | `CONVENTIONS_FILE` |
+| `--patterns-repo` | `PATTERNS_REPO` |
+| `--patterns-files` | `PATTERNS_FILES` |
+| `--system-prompt-file` | `SYSTEM_PROMPT_FILE` |
+| `--llm-temperature` | `LLM_TEMPERATURE` |
+| `--llm-timeout` | `LLM_TIMEOUT` |
+| `--update-existing` | `UPDATE_EXISTING` |
 
-## Adding to a Gitea Repository
+## Setup
 
-1. Build the binary or use the CI workflow approach (build in CI).
+1. **Create a Gitea bot account** (e.g. `review-bot`)
+2. **Generate a token** with scopes: `write:issue`, `write:repository`
+3. **Add secrets** to your Gitea repo (Settings → Actions → Secrets):
+   - `REVIEW_TOKEN` — the bot's Gitea token
+   - `LLM_BASE_URL` — your LLM endpoint
+   - `LLM_API_KEY` — your LLM key
+4. **Add the workflow** (see Quick Start above)
 
-2. Add secrets to your Gitea repo (Settings → Actions → Secrets):
-   - `SONNET_REVIEW_TOKEN` — Gitea token for the Sonnet reviewer account
-   - `GPT_REVIEW_TOKEN` — Gitea token for the GPT reviewer account
-   - `LLM_BASE_URL` — Your LLM API endpoint
-   - `LLM_API_KEY` — Your LLM API key
+### Token Scopes Required
 
-3. Copy `.gitea/workflows/ci.yml` to your repo (or adapt it).
+| Scope | Purpose |
+|-------|--------|
+| `write:issue` | Post and delete reviews |
+| `write:repository` | Read PR diffs, file content, commit statuses |
+| `read:user` | Self-request as reviewer (optional but recommended) |
 
-4. On every PR, the bot will:
-   - Run tests and vet
-   - Build review-bot
-   - Post reviews from each configured LLM reviewer
+Without `read:user`, the bot still works but cannot add itself to the PR's reviewer list.
 
 ## Development
 
 ```bash
-# Run tests
-go test ./...
-
-# Run vet
-go vet ./...
-
-# Build
+go test ./...        # Unit tests
+go vet ./...         # Static analysis
 go build -o review-bot ./cmd/review-bot
 
-# Integration tests (requires env vars)
+# Integration tests (requires env vars set)
 go test -tags=integration ./...
 ```
 
 ## Architecture
 
 ```
-cmd/review-bot/     CLI entrypoint
-gitea/              Gitea API client
-llm/                OpenAI-compatible LLM client
+cmd/review-bot/     CLI entrypoint + orchestration
+gitea/              Gitea API client (reviews, PRs, files)
+llm/                Multi-provider LLM client (OpenAI + Anthropic)
 review/             Prompt building, response parsing, formatting
+budget/             Token estimation + context trimming
 ```
 
 ## License
 
 MIT
+
+## Review Personas
+
+Personas provide role-based review specialization. Instead of generic code review, each persona focuses on a specific domain (security, architecture, documentation) with tailored prompts and severity calibration.
+
+### Built-in Personas
+
+| Persona | Focus |
+|---------|-------|
+| `security` | Vulnerabilities, auth bypass, secrets exposure, injection attacks |
+| `architect` | Design patterns, code organization, API contracts, testability |
+| `docs` | Documentation quality, API clarity, error messages |
+
+### Using Built-in Personas
+
+```yaml
+- uses: rodin/review-bot/.gitea/actions/review@v1
+  with:
+    reviewer-name: security
+    persona: security
+    llm-model: claude-opus-4-20250514  # Security benefits from strong reasoning
+    ...
+```
+
+### Multiple Personas in Parallel
+
+```yaml
+jobs:
+  review:
+    strategy:
+      matrix:
+        include:
+          - name: security
+            persona: security
+          - name: architect
+            persona: architect
+    steps:
+      - uses: rodin/review-bot/.gitea/actions/review@v1
+        with:
+          reviewer-name: ${{ matrix.name }}
+          persona: ${{ matrix.persona }}
+          ...
+```
+
+Each persona posts independently with its own sentinel, so reviews don't interfere.
+
+
+### Custom Personas
+
+Create a YAML file with your domain-specific review focus:
+
+```yaml
+# .review/personas/trading.yaml
+name: trading
+display_name: Trading Domain Expert
+
+identity: |
+  You are a trading systems expert reviewing code for correctness.
+
+  Your expertise:
+  - Order lifecycle and state machines
+  - Fill handling and partial fills
+  - Position tracking and P&L calculations
+  - Event sourcing invariants
+
+focus:
+  - Order state machine correctness
+  - Fill handling edge cases (partial, overfill)
+  - Position and P&L calculation accuracy
+  - Event replay determinism
+  - Decimal precision for money
+
+ignore:
+  - Code style
+  - General performance
+  - Documentation formatting
+
+severity:
+  major: "Bugs that cause incorrect positions, fills, or money calculations"
+  minor: "Edge cases that could cause issues under unusual conditions"
+  nit: "Clarity improvements for domain logic"
+```
+
+Use it in CI:
+
+```yaml
+- uses: rodin/review-bot/.gitea/actions/review@v1
+  with:
+    reviewer-name: trading
+    persona-file: .review/personas/trading.yaml
+    ...
+```
+
+YAML is the recommended format for personas because it supports:
+- Multi-line strings with `|` blocks (cleaner identity definitions)
+- Comments for documentation
+- More readable arrays and nested structures
+
+JSON is also supported for backwards compatibility—just use `.json` extension.
+
+
+### Persona vs system-prompt-file
+
+| Feature | `persona` / `persona-file` | `system-prompt-file` |
+|---------|---------------------------|----------------------|
+| Replaces base prompt | Yes | No (appends) |
+| Structured format | Yes (YAML/JSON) | No (freeform) |
+| Focus/ignore lists | Yes | Manual |
+| Severity calibration | Yes | Manual |
+| Header display name | Yes | No |
+| Built-in options | Yes | No |
+
+Use personas for domain-specialized reviews. Use `system-prompt-file` for minor tweaks to the generic review.

SECURITY_REVIEW.md

@@ -0,0 +1,18 @@
+You are performing a security-focused code review. Your primary concern is identifying vulnerabilities, not general code quality.
+
+Focus areas:
+- **Injection attacks**: SQL injection, command injection, path traversal, template injection
+- **Authentication/Authorization**: Missing auth checks, privilege escalation, IDOR
+- **Secrets exposure**: Hardcoded credentials, API keys in code, tokens in logs
+- **Input validation**: Untrusted input used without sanitization, unsafe deserialization
+- **Cryptography**: Weak algorithms, predictable randomness, improper key management
+- **Error handling**: Information leakage in error messages, stack traces exposed
+- **Dependencies**: Known vulnerable patterns, unsafe use of external libraries
+- **Race conditions**: TOCTOU bugs, unsynchronized shared state
+- **Resource exhaustion**: Unbounded allocations, missing timeouts, denial-of-service vectors
+
+Rules for this review:
+- Only report findings with actual security implications. Ignore style, naming, and general code quality.
+- Severity mapping: MAJOR = exploitable vulnerability or data exposure. MINOR = defense-in-depth improvement or hardening opportunity. NIT = theoretical concern with low practical risk.
+- If the code has no security-relevant changes, APPROVE with an empty findings list.
+- Do not duplicate findings that a standard code review would catch (logic bugs, missing error checks) unless they have a security dimension.

budget/budget.go

@@ -0,0 +1,226 @@
+// Package budget manages LLM context window budgeting for review-bot.
+//
+// It estimates token usage and progressively trims context content to fit
+// within model-specific limits. The trimming order (least important first):
+// patterns → conventions → file context → diff truncation.
+package budget
+
+import (
+	"fmt"
+	"strings"
+	"unicode/utf8"
+)
+
+// modelLimit pairs a model name prefix with its context window size.
+type modelLimit struct {
+	prefix string
+	limit  int
+}
+
+// Known model context limits (in tokens), ordered longest-prefix-first
+// for deterministic matching.
+var modelLimits = []modelLimit{
+	{"claude-haiku-3.5-20241022", 200_000},
+	{"claude-sonnet-4-20250514", 200_000},
+	{"claude-opus-4-20250514", 200_000},
+	{"gpt-4.1-mini", 128_000},
+	{"gpt-5-mini", 200_000},
+	{"gpt-4.1", 128_000},
+	{"gpt-5", 200_000},
+}
+
+const defaultLimit = 128_000
+
+// reserveTokens is headroom for the response generation.
+const reserveTokens = 4_000
+
+const diffTruncMarker = "\n\n... [diff truncated due to context limit] ..."
+const diffTooLargeMarker = "... [diff too large for context window — review manually] ..."
+const userMetaTruncMarker = "\n... [description truncated] ..."
+
+// EstimateTokens estimates the number of tokens in a string.
+// Uses the rough heuristic of ~4 bytes per token, which is
+// conservative for English text and code.
+func EstimateTokens(s string) int {
+	return len(s) / 4
+}
+
+// LimitForModel returns the context window size for the given model.
+// Uses longest-prefix-first matching for deterministic results.
+func LimitForModel(model string) int {
+	for _, ml := range modelLimits {
+		if model == ml.prefix || strings.HasPrefix(model, ml.prefix) {
+			return ml.limit
+		}
+	}
+	return defaultLimit
+}
+
+// Sections holds the prompt content sections in trim priority order.
+// When the total exceeds the budget, sections are trimmed from least
+// important (Patterns) to most important (Diff).
+type Sections struct {
+	SystemBase  string // Core instructions (never trimmed)
+	Patterns    string // Language patterns (trimmed first)
+	Conventions string // Repo conventions (trimmed second)
+	FileContext string // Full file content (trimmed third)
+	Diff        string // The actual diff (trimmed last, only truncated)
+	UserMeta    string // PR title, description, CI status (truncated only if base exceeds budget)
+}
+
+// Result holds the trimmed content and metadata about what was dropped.
+type Result struct {
+	SystemPrompt string
+	UserPrompt   string
+	Trimmed      []string // Human-readable descriptions of what was trimmed
+	EstTokens    int      // Estimated total tokens after trimming
+}
+
+// Fit trims sections to fit within the model's context limit.
+// Returns the assembled prompts and a list of what was trimmed.
+func Fit(model string, sections Sections) Result {
+	limit := LimitForModel(model) - reserveTokens
+
+	baseTokens := EstimateTokens(sections.SystemBase) + EstimateTokens(sections.UserMeta)
+	available := limit - baseTokens
+	if available < 0 {
+		// Base content alone exceeds budget. Truncate UserMeta (keep first ~1000 tokens).
+		if len(sections.UserMeta) > 4000 {
+			sections.UserMeta = truncateUTF8(sections.UserMeta, 4000) + userMetaTruncMarker
+			baseTokens = EstimateTokens(sections.SystemBase) + EstimateTokens(sections.UserMeta)
+			available = limit - baseTokens
+		}
+		if available < 0 {
+			available = 0
+		}
+	}
+
+	// Trimmable sections in priority order (first = dropped first)
+	type entry struct {
+		name    string
+		content *string
+	}
+	entries := []entry{
+		{"patterns", &sections.Patterns},
+		{"conventions", &sections.Conventions},
+		{"file context", &sections.FileContext},
+	}
+
+	// Check if everything fits
+	totalTrimmable := EstimateTokens(sections.Diff)
+	for _, e := range entries {
+		totalTrimmable += EstimateTokens(*e.content)
+	}
+
+	var trimmed []string
+	if totalTrimmable > available {
+		// Trim from least important
+		for i := range entries {
+			tokens := EstimateTokens(*entries[i].content)
+			if tokens == 0 {
+				continue
+			}
+			trimmed = append(trimmed, fmt.Sprintf("%s (~%dK tokens)", entries[i].name, tokens/1000))
+			*entries[i].content = ""
+
+			// Recalculate
+			totalTrimmable = EstimateTokens(sections.Diff)
+			for _, e := range entries {
+				totalTrimmable += EstimateTokens(*e.content)
+			}
+			if totalTrimmable <= available {
+				break
+			}
+		}
+	}
+
+	// If still too large, truncate the diff
+	if totalTrimmable > available {
+		diffBudget := available
+		for _, e := range entries {
+			diffBudget -= EstimateTokens(*e.content)
+		}
+		if diffBudget < 0 {
+			diffBudget = 0
+		}
+		// Reserve space for truncation marker
+		markerBudget := EstimateTokens(diffTruncMarker)
+		effectiveBudget := diffBudget - markerBudget
+		if effectiveBudget < 0 {
+			effectiveBudget = 0
+		}
+		maxChars := effectiveBudget * 4
+		if maxChars < len(sections.Diff) {
+			removed := EstimateTokens(sections.Diff) - diffBudget
+			trimmed = append(trimmed, fmt.Sprintf("diff truncated (~%dK tokens removed)", removed/1000))
+			if maxChars > 0 {
+				if diffBudget >= markerBudget {
+					sections.Diff = truncateUTF8(sections.Diff, maxChars) + diffTruncMarker
+				} else {
+					sections.Diff = truncateUTF8(sections.Diff, maxChars)
+				}
+			} else {
+				sections.Diff = diffTooLargeMarker
+			}
+		}
+	}
+
+	finalTokens := baseTokens
+	for _, e := range entries {
+		finalTokens += EstimateTokens(*e.content)
+	}
+	finalTokens += EstimateTokens(sections.Diff)
+
+	return buildResult(sections, trimmed, finalTokens)
+}
+
+func buildResult(s Sections, trimmed []string, estTokens int) Result {
+	var sys strings.Builder
+	sys.WriteString(s.SystemBase)
+	if s.Patterns != "" {
+		sys.WriteString("\n\n## Language Patterns & Idioms\n\nUse the following patterns as review criteria. Code that violates these established patterns is a finding:\n\n")
+		sys.WriteString(s.Patterns)
+	}
+	if s.Conventions != "" {
+		sys.WriteString("\n\n## Repository Conventions\n\nThe repository has the following coding conventions that must be respected:\n\n")
+		sys.WriteString(s.Conventions)
+	}
+
+	var usr strings.Builder
+	usr.WriteString(s.UserMeta)
+	if s.FileContext != "" {
+		usr.WriteString("\n### Full File Context (modified files)\n\n")
+		usr.WriteString(s.FileContext)
+		usr.WriteString("\n")
+	}
+	if s.Diff != "" {
+		usr.WriteString("\n### Diff (changes to review)\n\n```diff\n")
+		usr.WriteString(s.Diff)
+		usr.WriteString("\n```\n")
+	}
+
+	if len(trimmed) > 0 {
+		usr.WriteString("\n⚠️ Note: Context was trimmed to fit model limits. Dropped: ")
+		usr.WriteString(strings.Join(trimmed, ", "))
+		usr.WriteString("\n")
+	}
+
+	return Result{
+		SystemPrompt: sys.String(),
+		UserPrompt:   usr.String(),
+		Trimmed:      trimmed,
+		EstTokens:    estTokens,
+	}
+}
+
+// truncateUTF8 truncates s to at most maxBytes without splitting multi-byte
+// UTF-8 characters. Returns a valid UTF-8 string of at most maxBytes bytes.
+func truncateUTF8(s string, maxBytes int) string {
+	if len(s) <= maxBytes {
+		return s
+	}
+	for maxBytes > 0 && !utf8.RuneStart(s[maxBytes]) {
+		maxBytes--
+	}
+	return s[:maxBytes]
+}

budget/budget_test.go

@@ -0,0 +1,203 @@
+package budget
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestEstimateTokens(t *testing.T) {
+	tests := []struct {
+		input string
+		want  int
+	}{
+		{"", 0},
+		{"abcd", 1},
+		{"12345678", 2},
+		{strings.Repeat("x", 400), 100},
+	}
+	for _, tt := range tests {
+		got := EstimateTokens(tt.input)
+		if got != tt.want {
+			t.Errorf("EstimateTokens(%d chars) = %d, want %d", len(tt.input), got, tt.want)
+		}
+	}
+}
+
+func TestLimitForModel(t *testing.T) {
+	tests := []struct {
+		model string
+		want  int
+	}{
+		{"gpt-4.1", 128_000},
+		{"gpt-5", 200_000},
+		{"gpt-5-mini", 200_000},
+		{"unknown-model", defaultLimit},
+		{"gpt-4.1-2026-01-01", 128_000}, // prefix match
+	}
+	for _, tt := range tests {
+		got := LimitForModel(tt.model)
+		if got != tt.want {
+			t.Errorf("LimitForModel(%q) = %d, want %d", tt.model, got, tt.want)
+		}
+	}
+}
+
+func TestFit_AllFits(t *testing.T) {
+	s := Sections{
+		SystemBase:  "system instructions",
+		Patterns:    "some patterns",
+		Conventions: "some conventions",
+		FileContext: "file content",
+		Diff:        "diff content",
+		UserMeta:    "PR: title\n",
+	}
+	result := Fit("gpt-5", s)
+
+	if len(result.Trimmed) != 0 {
+		t.Errorf("expected no trimming, got %v", result.Trimmed)
+	}
+	if !strings.Contains(result.SystemPrompt, "some patterns") {
+		t.Error("expected patterns in system prompt")
+	}
+	if !strings.Contains(result.SystemPrompt, "some conventions") {
+		t.Error("expected conventions in system prompt")
+	}
+	if !strings.Contains(result.UserPrompt, "file content") {
+		t.Error("expected file context in user prompt")
+	}
+}
+
+func TestFit_TrimsPatterns(t *testing.T) {
+	// Create content that exceeds 128K token budget for gpt-4.1
+	// Budget ≈ 128K - 4K reserve = 124K tokens = ~496K chars
+	// Fill patterns with enough to push over
+	bigPatterns := strings.Repeat("x", 500_000) // ~125K tokens
+	s := Sections{
+		SystemBase:  "base",
+		Patterns:    bigPatterns,
+		Conventions: "conventions",
+		FileContext: "files",
+		Diff:        "diff",
+		UserMeta:    "meta",
+	}
+	result := Fit("gpt-4.1", s)
+
+	if len(result.Trimmed) == 0 {
+		t.Fatal("expected trimming")
+	}
+	if !strings.Contains(result.Trimmed[0], "patterns") {
+		t.Errorf("expected patterns to be trimmed first, got %v", result.Trimmed)
+	}
+	if strings.Contains(result.SystemPrompt, bigPatterns[:100]) {
+		t.Error("expected patterns to be removed from output")
+	}
+	// Conventions should survive
+	if !strings.Contains(result.SystemPrompt, "conventions") {
+		t.Error("expected conventions to survive after patterns trimmed")
+	}
+}
+
+func TestFit_TrimsConventions(t *testing.T) {
+	// Patterns + conventions + diff all exceed budget even after patterns removed
+	big := strings.Repeat("y", 520_000) // ~130K tokens each (exceeds 124K budget even alone)
+	s := Sections{
+		SystemBase:  "base",
+		Patterns:    big,
+		Conventions: big,
+		FileContext: "files",
+		Diff:        "diff",
+		UserMeta:    "meta",
+	}
+	result := Fit("gpt-4.1", s)
+
+	if len(result.Trimmed) < 2 {
+		t.Fatalf("expected at least 2 trimmed, got %v", result.Trimmed)
+	}
+	if !strings.Contains(result.Trimmed[0], "patterns") {
+		t.Errorf("expected patterns trimmed first, got %s", result.Trimmed[0])
+	}
+	if !strings.Contains(result.Trimmed[1], "conventions") {
+		t.Errorf("expected conventions trimmed second, got %s", result.Trimmed[1])
+	}
+}
+
+func TestFit_TruncatesDiff(t *testing.T) {
+	// Only diff is huge, no patterns/conventions
+	hugeDiff := strings.Repeat("z", 600_000) // ~150K tokens > 128K limit
+	s := Sections{
+		SystemBase: "base",
+		Diff:       hugeDiff,
+		UserMeta:   "meta",
+	}
+	result := Fit("gpt-4.1", s)
+
+	if len(result.Trimmed) == 0 {
+		t.Fatal("expected diff truncation")
+	}
+	if !strings.Contains(result.Trimmed[len(result.Trimmed)-1], "diff truncated") {
+		t.Errorf("expected diff truncation note, got %v", result.Trimmed)
+	}
+	if !strings.Contains(result.UserPrompt, "[diff truncated due to context limit]") {
+		t.Error("expected truncation marker in user prompt")
+	}
+}
+
+func TestFit_PreservesNoteInOutput(t *testing.T) {
+	big := strings.Repeat("w", 500_000)
+	s := Sections{
+		SystemBase: "base",
+		Patterns:   big,
+		Diff:       "small diff",
+		UserMeta:   "meta",
+	}
+	result := Fit("gpt-4.1", s)
+
+	if !strings.Contains(result.UserPrompt, "⚠️ Note: Context was trimmed") {
+		t.Error("expected trimming note in user prompt")
+	}
+}
+
+
+func TestFit_HugeUserMeta(t *testing.T) {
+	// UserMeta so large that base alone exceeds limit
+	// Use a unique marker past the truncation point
+	hugeDesc := strings.Repeat("d", 5000) + "UNIQUE_MARKER_PAST_TRUNCATION" + strings.Repeat("d", 595_000)
+	s := Sections{
+		SystemBase: "base",
+		Diff:       "small diff",
+		UserMeta:   hugeDesc,
+	}
+	result := Fit("gpt-4.1", s)
+
+	limit := LimitForModel("gpt-4.1") - reserveTokens
+	if result.EstTokens > limit {
+		t.Errorf("EstTokens %d exceeds limit %d", result.EstTokens, limit)
+	}
+	// Content past truncation point should not be present
+	if strings.Contains(result.UserPrompt, "UNIQUE_MARKER_PAST_TRUNCATION") {
+		t.Error("expected UserMeta to be truncated but found content past truncation point")
+	}
+	// Truncation marker should be present
+	if !strings.Contains(result.UserPrompt, "[description truncated]") {
+		t.Error("expected truncation marker in output")
+	}
+}
+
+func TestFit_NeverExceedsLimit(t *testing.T) {
+	// All sections huge — verify final tokens never exceed limit
+	big := strings.Repeat("a", 200_000)
+	s := Sections{
+		SystemBase:  strings.Repeat("s", 8000),
+		Patterns:    big,
+		Conventions: big,
+		FileContext: big,
+		Diff:        big,
+		UserMeta:    strings.Repeat("m", 8000),
+	}
+	result := Fit("gpt-4.1", s)
+
+	limit := LimitForModel("gpt-4.1") - reserveTokens
+	if result.EstTokens > limit {
+		t.Errorf("EstTokens %d exceeds limit %d (trimmed: %v)", result.EstTokens, limit, result.Trimmed)
+	}
+}

cmd/review-bot/integration_test.go

@@ -0,0 +1,161 @@
+//go:build integration
+
+package main
+
+import (
+	"context"
+	"os"
+	"strconv"
+	"strings"
+	"testing"
+
+	"gitea.weiker.me/rodin/review-bot/gitea"
+	"gitea.weiker.me/rodin/review-bot/llm"
+	"gitea.weiker.me/rodin/review-bot/review"
+)
+
+// Integration test requires a running Gitea instance and LLM endpoint.
+// Set environment variables:
+//
+//	INTEGRATION_GITEA_URL     - Gitea base URL
+//	INTEGRATION_GITEA_TOKEN   - Gitea API token with repo access
+//	INTEGRATION_GITEA_REPO    - owner/repo with an open PR
+//	INTEGRATION_PR_NUMBER     - PR number to test against
+//	INTEGRATION_LLM_BASE_URL  - LLM API base URL
+//	INTEGRATION_LLM_API_KEY   - LLM API key
+//	INTEGRATION_LLM_MODEL     - Model name
+func TestIntegration_FullReviewFlow(t *testing.T) {
+	giteaURL := os.Getenv("INTEGRATION_GITEA_URL")
+	giteaToken := os.Getenv("INTEGRATION_GITEA_TOKEN")
+	giteaRepo := os.Getenv("INTEGRATION_GITEA_REPO")
+	prNumStr := os.Getenv("INTEGRATION_PR_NUMBER")
+	llmBaseURL := os.Getenv("INTEGRATION_LLM_BASE_URL")
+	llmAPIKey := os.Getenv("INTEGRATION_LLM_API_KEY")
+	llmModel := os.Getenv("INTEGRATION_LLM_MODEL")
+
+	if giteaURL == "" || giteaToken == "" || giteaRepo == "" || prNumStr == "" ||
+		llmBaseURL == "" || llmAPIKey == "" || llmModel == "" {
+		t.Skip("Integration test env vars not set, skipping")
+	}
+
+	prNumber, err := strconv.Atoi(prNumStr)
+	if err != nil {
+		t.Fatalf("Invalid PR number %q: %v", prNumStr, err)
+	}
+
+	// Parse owner/repo
+	parts := strings.SplitN(giteaRepo, "/", 2)
+	if len(parts) != 2 {
+		t.Fatalf("Invalid repo format %q", giteaRepo)
+	}
+	owner, repoName := parts[0], parts[1]
+	if owner == "" || repoName == "" {
+		t.Fatalf("Invalid repo format %q", giteaRepo)
+	}
+
+	ctx := context.Background()
+
+	// Step 1: Fetch PR
+	giteaClient := gitea.NewClient(giteaURL, giteaToken)
+	pr, err := giteaClient.GetPullRequest(ctx, owner, repoName, prNumber)
+	if err != nil {
+		t.Fatalf("GetPullRequest: %v", err)
+	}
+	t.Logf("PR: %s (sha: %s)", pr.Title, pr.Head.Sha)
+
+	// Step 2: Fetch diff
+	diff, err := giteaClient.GetPullRequestDiff(ctx, owner, repoName, prNumber)
+	if err != nil {
+		t.Fatalf("GetPullRequestDiff: %v", err)
+	}
+	if diff == "" {
+		t.Fatal("diff is empty")
+	}
+	t.Logf("Diff size: %d bytes", len(diff))
+
+	// Step 3: Build prompts
+	systemPrompt := review.BuildSystemPrompt("", "")
+	userPrompt := review.BuildUserPrompt(pr.Title, pr.Body, diff, "", true, "")
+
+	// Step 4: Call LLM
+	llmClient := llm.NewClient(llmBaseURL, llmAPIKey, llmModel)
+	response, err := llmClient.Complete(ctx, []llm.Message{
+		{Role: "system", Content: systemPrompt},
+		{Role: "user", Content: userPrompt},
+	})
+	if err != nil {
+		t.Fatalf("LLM Complete: %v", err)
+	}
+	t.Logf("LLM response: %d bytes", len(response))
+
+	// Step 5: Parse response
+	result, err := review.ParseResponse(response)
+	if err != nil {
+		t.Fatalf("ParseResponse: %v", err)
+	}
+	t.Logf("Verdict: %s, Findings: %d", result.Verdict, len(result.Findings))
+
+	// Step 6: Format (dry-run validation)
+	body := review.FormatMarkdown(result, "integration-test")
+	if body == "" {
+		t.Fatal("formatted review body is empty")
+	}
+	t.Logf("Review body:\n%s", body)
+}
+
+func TestIntegration_PostAndCleanup(t *testing.T) {
+	giteaURL := os.Getenv("INTEGRATION_GITEA_URL")
+	giteaToken := os.Getenv("INTEGRATION_GITEA_TOKEN")
+	giteaRepo := os.Getenv("INTEGRATION_GITEA_REPO")
+	prNumStr := os.Getenv("INTEGRATION_PR_NUMBER")
+
+	if giteaURL == "" || giteaToken == "" || giteaRepo == "" || prNumStr == "" {
+		t.Skip("Integration test env vars not set, skipping")
+	}
+
+	prNumber, err := strconv.Atoi(prNumStr)
+	if err != nil {
+		t.Fatalf("Invalid PR number %q: %v", prNumStr, err)
+	}
+
+	parts := strings.SplitN(giteaRepo, "/", 2)
+	if len(parts) != 2 {
+		t.Fatalf("Invalid repo format %q", giteaRepo)
+	}
+	owner, repoName := parts[0], parts[1]
+
+	ctx := context.Background()
+	giteaClient := gitea.NewClient(giteaURL, giteaToken)
+
+	// Post a test review
+	sentinel := "<!-- review-bot:integration-test -->"
+	testBody := "# Integration Test Review\n\nThis is a test review.\n\n" + sentinel
+	posted, err := giteaClient.PostReview(ctx, owner, repoName, prNumber, "COMMENT", testBody, nil)
+	if err != nil {
+		t.Fatalf("PostReview: %v", err)
+	}
+	t.Logf("Posted review ID: %d", posted.ID)
+
+	// Verify it appears in listing
+	reviews, err := giteaClient.ListReviews(ctx, owner, repoName, prNumber)
+	if err != nil {
+		t.Fatalf("ListReviews: %v", err)
+	}
+
+	found := false
+	for _, r := range reviews {
+		if r.ID == posted.ID && strings.Contains(r.Body, sentinel) {
+			found = true
+			break
+		}
+	}
+	if !found {
+		t.Error("posted review not found in listing")
+	}
+
+	// Cleanup: delete the test review
+	err = giteaClient.DeleteReview(ctx, owner, repoName, prNumber, posted.ID)
+	if err != nil {
+		t.Logf("Warning: could not delete test review %d: %v", posted.ID, err)
+	}
+}

cmd/review-bot/main.go

@@ -1,154 +1,402 @@
 package main
 
 import (
+	"context"
 	"flag"
 	"fmt"
-	"log"
+	"log/slog"
 	"os"
+	"path/filepath"
 	"strconv"
 	"strings"
+	"time"
 
+	"gitea.weiker.me/rodin/review-bot/budget"
 	"gitea.weiker.me/rodin/review-bot/gitea"
+	"gitea.weiker.me/rodin/review-bot/github"
 	"gitea.weiker.me/rodin/review-bot/llm"
 	"gitea.weiker.me/rodin/review-bot/review"
+	"gitea.weiker.me/rodin/review-bot/vcs"
 )
 
 var version = "dev"
 
+// setupLogger configures the global slog default logger based on format and verbosity.
+func setupLogger(format, verbosity string) {
+	var level slog.Level
+	switch strings.ToLower(verbosity) {
+	case "debug":
+		level = slog.LevelDebug
+	case "info":
+		level = slog.LevelInfo
+	case "warn":
+		level = slog.LevelWarn
+	case "error":
+		level = slog.LevelError
+	default:
+		level = slog.LevelInfo
+	}
+
+	opts := &slog.HandlerOptions{Level: level}
+
+	var handler slog.Handler
+	switch strings.ToLower(format) {
+	case "json":
+		handler = slog.NewJSONHandler(os.Stderr, opts)
+	default:
+		handler = slog.NewTextHandler(os.Stderr, opts)
+	}
+
+	slog.SetDefault(slog.New(handler))
+}
+
 func main() {
-	// CLI flags
-	giteaURL := flag.String("gitea-url", envOrDefault("GITEA_URL", ""), "Gitea instance URL")
-	repo := flag.String("repo", envOrDefault("GITEA_REPO", ""), "Repository (owner/name)")
+	versionFlag := flag.Bool("version", false, "Print version and exit")
+	// Logging flags
+	logFormat := flag.String("log-format", envOrDefault("LOG_FORMAT", "text"), "Log output format: text or json")
+	verbosity := flag.String("verbosity", envOrDefault("LOG_VERBOSITY", "info"), "Log verbosity: debug, info, warn, error")
+	// VCS flags
+	provider := flag.String("provider", envOrDefault("VCS_PROVIDER", "gitea"), "VCS provider: gitea or github")
+	baseURL := flag.String("base-url", envOrDefault("VCS_BASE_URL", ""), "VCS API base URL (for github provider; defaults to https://api.github.com)")
+	vcsURL := flag.String("vcs-url", envOrDefault("VCS_URL", envOrDefault("GITEA_URL", envOrDefault("GITHUB_SERVER_URL", ""))), "VCS instance URL (Gitea) [deprecated alias: --gitea-url]")
+	// Keep --gitea-url as backward-compatible alias (flag package doesn't support aliases natively, handle below)
+	repo := flag.String("repo", envOrDefault("VCS_REPO", envOrDefault("GITEA_REPO", envOrDefault("GITHUB_REPOSITORY", ""))), "Repository (owner/name)")
 	prNum := flag.String("pr", envOrDefault("PR_NUMBER", ""), "Pull request number")
 	reviewerName := flag.String("reviewer-name", envOrDefault("REVIEWER_NAME", ""), "Reviewer display name")
-	reviewerToken := flag.String("reviewer-token", envOrDefault("REVIEWER_TOKEN", ""), "Gitea token for posting review")
+	reviewerToken := flag.String("reviewer-token", envOrDefault("REVIEWER_TOKEN", ""), "VCS token for posting review")
 	llmBaseURL := flag.String("llm-base-url", envOrDefault("LLM_BASE_URL", ""), "LLM API base URL")
 	llmAPIKey := flag.String("llm-api-key", envOrDefault("LLM_API_KEY", ""), "LLM API key")
 	llmModel := flag.String("llm-model", envOrDefault("LLM_MODEL", ""), "LLM model name")
 	conventionsFile := flag.String("conventions-file", envOrDefault("CONVENTIONS_FILE", ""), "Conventions file path in repo (e.g. CLAUDE.md)")
+	systemPromptFile := flag.String("system-prompt-file", envOrDefault("SYSTEM_PROMPT_FILE", ""), "Local file with additional system prompt instructions")
 	patternsRepo := flag.String("patterns-repo", envOrDefault("PATTERNS_REPO", ""), "Repo with language patterns (e.g. rodin/elixir-patterns)")
 	patternsFiles := flag.String("patterns-files", envOrDefault("PATTERNS_FILES", "README.md"), "Comma-separated file paths to fetch from patterns repo")
 	dryRun := flag.Bool("dry-run", false, "Print review to stdout instead of posting")
 	llmTemp := flag.Float64("llm-temperature", envOrDefaultFloat("LLM_TEMPERATURE", 0), "LLM temperature (0 = server default)")
+	llmTimeout := flag.Int("llm-timeout", envOrDefaultInt("LLM_TIMEOUT", 300), "LLM request timeout in seconds (default 300)")
+	llmProvider := flag.String("llm-provider", envOrDefault("LLM_PROVIDER", "openai"), "LLM API provider: openai, anthropic, or aicore")
+	personaName := flag.String("persona", envOrDefault("PERSONA", ""), "Built-in persona name (security, architect, docs)")
+	personaFile := flag.String("persona-file", envOrDefault("PERSONA_FILE", ""), "Path to persona JSON file")
+	// AI Core specific flags (only used when provider=aicore)
+	aicoreClientID := flag.String("aicore-client-id", envOrDefault("AICORE_CLIENT_ID", ""), "SAP AI Core client ID (for provider=aicore)")
+	aicoreClientSecret := flag.String("aicore-client-secret", envOrDefault("AICORE_CLIENT_SECRET", ""), "SAP AI Core client secret (for provider=aicore)")
+	aicoreAuthURL := flag.String("aicore-auth-url", envOrDefault("AICORE_AUTH_URL", ""), "SAP AI Core auth URL (for provider=aicore)")
+	aicoreAPIURL := flag.String("aicore-api-url", envOrDefault("AICORE_API_URL", ""), "SAP AI Core API URL (for provider=aicore)")
+	aicoreResourceGroup := flag.String("aicore-resource-group", envOrDefault("AICORE_RESOURCE_GROUP", "default"), "SAP AI Core resource group (for provider=aicore)")
+
+	// Backward-compatible alias: --gitea-url shares vcsURL's pointer (last flag wins).
+	// Must use *vcsURL as default: StringVar sets *p=value at registration, so empty
+	// string would overwrite the env-resolved value from the --vcs-url declaration.
+	flag.StringVar(vcsURL, "gitea-url", *vcsURL, "Deprecated: use --vcs-url instead")
 
 	flag.Parse()
 
+	if *versionFlag {
+		fmt.Printf("review-bot %s\n", version)
+		os.Exit(0)
+	}
+
+	// Initialize structured logger
+	setupLogger(*logFormat, *verbosity)
+
+	slog.Info("review-bot starting", "version", version)
+
+	// Validate VCS provider
+	vcsProvider := vcs.VCSProvider(*provider)
+	if !vcsProvider.Valid() {
+		fmt.Fprintf(os.Stderr, "Error: invalid --provider %q (valid: gitea, github)\n", *provider)
+		os.Exit(1)
+	}
+
 	// Validate required fields
-	if *giteaURL == "" || *repo == "" || *prNum == "" || *reviewerToken == "" ||
-		*llmBaseURL == "" || *llmAPIKey == "" || *llmModel == "" {
+	isAICore := llm.Provider(*llmProvider) == llm.ProviderAICore
+	if *repo == "" || *prNum == "" || *reviewerToken == "" || *llmModel == "" {
 		fmt.Fprintf(os.Stderr, "Error: missing required flags or environment variables\n\n")
-		fmt.Fprintf(os.Stderr, "Required: --gitea-url, --repo, --pr, --reviewer-token, --llm-base-url, --llm-api-key, --llm-model\n")
+		fmt.Fprintf(os.Stderr, "Required: --repo, --pr, --reviewer-token, --llm-model\n")
+		os.Exit(1)
+	}
+	// --vcs-url is required only for gitea provider
+	if vcsProvider == vcs.ProviderGitea && *vcsURL == "" {
+		fmt.Fprintf(os.Stderr, "Error: --vcs-url (or --gitea-url) is required for provider=gitea\n")
+		os.Exit(1)
+	}
+	if !isAICore && (*llmBaseURL == "" || *llmAPIKey == "") {
+		fmt.Fprintf(os.Stderr, "Error: --llm-base-url and --llm-api-key are required for provider=%s\n", *llmProvider)
+		os.Exit(1)
+	}
+	if isAICore && (*aicoreClientID == "" || *aicoreClientSecret == "" || *aicoreAuthURL == "" || *aicoreAPIURL == "") {
+		fmt.Fprintf(os.Stderr, "Error: AI Core credentials required for provider=aicore\n\n")
+		fmt.Fprintf(os.Stderr, "Required: --aicore-client-id, --aicore-client-secret, --aicore-auth-url, --aicore-api-url\n")
+		os.Exit(1)
+	}
+
+	// Validate persona flags are mutually exclusive
+	if *personaName != "" && *personaFile != "" {
+		slog.Error("--persona and --persona-file are mutually exclusive")
+		os.Exit(1)
+	}
+
+	// Validate reviewer-name: only safe characters allowed in sentinel
+	if err := validateReviewerName(*reviewerName); err != nil {
+		slog.Error("invalid reviewer name", "error", err)
 		os.Exit(1)
 	}
 
 	// Parse repo owner/name
 	parts := strings.SplitN(*repo, "/", 2)
 	if len(parts) != 2 {
-		log.Fatalf("Invalid repo format %q, expected owner/name", *repo)
+		slog.Error("invalid repo format", "repo", *repo, "expected", "owner/name")
+		os.Exit(1)
 	}
 	owner, repoName := parts[0], parts[1]
 
 	// Parse PR number
 	prNumber, err := strconv.Atoi(*prNum)
 	if err != nil {
-		log.Fatalf("Invalid PR number %q: %v", *prNum, err)
+		slog.Error("invalid PR number", "pr", *prNum, "error", err)
+		os.Exit(1)
 	}
 
-	// Initialize clients
-	giteaClient := gitea.NewClient(*giteaURL, *reviewerToken)
+	// Initialize VCS client
+	var client vcs.Client
+	switch vcsProvider {
+	case vcs.ProviderGitea:
+		giteaClient := gitea.NewClient(*vcsURL, *reviewerToken)
+		client = gitea.NewAdapter(giteaClient)
+	case vcs.ProviderGitHub:
+		client = github.NewClient(*reviewerToken, *baseURL)
+	default:
+		panic("unreachable: provider validation should have caught " + vcsProvider.String())
+	}
+	slog.Info("VCS client initialized", "provider", vcsProvider)
+
+	// Initialize LLM client
 	llmClient := llm.NewClient(*llmBaseURL, *llmAPIKey, *llmModel)
 	if *llmTemp < 0 || *llmTemp > 2 {
-		log.Fatal("--llm-temperature must be between 0 and 2")
+		slog.Error("invalid LLM temperature", "temperature", *llmTemp, "range", "0-2")
+		os.Exit(1)
 	}
 	if *llmTemp > 0 {
 		llmClient.WithTemperature(*llmTemp)
 	}
+	switch llm.Provider(*llmProvider) {
+	case llm.ProviderOpenAI, llm.ProviderAnthropic:
+		llmClient.WithProvider(llm.Provider(*llmProvider))
+	case llm.ProviderAICore:
+		llmClient.WithAICore(llm.AICoreConfig{
+			ClientID:      *aicoreClientID,
+			ClientSecret:  *aicoreClientSecret,
+			AuthURL:       *aicoreAuthURL,
+			APIURL:        *aicoreAPIURL,
+			ResourceGroup: *aicoreResourceGroup,
+		})
+		slog.Info("using SAP AI Core provider", "resource_group", *aicoreResourceGroup)
+	default:
+		slog.Error("invalid LLM provider", "provider", *llmProvider, "valid", "openai, anthropic, aicore")
+		os.Exit(1)
+	}
+	if *llmTimeout > 0 {
+		llmClient.WithTimeout(time.Duration(*llmTimeout) * time.Second)
+	}
 
-	log.Printf("Reviewing PR #%d on %s/%s", prNumber, owner, repoName)
+	// Create a top-level context. Timeout derived from LLM timeout + 1 min for other ops.
+	overallTimeout := time.Duration(*llmTimeout)*time.Second + time.Minute
+	ctx, cancel := context.WithTimeout(context.Background(), overallTimeout)
+	defer cancel()
+
+	// Load persona if specified
+	var persona *review.Persona
+	if *personaName != "" {
+		// Try loading from repo first, then fall back to built-in
+		repoPersonas, err := review.LoadRepoPersonas(ctx, client, owner, repoName)
+		if err != nil {
+			slog.Warn("could not load repo personas", "repo", owner+"/"+repoName, "error", err)
+		}
+		if p, ok := repoPersonas[*personaName]; ok {
+			persona = p
+			slog.Info("loaded repo persona", "persona", persona.Name, "display", persona.DisplayName, "repo", owner+"/"+repoName)
+		} else {
+			// Fall back to built-in
+			persona, err = review.LoadBuiltinPersona(*personaName)
+			if err != nil {
+				slog.Error("failed to load persona", "persona", *personaName, "error", err)
+				os.Exit(1)
+			}
+			slog.Info("loaded built-in persona", "persona", persona.Name, "display", persona.DisplayName)
+		}
+	} else if *personaFile != "" {
+		resolvedPath, err := validateWorkspacePath(*personaFile, "persona-file")
+		if err != nil {
+			slog.Error("invalid persona-file path", "error", err)
+			os.Exit(1)
+		}
+		persona, err = review.LoadPersona(resolvedPath)
+		if err != nil {
+			slog.Error("failed to load persona file", "file", *personaFile, "error", err)
+			os.Exit(1)
+		}
+		slog.Info("loaded persona from file", "file", *personaFile, "persona", persona.Name)
+	}
+
+	slog.Info("reviewing pull request", "pr", prNumber, "repo", fmt.Sprintf("%s/%s", owner, repoName))
 
 	// Step 1: Fetch PR metadata
-	pr, err := giteaClient.GetPullRequest(owner, repoName, prNumber)
+	pr, err := client.GetPullRequest(ctx, owner, repoName, prNumber)
 	if err != nil {
-		log.Fatalf("Failed to fetch PR: %v", err)
+		slog.Error("failed to fetch PR", "pr", prNumber, "error", err)
+		os.Exit(1)
 	}
-	log.Printf("PR: %s", pr.Title)
+	slog.Info("fetched PR metadata", "pr", prNumber, "title", pr.Title)
 
 	// Step 2: Fetch diff
-	diff, err := giteaClient.GetPullRequestDiff(owner, repoName, prNumber)
+	diff, err := client.GetPullRequestDiff(ctx, owner, repoName, prNumber)
 	if err != nil {
-		log.Fatalf("Failed to fetch diff: %v", err)
+		slog.Error("failed to fetch diff", "pr", prNumber, "error", err)
+		os.Exit(1)
 	}
-	log.Printf("Diff size: %d bytes", len(diff))
+	slog.Info("fetched diff", "bytes", len(diff))
 
 	// Step 3: Fetch full file content for modified files
 	fileContext := ""
-	files, err := giteaClient.GetPullRequestFiles(owner, repoName, prNumber)
+	files, err := client.GetPullRequestFiles(ctx, owner, repoName, prNumber)
 	if err != nil {
-		log.Printf("Warning: could not fetch PR files list: %v", err)
+		slog.Warn("could not fetch PR files list", "pr", prNumber, "error", err)
 	} else {
-		fileContext = fetchFileContext(giteaClient, owner, repoName, pr.Head.Ref, files)
-		log.Printf("Fetched full context for %d files", len(files))
+		fileContext = fetchFileContext(ctx, client, owner, repoName, pr.Head.Ref, files)
+		slog.Debug("fetched file context", "files", len(files))
 	}
 
 	// Step 4: Check CI status
 	ciPassed := true
 	ciDetails := ""
-	if pr.Head.Sha != "" {
-		statuses, err := giteaClient.GetCommitStatuses(owner, repoName, pr.Head.Sha)
+	if pr.Head.SHA != "" {
+		statuses, err := client.GetCommitStatuses(ctx, owner, repoName, pr.Head.SHA)
 		if err != nil {
-			log.Printf("Warning: could not fetch CI status: %v", err)
+			slog.Warn("could not fetch CI status", "sha", pr.Head.SHA, "error", err)
 		} else {
 			ciPassed, ciDetails = evaluateCIStatus(statuses)
-			log.Printf("CI status: passed=%v", ciPassed)
+			slog.Info("CI status checked", "passed", ciPassed)
 		}
 	}
 
 	// Step 5: Load conventions file if specified
 	conventions := ""
 	if *conventionsFile != "" {
-		content, err := giteaClient.GetFileContent(owner, repoName, *conventionsFile)
+		content, err := client.GetFileContent(ctx, owner, repoName, *conventionsFile, "")
 		if err != nil {
-			log.Printf("Warning: could not load conventions file %q: %v", *conventionsFile, err)
+			slog.Warn("could not load conventions file", "file", *conventionsFile, "error", err)
 		} else {
 			conventions = content
-			log.Printf("Loaded conventions file: %s (%d bytes)", *conventionsFile, len(conventions))
+			slog.Debug("loaded conventions file", "file", *conventionsFile, "bytes", len(conventions))
 		}
 	}
 
 	// Step 6: Load patterns from external repo if specified
 	patterns := ""
 	if *patternsRepo != "" {
-		patterns = fetchPatterns(giteaClient, *patternsRepo, *patternsFiles)
-		log.Printf("Loaded patterns from %s (%d bytes)", *patternsRepo, len(patterns))
+		patterns = fetchPatterns(ctx, client, *patternsRepo, *patternsFiles)
+		slog.Debug("loaded patterns", "repo", *patternsRepo, "bytes", len(patterns))
 	}
 
-	// Step 7: Build prompts
-	systemPrompt := review.BuildSystemPrompt(conventions, patterns)
-	userPrompt := review.BuildUserPrompt(pr.Title, pr.Body, diff, fileContext, ciPassed, ciDetails)
+	// Step 6b: Load additional system prompt if specified
+	additionalPrompt := ""
+	if *systemPromptFile != "" {
+		resolvedPath, err := validateWorkspacePath(*systemPromptFile, "system-prompt-file")
+		if err != nil {
+			slog.Error("invalid system-prompt-file path", "error", err)
+			os.Exit(1)
+		}
+		data, err := os.ReadFile(resolvedPath)
+		if err != nil {
+			slog.Error("failed to read system prompt file", "path", *systemPromptFile, "error", err)
+			os.Exit(1)
+		}
+		additionalPrompt = string(data)
+		slog.Debug("loaded system prompt file", "file", *systemPromptFile, "bytes", len(additionalPrompt))
+	}
 
-	// Step 8: Call LLM
-	log.Printf("Sending to LLM (%s)...", *llmModel)
+	// Step 7: Budget-aware prompt assembly
+	var systemBase string
+	if persona != nil {
+		systemBase = review.BuildPersonaSystemPrompt(persona)
+		slog.Debug("using persona system prompt", "persona", persona.Name)
+	} else {
+		systemBase = review.BuildSystemBase()
+	}
+	if additionalPrompt != "" {
+		systemBase += "\n\n## Additional Review Instructions\n\n" + additionalPrompt
+	}
+	sections := budget.Sections{
+		SystemBase:  systemBase,
+		Patterns:    patterns,
+		Conventions: conventions,
+		FileContext: fileContext,
+		Diff:        diff,
+		UserMeta:    review.BuildUserMeta(pr.Title, pr.Body, ciPassed, ciDetails),
+	}
+	budgetResult := budget.Fit(*llmModel, sections)
+	slog.Info("token budget calculated", "tokens", budgetResult.EstTokens, "limit", budget.LimitForModel(*llmModel), "model", *llmModel)
+	if len(budgetResult.Trimmed) > 0 {
+		slog.Warn("context trimmed to fit budget", "trimmed", budgetResult.Trimmed)
+	}
+
+	// Step 8: Call LLM (with retry on parse failure)
+	slog.Info("sending request to LLM", "model", *llmModel)
 	messages := []llm.Message{
-		{Role: "system", Content: systemPrompt},
-		{Role: "user", Content: userPrompt},
+		{Role: "system", Content: budgetResult.SystemPrompt},
+		{Role: "user", Content: budgetResult.UserPrompt},
 	}
 
-	response, err := llmClient.Complete(messages)
-	if err != nil {
-		log.Fatalf("LLM request failed: %v", err)
-	}
-	log.Printf("LLM response received (%d bytes)", len(response))
+	var response string
+	var result *review.ReviewResult
+	for attempt := 1; attempt <= 2; attempt++ {
+		if attempt > 1 {
+			slog.Warn("retrying LLM request after parse failure", "attempt", attempt)
+			time.Sleep(time.Second)
+		}
 
-	// Step 9: Parse response
-	result, err := review.ParseResponse(response)
-	if err != nil {
-		log.Fatalf("Failed to parse LLM response: %v", err)
+		response, err = llmClient.Complete(ctx, messages)
+		if err != nil {
+			slog.Error("LLM request failed", "model", *llmModel, "error", err, "attempt", attempt)
+			if attempt == 2 {
+				os.Exit(1)
+			}
+			continue
+		}
+		slog.Info("LLM response received", "bytes", len(response), "attempt", attempt)
+
+		// Step 9: Parse response
+		result, err = review.ParseResponse(response)
+		if err != nil {
+			slog.Error("failed to parse LLM response", "error", err, "attempt", attempt)
+			if attempt == 2 {
+				os.Exit(1)
+			}
+			continue
+		}
+		break
 	}
-	log.Printf("Verdict: %s (%d findings)", result.Verdict, len(result.Findings))
+	slog.Info("review parsed", "verdict", result.Verdict, "findings", len(result.Findings))
 
 	// Step 10: Format and post review
-	reviewBody := review.FormatMarkdown(result, *reviewerName)
-	event := review.GiteaEvent(result.Verdict)
+	var reviewBody string
+	if persona != nil && persona.DisplayName != "" {
+		reviewBody = review.FormatMarkdownWithDisplay(result, persona.DisplayName, *reviewerName)
+	} else {
+		reviewBody = review.FormatMarkdown(result, *reviewerName)
+	}
+
+	// Add commit footer so readers know which commit was evaluated
+	if pr.Head.SHA != "" {
+		shortSHA := pr.Head.SHA
+		if len(shortSHA) > 8 {
+			shortSHA = shortSHA[:8]
+		}
+		reviewBody += fmt.Sprintf("\n\n---\n*Evaluated against %s*", shortSHA)
+	}
+
+	// Map verdict to canonical review event
+	event := verdictToEvent(result.Verdict)
 
 	if *dryRun {
 		fmt.Println("--- DRY RUN ---")
@@ -157,23 +405,134 @@ func main() {
 		return
 	}
 
-	log.Printf("Posting review (event=%s)...", event)
-	if err := giteaClient.PostReview(owner, repoName, prNumber, event, reviewBody); err != nil {
-		log.Fatalf("Failed to post review: %v", err)
+	sentinel := fmt.Sprintf("<!-- review-bot:%s -->", *reviewerName)
+
+	// Stale check: verify HEAD hasn't moved since we started
+	evaluatedSHA := pr.Head.SHA
+	var currentSHA string
+	currentPR, err := client.GetPullRequest(ctx, owner, repoName, prNumber)
+	if err != nil {
+		slog.Warn("could not re-fetch PR for stale check", "pr", prNumber, "error", err)
+	} else {
+		currentSHA = currentPR.Head.SHA
+	}
+	if shouldSkipStaleReview(evaluatedSHA, currentSHA) {
+		slog.Warn("HEAD moved during review -- skipping stale review",
+			"evaluated", evaluatedSHA,
+			"current", currentSHA,
+			"pr", prNumber)
+		return
+	}
+
+	// Build line→position map for inline comments
+	lineToPosition := vcs.BuildLineToPositionMap(diff)
+	var inlineComments []vcs.ReviewComment
+	for _, f := range result.Findings {
+		if f.File == "" || f.Line <= 0 {
+			continue
+		}
+		pos, ok := lineToPosition[f.File][f.Line]
+		if !ok {
+			slog.Warn("line not in diff, skipping comment", "file", f.File, "line", f.Line)
+			continue
+		}
+		inlineComments = append(inlineComments, vcs.ReviewComment{
+			Path:     f.File,
+			Position: pos,
+			CommitID: evaluatedSHA,
+			Body:     fmt.Sprintf("**[%s]** %s", f.Severity, f.Finding),
+		})
+	}
+	if len(inlineComments) > 0 {
+		slog.Debug("attaching inline comments", "count", len(inlineComments))
+	}
+
+	// --- Review update strategy ---
+	// 1. POST new review first (gets non-stale approval badge on HEAD)
+	// 2. Then supersede old review with link to the new one
+	var oldReviews []vcs.Review
+	if *reviewerName != "" {
+		existingReviews, err := client.ListReviews(ctx, owner, repoName, prNumber)
+		if err != nil {
+			slog.Warn("could not list existing reviews", "pr", prNumber, "error", err)
+		} else {
+			if hasSharedToken(existingReviews, sentinel) {
+				slog.Warn("shared token mode: skipping supersede to avoid clobbering sibling review")
+			} else {
+				oldReviews = findAllOwnReviews(existingReviews, sentinel)
+			}
+		}
+	}
+
+	// Self-request as reviewer (Gitea-specific; ensures we appear in required-reviewer checks)
+	if selfReq, ok := client.(vcs.ReviewerSelfRequester); ok {
+		authUser, err := client.GetAuthenticatedUser(ctx)
+		if err != nil {
+			slog.Warn("could not determine authenticated user for reviewer self-request", "error", err)
+		} else if authUser != "" {
+			if err := selfReq.RequestReviewerSelf(ctx, owner, repoName, prNumber, authUser); err != nil {
+				slog.Warn("could not self-request as reviewer", "user", authUser, "error", err)
+			} else {
+				slog.Debug("self-requested as reviewer", "user", authUser, "pr", prNumber)
+			}
+		}
+	} else {
+		slog.Debug("RequestReviewer not supported for provider, skipping")
+	}
+
+	// POST new review
+	slog.Info("posting review", "event", event, "pr", prNumber)
+	reviewReq := vcs.ReviewRequest{
+		Body:     reviewBody,
+		Event:    event,
+		CommitID: evaluatedSHA,
+		Comments: inlineComments,
+	}
+	posted, err := client.PostReview(ctx, owner, repoName, prNumber, reviewReq)
+	if err != nil {
+		slog.Error("failed to post review", "pr", prNumber, "event", event, "error", err)
+		os.Exit(1)
+	}
+	slog.Info("review posted", "review_id", posted.ID, "user", posted.User.Login, "pr", prNumber)
+
+	// Supersede all old reviews via optional interface
+	if len(oldReviews) > 0 {
+		if superseder, ok := client.(vcs.ReviewSuperseder); ok {
+			if err := superseder.SupersedeReviews(ctx, owner, repoName, prNumber, oldReviews, posted.ID, *vcsURL, sentinel); err != nil {
+				slog.Error("failed to supersede old reviews", "error", err)
+				os.Exit(1)
+			}
+		} else {
+			slog.Error("provider does not support review superseding", "provider", vcsProvider)
+		}
+	}
+}
+
+// verdictToEvent maps a verdict string from the LLM response to a canonical vcs.ReviewEvent.
+func verdictToEvent(verdict string) vcs.ReviewEvent {
+	switch verdict {
+	case "APPROVE":
+		return vcs.ReviewEventApprove
+	case "REQUEST_CHANGES":
+		return vcs.ReviewEventRequestChanges
+	default:
+		return vcs.ReviewEventComment
 	}
-	log.Printf("Review posted successfully!")
 }
 
 // fetchFileContext fetches the full content of modified files from the PR branch.
-func fetchFileContext(client *gitea.Client, owner, repo, ref string, files []gitea.ChangedFile) string {
+func fetchFileContext(ctx context.Context, client vcs.PRReader, owner, repo, ref string, files []vcs.ChangedFile) string {
 	var sb strings.Builder
 	for _, f := range files {
+		if ctx.Err() != nil {
+			break
+		}
 		if f.Status == "removed" {
 			continue // Skip deleted files
 		}
-		content, err := client.GetFileContentRef(owner, repo, f.Filename, ref)
+		content, err := client.GetFileContentAtRef(ctx, owner, repo, f.Filename, ref)
 		if err != nil {
-			log.Printf("Warning: could not fetch %s: %v", f.Filename, err)
+			slog.Warn("could not fetch file content", "file", f.Filename, "error", err)
 			continue
 		}
 		sb.WriteString(fmt.Sprintf("--- %s ---\n", f.Filename))
@@ -188,44 +547,62 @@ func fetchFileContext(client *gitea.Client, owner, repo, ref string, files []git
 // patternsRepo is comma-separated list of owner/name repos.
 // patternsFiles is comma-separated list of file paths or directories.
 // If a path ends with / or is a directory, all files within it are fetched recursively.
-func fetchPatterns(client *gitea.Client, patternsRepo, patternsFiles string) string {
+// Empty entries in patternsFiles are skipped (no implicit repo-root fetch).
+func fetchPatterns(ctx context.Context, client vcs.FileReader, patternsRepo, patternsFiles string) string {
 	var sb strings.Builder
 
 	repos := strings.Split(patternsRepo, ",")
 	paths := strings.Split(patternsFiles, ",")
 
 	for _, repoRef := range repos {
+		if ctx.Err() != nil {
+			break
+		}
 		repoRef = strings.TrimSpace(repoRef)
 		if repoRef == "" {
 			continue
 		}
 		parts := strings.SplitN(repoRef, "/", 2)
 		if len(parts) != 2 {
-			log.Printf("Warning: invalid patterns-repo format %q, expected owner/name", repoRef)
+			slog.Warn("invalid patterns-repo format", "repo", repoRef, "expected", "owner/name")
 			continue
 		}
 		owner, repo := parts[0], parts[1]
 
+		var repoLoadedFiles []string
+		var repoSkippedFiles []string
+
 		for _, path := range paths {
 			path = strings.TrimSpace(path)
 			if path == "" {
 				continue
 			}
 
-			files, err := client.GetAllFilesInPath(owner, repo, path)
+			files, err := vcs.GetAllFilesInPath(ctx, client, owner, repo, path)
 			if err != nil {
-				log.Printf("Warning: could not fetch %s from %s: %v", path, repoRef, err)
+				slog.Warn("could not fetch patterns", "path", path, "repo", repoRef, "error", err)
 				continue
 			}
 
-			for filepath, content := range files {
+			for filePath, content := range files {
 				// Only include markdown and text files as patterns
-				if !isPatternFile(filepath) {
+				if !isPatternFile(filePath) {
+					repoSkippedFiles = append(repoSkippedFiles, filePath)
 					continue
 				}
-				sb.WriteString(fmt.Sprintf("### %s/%s\n\n%s\n\n", repoRef, filepath, content))
+				repoLoadedFiles = append(repoLoadedFiles, filePath)
+				sb.WriteString(fmt.Sprintf("### %s/%s\n\n%s\n\n", repoRef, filePath, content))
 			}
 		}
+
+		if len(repoLoadedFiles) > 0 {
+			slog.Info("loaded pattern files", "repo", repoRef, "count", len(repoLoadedFiles), "files", repoLoadedFiles)
+		} else {
+			slog.Warn("no pattern files loaded", "repo", repoRef, "paths", paths)
+		}
+		if len(repoSkippedFiles) > 0 {
+			slog.Debug("skipped non-pattern files", "repo", repoRef, "count", len(repoSkippedFiles), "files", repoSkippedFiles)
+		}
 	}
 	return sb.String()
 }
@@ -240,18 +617,20 @@ func isPatternFile(path string) bool {
 }
 
 // evaluateCIStatus checks if all CI statuses indicate success.
-func evaluateCIStatus(statuses []gitea.CommitStatus) (passed bool, details string) {
+// Returns passed=true if no checks have failed (pending checks are not treated as failures).
+func evaluateCIStatus(statuses []vcs.CommitStatus) (passed bool, details string) {
 	if len(statuses) == 0 {
 		return true, "no CI statuses found"
 	}
 
 	var failed []string
+	var pending int
 	for _, s := range statuses {
 		switch s.Status {
 		case "success":
 			// good
 		case "pending":
-			// treat pending as not-failed
+			pending++
 		case "failure", "error":
 			failed = append(failed, fmt.Sprintf("%s: %s", s.Context, s.Description))
 		}
@@ -260,6 +639,9 @@ func evaluateCIStatus(statuses []gitea.CommitStatus) (passed bool, details strin
 	if len(failed) > 0 {
 		return false, strings.Join(failed, "; ")
 	}
+	if pending > 0 {
+		return true, fmt.Sprintf("no failures (%d pending)", pending)
+	}
 	return true, "all checks passed"
 }
 
@@ -279,3 +661,147 @@ func envOrDefaultFloat(key string, defaultVal float64) float64 {
 	}
 	return defaultVal
 }
+
+func envOrDefaultInt(key string, defaultVal int) int {
+	if v := os.Getenv(key); v != "" {
+		i, err := strconv.Atoi(v)
+		if err == nil {
+			return i
+		}
+	}
+	return defaultVal
+}
+
+// validateReviewerName checks that the name contains only safe characters
+// for embedding in an HTML comment sentinel ([a-zA-Z0-9_-]).
+func validateReviewerName(name string) error {
+	if name == "" {
+		return nil
+	}
+	for _, ch := range name {
+		if !((ch >= 'a' && ch <= 'z') || (ch >= 'A' && ch <= 'Z') || (ch >= '0' && ch <= '9') || ch == '-' || ch == '_') {
+			return fmt.Errorf("reviewer-name must contain only [a-zA-Z0-9_-] (got %q)", name)
+		}
+	}
+	return nil
+}
+
+// validateWorkspacePath ensures a file path is within the workspace and resolves
+// symlinks to prevent traversal attacks. Returns the resolved absolute path or
+// an error if the path is outside the workspace.
+func validateWorkspacePath(path, pathName string) (string, error) {
+	workspace := os.Getenv("GITHUB_WORKSPACE")
+	if workspace == "" {
+		workspace, _ = os.Getwd()
+	}
+	absWorkspace, err := filepath.Abs(workspace)
+	if err != nil {
+		return "", fmt.Errorf("failed to resolve workspace path: %w", err)
+	}
+
+	// Join and clean the path
+	fullPath := filepath.Join(absWorkspace, path)
+	fullPath = filepath.Clean(fullPath)
+
+	// Check path is within workspace using filepath.Rel (more robust than HasPrefix)
+	rel, err := filepath.Rel(absWorkspace, fullPath)
+	if err != nil || strings.HasPrefix(rel, "..") {
+		return "", fmt.Errorf("%s resolves outside workspace: path=%s workspace=%s", pathName, fullPath, absWorkspace)
+	}
+
+	// Resolve symlinks and re-validate to prevent symlink traversal
+	resolvedPath, err := filepath.EvalSymlinks(fullPath)
+	if err != nil {
+		return "", fmt.Errorf("failed to resolve %s: %w", pathName, err)
+	}
+
+	relResolved, err := filepath.Rel(absWorkspace, resolvedPath)
+	if err != nil || strings.HasPrefix(relResolved, "..") {
+		return "", fmt.Errorf("%s symlink resolves outside workspace: resolved=%s workspace=%s", pathName, resolvedPath, absWorkspace)
+	}
+
+	return resolvedPath, nil
+}
+
+// hasSharedToken detects if another review-bot role posted under the same
+// VCS user. This indicates misconfiguration where two roles share a token
+// instead of having separate accounts. Returns true if shared token
+// detected (caller should skip update-in-place logic to avoid clobbering).
+func hasSharedToken(reviews []vcs.Review, ownSentinel string) bool {
+	ownLogin := ""
+	for _, r := range reviews {
+		if strings.Contains(r.Body, ownSentinel) {
+			ownLogin = r.User.Login
+			break
+		}
+	}
+	if ownLogin == "" {
+		return false
+	}
+	for _, r := range reviews {
+		if r.User.Login == ownLogin && strings.Contains(r.Body, "<!-- review-bot:") && !strings.Contains(r.Body, ownSentinel) {
+			slog.Warn("shared token detected -- another review-bot role is using the same VCS user",
+				"sibling_role", extractSentinelName(r.Body), "user", ownLogin)
+			return true
+		}
+	}
+	return false
+}
+
+// extractSentinelName pulls the reviewer name from a sentinel comment.
+func extractSentinelName(body string) string {
+	const prefix = "<!-- review-bot:"
+	const suffix = " -->"
+	idx := strings.Index(body, prefix)
+	if idx < 0 {
+		return "unknown"
+	}
+	rest := body[idx+len(prefix):]
+	end := strings.Index(rest, suffix)
+	if end < 0 {
+		return "unknown"
+	}
+	name := rest[:end]
+	// Sanitize: strip control characters to prevent log injection.
+	name = strings.Map(func(r rune) rune {
+		if r < 0x20 || r == 0x7f {
+			return -1
+		}
+		return r
+	}, name)
+	if len(name) > 64 {
+		name = name[:64]
+	}
+	if name == "" {
+		return "unknown"
+	}
+	return name
+}
+
+// findAllOwnReviews returns all non-superseded reviews matching the sentinel.
+func findAllOwnReviews(reviews []vcs.Review, sentinel string) []vcs.Review {
+	var result []vcs.Review
+	for i := range reviews {
+		if !strings.Contains(reviews[i].Body, sentinel) {
+			continue
+		}
+		if strings.Contains(reviews[i].Body, "~~Original review~~") {
+			continue
+		}
+		result = append(result, reviews[i])
+	}
+	return result
+}
+
+// shouldSkipStaleReview reports whether to skip posting because HEAD moved.
+// Returns true (skip) if evaluatedSHA differs from currentSHA.
+// Returns false (don't skip) if:
+//   - SHAs match (no movement)
+//   - currentSHA is empty (re-fetch failed; prefer posting stale over failing)
+func shouldSkipStaleReview(evaluatedSHA, currentSHA string) bool {
+	if currentSHA == "" {
+		// Re-fetch failed; better to post potentially stale than fail
+		return false
+	}
+	return evaluatedSHA != currentSHA
+}

cmd/review-bot/main_test.go

@@ -0,0 +1,893 @@
+package main
+
+import (
+	"bytes"
+	"flag"
+	"log/slog"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"gitea.weiker.me/rodin/review-bot/vcs"
+)
+
+func TestValidateReviewerName(t *testing.T) {
+	tests := []struct {
+		name    string
+		input   string
+		wantErr bool
+	}{
+		{"valid simple", "sonnet", false},
+		{"valid with dash", "code-review", false},
+		{"valid with underscore", "my_bot", false},
+		{"valid alphanumeric", "bot123", false},
+		{"valid uppercase", "MyBot", false},
+		{"empty is valid", "", false},
+		{"invalid html close", "foo-->", true},
+		{"invalid space", "my bot", true},
+		{"invalid dot", "my.bot", true},
+		{"invalid slash", "my/bot", true},
+		{"invalid angle", "bot<script>", true},
+		{"invalid colon", "bot:name", true},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			err := validateReviewerName(tc.input)
+			if tc.wantErr && err == nil {
+				t.Errorf("expected error for %q, got nil", tc.input)
+			}
+			if !tc.wantErr && err != nil {
+				t.Errorf("expected no error for %q, got %v", tc.input, err)
+			}
+		})
+	}
+}
+
+func TestValidateWorkspacePath(t *testing.T) {
+	// Create a temp directory as our workspace
+	tmpDir := t.TempDir()
+
+	// Create a valid file inside the workspace
+	validFile := filepath.Join(tmpDir, "valid.json")
+	if err := os.WriteFile(validFile, []byte("{}"), 0644); err != nil {
+		t.Fatalf("failed to create test file: %v", err)
+	}
+
+	// Create a subdirectory with a file
+	subDir := filepath.Join(tmpDir, "subdir")
+	if err := os.MkdirAll(subDir, 0755); err != nil {
+		t.Fatalf("failed to create subdir: %v", err)
+	}
+	nestedFile := filepath.Join(subDir, "nested.json")
+	if err := os.WriteFile(nestedFile, []byte("{}"), 0644); err != nil {
+		t.Fatalf("failed to create nested file: %v", err)
+	}
+
+	// Create a symlink pointing outside the workspace
+	symlinkPath := filepath.Join(tmpDir, "evil-symlink.json")
+	if err := os.Symlink("/etc/passwd", symlinkPath); err != nil {
+		t.Fatalf("failed to create symlink: %v", err)
+	}
+
+	// Save and restore GITHUB_WORKSPACE
+	origWorkspace := os.Getenv("GITHUB_WORKSPACE")
+	defer os.Setenv("GITHUB_WORKSPACE", origWorkspace)
+
+	tests := []struct {
+		name      string
+		workspace string
+		path      string
+		wantErr   bool
+		errMatch  string
+	}{
+		{
+			name:      "valid relative path",
+			workspace: tmpDir,
+			path:      "valid.json",
+			wantErr:   false,
+		},
+		{
+			name:      "valid nested path",
+			workspace: tmpDir,
+			path:      "subdir/nested.json",
+			wantErr:   false,
+		},
+		{
+			name:      "path traversal attempt",
+			workspace: tmpDir,
+			path:      "../../../etc/passwd",
+			wantErr:   true,
+			errMatch:  "resolves outside workspace",
+		},
+		{
+			name:      "absolute path normalized to workspace-relative",
+			workspace: tmpDir,
+			path:      "/etc/passwd",
+			wantErr:   true,
+			errMatch:  "failed to resolve",
+		},
+		{
+			name:      "nonexistent file",
+			workspace: tmpDir,
+			path:      "nonexistent.json",
+			wantErr:   true,
+			errMatch:  "failed to resolve",
+		},
+		{
+			name:      "symlink escaping workspace",
+			workspace: tmpDir,
+			path:      "evil-symlink.json",
+			wantErr:   true,
+			errMatch:  "symlink resolves outside workspace",
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			os.Setenv("GITHUB_WORKSPACE", tc.workspace)
+			resolved, err := validateWorkspacePath(tc.path, "test-file")
+
+			if tc.wantErr {
+				if err == nil {
+					t.Errorf("expected error for %q, got nil", tc.path)
+				} else if tc.errMatch != "" && !strings.Contains(err.Error(), tc.errMatch) {
+					t.Errorf("error %q should contain %q", err.Error(), tc.errMatch)
+				}
+			} else {
+				if err != nil {
+					t.Errorf("expected no error for %q, got %v", tc.path, err)
+				}
+				if resolved == "" {
+					t.Error("expected non-empty resolved path")
+				}
+				// Verify resolved path is within workspace
+				if !strings.HasPrefix(resolved, tc.workspace) {
+					t.Errorf("resolved path %q not within workspace %q", resolved, tc.workspace)
+				}
+			}
+		})
+	}
+}
+
+func makeReview(id int64, login, state string, stale bool, body string) vcs.Review {
+	return vcs.Review{
+		ID:    id,
+		Body:  body,
+		User:  vcs.UserInfo{Login: login},
+		State: state,
+		Stale: stale,
+	}
+}
+
+func TestHasSharedToken(t *testing.T) {
+	tests := []struct {
+		name     string
+		reviews  []vcs.Review
+		sentinel string
+		want     bool
+	}{
+		{
+			name:     "no reviews",
+			reviews:  nil,
+			sentinel: "<!-- review-bot:sonnet -->",
+			want:     false,
+		},
+		{
+			name: "no own review yet - cannot detect",
+			reviews: []vcs.Review{
+				makeReview(1, "other", "APPROVED", false, "<!-- review-bot:gpt --> body"),
+			},
+			sentinel: "<!-- review-bot:sonnet -->",
+			want:     false,
+		},
+		{
+			name: "separate users - no shared token",
+			reviews: []vcs.Review{
+				makeReview(1, "sonnet-review-bot", "APPROVED", false, "<!-- review-bot:sonnet --> body"),
+				makeReview(2, "security-review-bot", "APPROVED", false, "<!-- review-bot:security --> body"),
+			},
+			sentinel: "<!-- review-bot:sonnet -->",
+			want:     false,
+		},
+		{
+			name: "shared token detected - same user different sentinels",
+			reviews: []vcs.Review{
+				makeReview(1, "sonnet-review-bot", "APPROVED", false, "<!-- review-bot:sonnet --> body"),
+				makeReview(2, "sonnet-review-bot", "APPROVED", false, "<!-- review-bot:security --> body"),
+			},
+			sentinel: "<!-- review-bot:sonnet -->",
+			want:     true,
+		},
+		{
+			name: "three roles same user",
+			reviews: []vcs.Review{
+				makeReview(1, "bot", "APPROVED", false, "<!-- review-bot:sonnet --> body"),
+				makeReview(2, "bot", "APPROVED", false, "<!-- review-bot:security --> body"),
+				makeReview(3, "bot", "APPROVED", false, "<!-- review-bot:gpt --> body"),
+			},
+			sentinel: "<!-- review-bot:sonnet -->",
+			want:     true,
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			got := hasSharedToken(tc.reviews, tc.sentinel)
+			if got != tc.want {
+				t.Errorf("hasSharedToken() = %v, want %v", got, tc.want)
+			}
+		})
+	}
+}
+
+func TestExtractSentinelName(t *testing.T) {
+	tests := []struct {
+		body string
+		want string
+	}{
+		{"<!-- review-bot:sonnet --> rest", "sonnet"},
+		{"<!-- review-bot:security --> rest", "security"},
+		{"no sentinel here", "unknown"},
+		{"<!-- review-bot:gpt-review --> rest", "gpt-review"},
+	}
+
+	for _, tc := range tests {
+		got := extractSentinelName(tc.body)
+		if got != tc.want {
+			t.Errorf("extractSentinelName(%q) = %q, want %q", tc.body, got, tc.want)
+		}
+	}
+}
+
+func TestSetupLogger_JSONFormat(t *testing.T) {
+	// Capture output by creating a logger manually with the same logic
+	var buf bytes.Buffer
+	opts := &slog.HandlerOptions{Level: slog.LevelInfo}
+	handler := slog.NewJSONHandler(&buf, opts)
+	logger := slog.New(handler)
+
+	logger.Info("test message", "key", "value")
+
+	output := buf.String()
+	if !strings.Contains(output, `"msg":"test message"`) {
+		t.Errorf("expected JSON msg field, got: %s", output)
+	}
+	if !strings.Contains(output, `"key":"value"`) {
+		t.Errorf("expected JSON key field, got: %s", output)
+	}
+	if !strings.Contains(output, `"level":"INFO"`) {
+		t.Errorf("expected JSON level field, got: %s", output)
+	}
+}
+
+func TestSetupLogger_TextFormat(t *testing.T) {
+	var buf bytes.Buffer
+	opts := &slog.HandlerOptions{Level: slog.LevelInfo}
+	handler := slog.NewTextHandler(&buf, opts)
+	logger := slog.New(handler)
+
+	logger.Info("test message", "key", "value")
+
+	output := buf.String()
+	if !strings.Contains(output, "msg=\"test message\"") && !strings.Contains(output, "msg=test") {
+		t.Errorf("expected text msg field, got: %s", output)
+	}
+	if !strings.Contains(output, "key=value") {
+		t.Errorf("expected text key field, got: %s", output)
+	}
+}
+
+func TestSetupLogger_LevelFiltering(t *testing.T) {
+	tests := []struct {
+		name      string
+		verbosity string
+		logLevel  slog.Level
+		expected  bool // should the message appear
+	}{
+		{"info logger shows info", "info", slog.LevelInfo, true},
+		{"info logger hides debug", "info", slog.LevelDebug, false},
+		{"debug logger shows debug", "debug", slog.LevelDebug, true},
+		{"warn logger hides info", "warn", slog.LevelInfo, false},
+		{"warn logger shows warn", "warn", slog.LevelWarn, true},
+		{"error logger hides warn", "error", slog.LevelWarn, false},
+		{"error logger shows error", "error", slog.LevelError, true},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			var level slog.Level
+			switch tc.verbosity {
+			case "debug":
+				level = slog.LevelDebug
+			case "info":
+				level = slog.LevelInfo
+			case "warn":
+				level = slog.LevelWarn
+			case "error":
+				level = slog.LevelError
+			}
+
+			var buf bytes.Buffer
+			opts := &slog.HandlerOptions{Level: level}
+			handler := slog.NewTextHandler(&buf, opts)
+			logger := slog.New(handler)
+
+			logger.Log(nil, tc.logLevel, "test")
+
+			hasOutput := buf.Len() > 0
+			if hasOutput != tc.expected {
+				t.Errorf("verbosity=%s, logLevel=%s: got output=%v, want %v",
+					tc.verbosity, tc.logLevel, hasOutput, tc.expected)
+			}
+		})
+	}
+}
+
+func TestSetupLogger_Integration(t *testing.T) {
+	// Test that setupLogger doesn't panic for valid inputs
+	setupLogger("text", "info")
+	setupLogger("json", "debug")
+	setupLogger("text", "warn")
+	setupLogger("json", "error")
+	setupLogger("text", "unknown") // should default to info
+	setupLogger("invalid", "info") // should default to text
+}
+
+func TestIsPatternFile(t *testing.T) {
+	tests := []struct {
+		path string
+		want bool
+	}{
+		{"README.md", true},
+		{"docs/GUIDE.MD", true},
+		{"config.yml", true},
+		{"config.yaml", true},
+		{"notes.txt", true},
+		{"NOTES.TXT", true},
+		{"main.go", false},
+		{"lib.rs", false},
+		{"index.js", false},
+		{"Makefile", false},
+		{"", false},
+		{"doc.pdf", false},
+		{"patterns.Yml", true},
+		{"deep/path/file.yaml", true},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.path, func(t *testing.T) {
+			got := isPatternFile(tc.path)
+			if got != tc.want {
+				t.Errorf("isPatternFile(%q) = %v, want %v", tc.path, got, tc.want)
+			}
+		})
+	}
+}
+
+func TestEvaluateCIStatus(t *testing.T) {
+	tests := []struct {
+		name       string
+		statuses   []vcs.CommitStatus
+		wantPassed bool
+		wantSubstr string
+	}{
+		{
+			name:       "empty statuses",
+			statuses:   nil,
+			wantPassed: true,
+			wantSubstr: "no CI statuses",
+		},
+		{
+			name: "all success",
+			statuses: []vcs.CommitStatus{
+				{Status: "success", Context: "ci/build", Description: "Build passed"},
+				{Status: "success", Context: "ci/test", Description: "Tests passed"},
+			},
+			wantPassed: true,
+			wantSubstr: "all checks passed",
+		},
+		{
+			name: "one failure",
+			statuses: []vcs.CommitStatus{
+				{Status: "success", Context: "ci/build", Description: "Build passed"},
+				{Status: "failure", Context: "ci/test", Description: "Tests failed"},
+			},
+			wantPassed: false,
+			wantSubstr: "ci/test",
+		},
+		{
+			name: "error status",
+			statuses: []vcs.CommitStatus{
+				{Status: "error", Context: "ci/lint", Description: "Lint error"},
+			},
+			wantPassed: false,
+			wantSubstr: "ci/lint",
+		},
+		{
+			name: "pending treated as not-failed",
+			statuses: []vcs.CommitStatus{
+				{Status: "pending", Context: "ci/build", Description: "In progress"},
+				{Status: "success", Context: "ci/test", Description: "Tests passed"},
+			},
+			wantPassed: true,
+			wantSubstr: "no failures",
+		},
+		{
+			name: "multiple failures",
+			statuses: []vcs.CommitStatus{
+				{Status: "failure", Context: "ci/build", Description: "Build failed"},
+				{Status: "failure", Context: "ci/test", Description: "Tests failed"},
+			},
+			wantPassed: false,
+			wantSubstr: "ci/build",
+		},
+		{
+			name: "mixed with pending and failure",
+			statuses: []vcs.CommitStatus{
+				{Status: "success", Context: "ci/build", Description: "Build passed"},
+				{Status: "pending", Context: "ci/deploy", Description: "Deploying"},
+				{Status: "failure", Context: "ci/test", Description: "Tests failed"},
+			},
+			wantPassed: false,
+			wantSubstr: "ci/test",
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			passed, details := evaluateCIStatus(tc.statuses)
+			if passed != tc.wantPassed {
+				t.Errorf("evaluateCIStatus() passed = %v, want %v", passed, tc.wantPassed)
+			}
+			if !strings.Contains(details, tc.wantSubstr) {
+				t.Errorf("evaluateCIStatus() details = %q, want substring %q", details, tc.wantSubstr)
+			}
+		})
+	}
+}
+
+func TestEnvOrDefault(t *testing.T) {
+	// Test with unset env var
+	os.Unsetenv("TEST_ENV_OR_DEFAULT_UNSET")
+	got := envOrDefault("TEST_ENV_OR_DEFAULT_UNSET", "fallback")
+	if got != "fallback" {
+		t.Errorf("envOrDefault(unset) = %q, want %q", got, "fallback")
+	}
+
+	// Test with set env var
+	os.Setenv("TEST_ENV_OR_DEFAULT_SET", "custom")
+	defer os.Unsetenv("TEST_ENV_OR_DEFAULT_SET")
+	got = envOrDefault("TEST_ENV_OR_DEFAULT_SET", "fallback")
+	if got != "custom" {
+		t.Errorf("envOrDefault(set) = %q, want %q", got, "custom")
+	}
+
+	// Test with empty env var (should return default)
+	os.Setenv("TEST_ENV_OR_DEFAULT_EMPTY", "")
+	defer os.Unsetenv("TEST_ENV_OR_DEFAULT_EMPTY")
+	got = envOrDefault("TEST_ENV_OR_DEFAULT_EMPTY", "fallback")
+	if got != "fallback" {
+		t.Errorf("envOrDefault(empty) = %q, want %q", got, "fallback")
+	}
+}
+
+func TestEnvOrDefaultFloat(t *testing.T) {
+	// Test with unset env var
+	os.Unsetenv("TEST_ENV_FLOAT_UNSET")
+	got := envOrDefaultFloat("TEST_ENV_FLOAT_UNSET", 1.5)
+	if got != 1.5 {
+		t.Errorf("envOrDefaultFloat(unset) = %f, want %f", got, 1.5)
+	}
+
+	// Test with valid float
+	os.Setenv("TEST_ENV_FLOAT_SET", "2.7")
+	defer os.Unsetenv("TEST_ENV_FLOAT_SET")
+	got = envOrDefaultFloat("TEST_ENV_FLOAT_SET", 1.5)
+	if got != 2.7 {
+		t.Errorf("envOrDefaultFloat(set) = %f, want %f", got, 2.7)
+	}
+
+	// Test with invalid float (should return default)
+	os.Setenv("TEST_ENV_FLOAT_INVALID", "not-a-number")
+	defer os.Unsetenv("TEST_ENV_FLOAT_INVALID")
+	got = envOrDefaultFloat("TEST_ENV_FLOAT_INVALID", 3.14)
+	if got != 3.14 {
+		t.Errorf("envOrDefaultFloat(invalid) = %f, want %f", got, 3.14)
+	}
+
+	// Test with empty string (should return default)
+	os.Setenv("TEST_ENV_FLOAT_EMPTY", "")
+	defer os.Unsetenv("TEST_ENV_FLOAT_EMPTY")
+	got = envOrDefaultFloat("TEST_ENV_FLOAT_EMPTY", 0.5)
+	if got != 0.5 {
+		t.Errorf("envOrDefaultFloat(empty) = %f, want %f", got, 0.5)
+	}
+}
+
+func TestEnvOrDefaultInt(t *testing.T) {
+	// Test with unset env var
+	os.Unsetenv("TEST_ENV_INT_UNSET")
+	got := envOrDefaultInt("TEST_ENV_INT_UNSET", 42)
+	if got != 42 {
+		t.Errorf("envOrDefaultInt(unset) = %d, want %d", got, 42)
+	}
+
+	// Test with valid int
+	os.Setenv("TEST_ENV_INT_SET", "100")
+	defer os.Unsetenv("TEST_ENV_INT_SET")
+	got = envOrDefaultInt("TEST_ENV_INT_SET", 42)
+	if got != 100 {
+		t.Errorf("envOrDefaultInt(set) = %d, want %d", got, 100)
+	}
+
+	// Test with invalid int (should return default)
+	os.Setenv("TEST_ENV_INT_INVALID", "abc")
+	defer os.Unsetenv("TEST_ENV_INT_INVALID")
+	got = envOrDefaultInt("TEST_ENV_INT_INVALID", 42)
+	if got != 42 {
+		t.Errorf("envOrDefaultInt(invalid) = %d, want %d", got, 42)
+	}
+
+	// Test with empty string (should return default)
+	os.Setenv("TEST_ENV_INT_EMPTY", "")
+	defer os.Unsetenv("TEST_ENV_INT_EMPTY")
+	got = envOrDefaultInt("TEST_ENV_INT_EMPTY", 99)
+	if got != 99 {
+		t.Errorf("envOrDefaultInt(empty) = %d, want %d", got, 99)
+	}
+
+	// Test with negative int
+	os.Setenv("TEST_ENV_INT_NEG", "-5")
+	defer os.Unsetenv("TEST_ENV_INT_NEG")
+	got = envOrDefaultInt("TEST_ENV_INT_NEG", 42)
+	if got != -5 {
+		t.Errorf("envOrDefaultInt(negative) = %d, want %d", got, -5)
+	}
+}
+
+func TestExtractSentinelName_EdgeCases(t *testing.T) {
+	tests := []struct {
+		body string
+		want string
+	}{
+		{"<!-- review-bot:sonnet --> rest", "sonnet"},
+		{"<!-- review-bot:gpt-review --> rest", "gpt-review"},
+		{"no sentinel here", "unknown"},
+		{"<!-- review-bot:", "unknown"},               // prefix but no suffix
+		{"prefix <!-- review-bot:abc --> end", "abc"}, // embedded in text
+	}
+
+	for _, tc := range tests {
+		got := extractSentinelName(tc.body)
+		if got != tc.want {
+			t.Errorf("extractSentinelName(%q) = %q, want %q", tc.body, got, tc.want)
+		}
+	}
+}
+
+// TestMainSubprocess runs main() as a subprocess using the test binary itself.
+// This allows coverage to be captured for main() code paths.
+func TestMainSubprocess_Version(t *testing.T) {
+	if os.Getenv("TEST_SUBPROCESS_MAIN") == "1" {
+		// Reset flags for main()
+		flag.CommandLine = flag.NewFlagSet(os.Args[0], flag.ExitOnError)
+		os.Args = []string{"review-bot", "--version"}
+		main()
+		return
+	}
+
+	cmd := exec.Command(os.Args[0], "-test.run=TestMainSubprocess_Version")
+	cmd.Env = append(os.Environ(), "TEST_SUBPROCESS_MAIN=1")
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		t.Fatalf("--version subprocess failed: %v\n%s", err, out)
+	}
+	if !strings.Contains(string(out), "review-bot") {
+		t.Errorf("--version output = %q, want to contain 'review-bot'", string(out))
+	}
+}
+
+func TestMainSubprocess_MissingFlags(t *testing.T) {
+	if os.Getenv("TEST_SUBPROCESS_MAIN") == "1" {
+		// Reset flags for main()
+		flag.CommandLine = flag.NewFlagSet(os.Args[0], flag.ExitOnError)
+		os.Args = []string{"review-bot"}
+		main()
+		return
+	}
+
+	cmd := exec.Command(os.Args[0], "-test.run=TestMainSubprocess_MissingFlags")
+	cmd.Env = append(cleanEnv(), "TEST_SUBPROCESS_MAIN=1")
+	out, err := cmd.CombinedOutput()
+	if err == nil {
+		t.Fatal("expected non-zero exit with no flags, got success")
+	}
+	if !strings.Contains(string(out), "missing required") {
+		t.Errorf("expected error about missing flags, got: %s", out)
+	}
+}
+
+func TestMainSubprocess_InvalidReviewerName(t *testing.T) {
+	if os.Getenv("TEST_SUBPROCESS_MAIN") == "1" {
+		flag.CommandLine = flag.NewFlagSet(os.Args[0], flag.ExitOnError)
+		os.Args = []string{"review-bot",
+			"--vcs-url", "http://localhost",
+			"--repo", "owner/repo",
+			"--pr", "1",
+			"--reviewer-name", "invalid name",
+			"--reviewer-token", "tok",
+			"--llm-base-url", "http://localhost",
+			"--llm-api-key", "key",
+			"--llm-model", "model",
+		}
+		main()
+		return
+	}
+
+	cmd := exec.Command(os.Args[0], "-test.run=TestMainSubprocess_InvalidReviewerName")
+	cmd.Env = append(cleanEnv(), "TEST_SUBPROCESS_MAIN=1")
+	out, err := cmd.CombinedOutput()
+	if err == nil {
+		t.Fatal("expected non-zero exit with invalid reviewer-name, got success")
+	}
+	if !strings.Contains(string(out), "invalid reviewer name") {
+		t.Errorf("expected error about invalid reviewer name, got: %s", out)
+	}
+}
+
+func TestMainSubprocess_InvalidRepo(t *testing.T) {
+	if os.Getenv("TEST_SUBPROCESS_MAIN") == "1" {
+		flag.CommandLine = flag.NewFlagSet(os.Args[0], flag.ExitOnError)
+		os.Args = []string{"review-bot",
+			"--vcs-url", "http://localhost",
+			"--repo", "invalidrepo",
+			"--pr", "1",
+			"--reviewer-token", "tok",
+			"--llm-base-url", "http://localhost",
+			"--llm-api-key", "key",
+			"--llm-model", "model",
+		}
+		main()
+		return
+	}
+
+	cmd := exec.Command(os.Args[0], "-test.run=TestMainSubprocess_InvalidRepo")
+	cmd.Env = append(cleanEnv(), "TEST_SUBPROCESS_MAIN=1")
+	out, err := cmd.CombinedOutput()
+	if err == nil {
+		t.Fatal("expected non-zero exit with invalid repo format")
+	}
+	if !strings.Contains(string(out), "invalid repo format") {
+		t.Errorf("expected error about invalid repo, got: %s", out)
+	}
+}
+
+func TestMainSubprocess_InvalidPRNumber(t *testing.T) {
+	if os.Getenv("TEST_SUBPROCESS_MAIN") == "1" {
+		flag.CommandLine = flag.NewFlagSet(os.Args[0], flag.ExitOnError)
+		os.Args = []string{"review-bot",
+			"--vcs-url", "http://localhost",
+			"--repo", "owner/repo",
+			"--pr", "notanumber",
+			"--reviewer-token", "tok",
+			"--llm-base-url", "http://localhost",
+			"--llm-api-key", "key",
+			"--llm-model", "model",
+		}
+		main()
+		return
+	}
+
+	cmd := exec.Command(os.Args[0], "-test.run=TestMainSubprocess_InvalidPRNumber")
+	cmd.Env = append(cleanEnv(), "TEST_SUBPROCESS_MAIN=1")
+	out, err := cmd.CombinedOutput()
+	if err == nil {
+		t.Fatal("expected non-zero exit with invalid PR number")
+	}
+	if !strings.Contains(string(out), "invalid PR number") {
+		t.Errorf("expected error about invalid PR number, got: %s", out)
+	}
+}
+
+func TestMainSubprocess_InvalidTemperature(t *testing.T) {
+	if os.Getenv("TEST_SUBPROCESS_MAIN") == "1" {
+		flag.CommandLine = flag.NewFlagSet(os.Args[0], flag.ExitOnError)
+		os.Args = []string{"review-bot",
+			"--vcs-url", "http://localhost",
+			"--repo", "owner/repo",
+			"--pr", "1",
+			"--reviewer-token", "tok",
+			"--llm-base-url", "http://localhost",
+			"--llm-api-key", "key",
+			"--llm-model", "model",
+			"--llm-temperature", "5.0",
+		}
+		main()
+		return
+	}
+
+	cmd := exec.Command(os.Args[0], "-test.run=TestMainSubprocess_InvalidTemperature")
+	cmd.Env = append(cleanEnv(), "TEST_SUBPROCESS_MAIN=1")
+	out, err := cmd.CombinedOutput()
+	if err == nil {
+		t.Fatal("expected non-zero exit with invalid temperature")
+	}
+	if !strings.Contains(string(out), "invalid LLM temperature") {
+		t.Errorf("expected error about invalid temperature, got: %s", out)
+	}
+}
+
+func TestMainSubprocess_InvalidProvider(t *testing.T) {
+	if os.Getenv("TEST_SUBPROCESS_MAIN") == "1" {
+		flag.CommandLine = flag.NewFlagSet(os.Args[0], flag.ExitOnError)
+		os.Args = []string{"review-bot",
+			"--vcs-url", "http://localhost",
+			"--repo", "owner/repo",
+			"--pr", "1",
+			"--reviewer-token", "tok",
+			"--llm-base-url", "http://localhost",
+			"--llm-api-key", "key",
+			"--llm-model", "model",
+			"--llm-provider", "invalid-provider",
+		}
+		main()
+		return
+	}
+
+	cmd := exec.Command(os.Args[0], "-test.run=TestMainSubprocess_InvalidProvider")
+	cmd.Env = append(cleanEnv(), "TEST_SUBPROCESS_MAIN=1")
+	out, err := cmd.CombinedOutput()
+	if err == nil {
+		t.Fatal("expected non-zero exit with invalid provider")
+	}
+	if !strings.Contains(string(out), "invalid LLM provider") {
+		t.Errorf("expected error about invalid provider, got: %s", out)
+	}
+}
+
+func TestMainSubprocess_InvalidVCSProvider(t *testing.T) {
+	if os.Getenv("TEST_SUBPROCESS_MAIN") == "1" {
+		flag.CommandLine = flag.NewFlagSet(os.Args[0], flag.ExitOnError)
+		os.Args = []string{"review-bot",
+			"--provider", "invalid",
+			"--vcs-url", "http://localhost",
+			"--repo", "owner/repo",
+			"--pr", "1",
+			"--reviewer-token", "tok",
+			"--llm-base-url", "http://localhost",
+			"--llm-api-key", "key",
+			"--llm-model", "model",
+		}
+		main()
+		return
+	}
+
+	cmd := exec.Command(os.Args[0], "-test.run=TestMainSubprocess_InvalidVCSProvider")
+	cmd.Env = append(cleanEnv(), "TEST_SUBPROCESS_MAIN=1")
+	out, err := cmd.CombinedOutput()
+	if err == nil {
+		t.Fatal("expected non-zero exit with invalid VCS provider")
+	}
+	if !strings.Contains(string(out), "invalid --provider") {
+		t.Errorf("expected error about invalid --provider, got: %s", out)
+	}
+}
+
+// cleanEnv returns environ without any GITEA/LLM/REVIEWER/VCS env vars that would
+// interfere with testing missing-flag scenarios.
+func cleanEnv() []string {
+	var env []string
+	for _, e := range os.Environ() {
+		key := strings.SplitN(e, "=", 2)[0]
+		switch {
+		case strings.HasPrefix(key, "GITEA_"),
+			strings.HasPrefix(key, "VCS_"),
+			strings.HasPrefix(key, "LLM_"),
+			strings.HasPrefix(key, "REVIEWER_"),
+			strings.HasPrefix(key, "PR_"),
+			strings.HasPrefix(key, "LOG_"),
+			strings.HasPrefix(key, "CONVENTIONS_"),
+			strings.HasPrefix(key, "SYSTEM_PROMPT_"),
+			strings.HasPrefix(key, "PATTERNS_"),
+			strings.HasPrefix(key, "UPDATE_"):
+			continue
+		default:
+			env = append(env, e)
+		}
+	}
+	return env
+}
+
+func TestFindAllOwnReviews(t *testing.T) {
+	reviews := []vcs.Review{
+		makeReview(1, "bot", "APPROVED", false, "<!-- review-bot:sonnet -->\nfirst review"),
+		makeReview(2, "bot", "APPROVED", false, "<!-- review-bot:gpt -->\nother bot"),
+		makeReview(3, "bot", "APPROVED", false, "<!-- review-bot:sonnet -->\nsecond review"),
+		makeReview(4, "bot", "APPROVED", false, "~~Original review~~\n<!-- review-bot:sonnet -->\nsuperseded"),
+		makeReview(5, "bot", "APPROVED", false, "<!-- review-bot:sonnet -->\nthird review"),
+	}
+
+	got := findAllOwnReviews(reviews, "<!-- review-bot:sonnet -->")
+	if len(got) != 3 {
+		t.Fatalf("findAllOwnReviews() returned %d, want 3", len(got))
+	}
+	wantIDs := []int64{1, 3, 5}
+	for i, r := range got {
+		if r.ID != wantIDs[i] {
+			t.Errorf("got[%d].ID = %d, want %d", i, r.ID, wantIDs[i])
+		}
+	}
+}
+
+func TestShouldSkipStaleReview(t *testing.T) {
+	tests := []struct {
+		name         string
+		evaluatedSHA string
+		currentSHA   string
+		wantSkip     bool
+	}{
+		{
+			name:         "matching SHAs",
+			evaluatedSHA: "abc123def456",
+			currentSHA:   "abc123def456",
+			wantSkip:     false,
+		},
+		{
+			name:         "different SHAs",
+			evaluatedSHA: "abc123def456",
+			currentSHA:   "xyz789abc123",
+			wantSkip:     true,
+		},
+		{
+			name:         "empty current SHA (re-fetch failed)",
+			evaluatedSHA: "abc123def456",
+			currentSHA:   "",
+			wantSkip:     false,
+		},
+		{
+			name:         "both empty (edge case)",
+			evaluatedSHA: "",
+			currentSHA:   "",
+			wantSkip:     false,
+		},
+		{
+			name:         "only current empty",
+			evaluatedSHA: "abc123",
+			currentSHA:   "",
+			wantSkip:     false,
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			got := shouldSkipStaleReview(tc.evaluatedSHA, tc.currentSHA)
+			if got != tc.wantSkip {
+				t.Errorf("shouldSkipStaleReview(%q, %q) = %v, want %v",
+					tc.evaluatedSHA, tc.currentSHA, got, tc.wantSkip)
+			}
+		})
+	}
+}
+
+func TestVerdictToEvent(t *testing.T) {
+	tests := []struct {
+		verdict string
+		want    vcs.ReviewEvent
+	}{
+		{"APPROVE", vcs.ReviewEventApprove},
+		{"REQUEST_CHANGES", vcs.ReviewEventRequestChanges},
+		{"COMMENT", vcs.ReviewEventComment},
+		{"other", vcs.ReviewEventComment},
+		{"", vcs.ReviewEventComment},
+	}
+
+	for _, tc := range tests {
+		got := verdictToEvent(tc.verdict)
+		if got != tc.want {
+			t.Errorf("verdictToEvent(%q) = %q, want %q", tc.verdict, got, tc.want)
+		}
+	}
+}

docs/DESIGN-51-personas.md

@@ -0,0 +1,334 @@
+# Design: Role-based Review Personas (Issue #51)
+
+> **Note:** This design was revised during implementation to use JSON instead of YAML
+> to maintain the repository's zero-external-dependencies convention. All persona
+> files use JSON format. See "Design Revision" section at the end for details.
+
+## Problem
+
+Current review-bot performs generic code review. Every reviewer (regardless of `reviewer-name`) uses the same base prompt and evaluates the same concerns. This leads to:
+
+1. **Redundancy** — Two reviewers (e.g., GPT + Claude twins) often flag identical issues
+2. **Gaps** — Generic reviewers miss specialized concerns (security, domain logic, architecture)
+3. **Noise** — NITs about style mixed with critical security findings
+4. **No ownership** — Findings lack clear domain attribution
+
+## Constraints
+
+- Must work with existing CLI flags and CI workflow patterns
+- Must not break backwards compatibility (existing configs still work)
+- Must integrate cleanly with the budget system (personas add to context)
+- Multiple personas running in parallel must not interfere with each other
+- Each persona must have clear scope boundaries (no duplication)
+
+## Proposed Approach
+
+### 1. Persona Definition
+
+A persona is a named review role with:
+- **Identity** — Who am I? What's my expertise?
+- **Focus** — What do I look for?
+- **Scope boundaries** — What do I explicitly NOT comment on?
+- **Severity calibration** — What counts as MAJOR/MINOR/NIT for MY domain?
+
+Personas are defined in JSON files that can live:
+1. In the pattern repos (shared across projects)
+2. In the target repo (project-specific personas)
+3. Inline via a new `--persona-file` flag (JSON format)
+
+### 2. Persona File Format
+
+```json
+# .review/personas/security.yaml
+name: security
+display_name: Security Specialist
+model_preference: opus  # optional hint for expensive analysis
+
+identity: |
+  You are a security specialist reviewing code for vulnerabilities.
+  Your expertise: OWASP Top 10, injection attacks, auth/authz, secrets management,
+  event sourcing security (replay attacks, event injection).
+
+focus:
+  - Injection attacks (SQL, command, path traversal, template)
+  - Authentication and authorization gaps
+  - Secrets exposure (hardcoded credentials, tokens in logs)
+  - Input validation (unsanitized input, unsafe deserialization)
+  - Race conditions with security implications
+  - Event sourcing attack vectors
+
+ignore:
+  - Code style and naming conventions
+  - Performance (unless security-related)
+  - Documentation
+  - General code quality
+  - Test coverage
+
+severity:
+  critical: "Remote code execution, auth bypass, data exfiltration"
+  major: "Privilege escalation, information disclosure, DoS"
+  minor: "Missing rate limiting, verbose errors"
+  nit: "Theoretical risk with low exploitability"
+
+output_format: |
+  For each finding:
+  - Severity: [CRITICAL|MAJOR|MINOR|NIT]
+  - Attack vector: How could this be exploited?
+  - Evidence: Code snippet showing the vulnerability
+  - Recommendation: Specific fix
+```
+
+### 3. New CLI Flags
+
+```
+--persona-file PATH      Path to persona JSON file (local or in repo)
+--persona NAME           Built-in persona name (security, architect, domain)
+```
+
+Either flag sets the persona. If neither is provided, behavior is unchanged (generic review).
+
+### 4. Prompt Assembly
+
+Current flow:
+```
+SystemBase → Patterns → Conventions → [LLM]
+```
+
+New flow with persona:
+```
+PersonaPrompt (from YAML) → Patterns (filtered?) → Conventions → [LLM]
+```
+
+The persona's identity/focus/ignore/severity sections become the system prompt, replacing the generic "You are an expert code reviewer" base.
+
+### 5. Built-in Personas
+
+Ship with these built-in personas (loadable via `--persona NAME`):
+
+| Name | Focus |
+|------|-------|
+| `security` | Vulnerabilities, auth, secrets |
+| `architect` | Patterns, consistency, design |
+| `domain` | Business logic (requires repo-specific config) |
+| `docs` | Documentation, API clarity |
+
+Built-in personas live in `review/personas/` as embedded Go assets or YAML shipped with the binary.
+
+### 6. CI Workflow Integration
+
+Single persona:
+```yaml
+- uses: rodin/review-bot/.gitea/actions/review@v1
+  with:
+    reviewer-name: security
+    persona: security
+    ...
+```
+
+Multiple personas (parallel jobs):
+```yaml
+jobs:
+  review:
+    strategy:
+      matrix:
+        include:
+          - name: security
+            persona: security
+          - name: architect
+            persona: architect
+    steps:
+      - uses: rodin/review-bot/.gitea/actions/review@v1
+        with:
+          reviewer-name: ${{ matrix.name }}
+          persona: ${{ matrix.persona }}
+```
+
+Custom persona from repo:
+```yaml
+- uses: rodin/review-bot/.gitea/actions/review@v1
+  with:
+    reviewer-name: trading
+    persona-file: .review/personas/trading.yaml
+```
+
+### 7. Persona + Patterns Interaction
+
+Some personas benefit from filtered patterns:
+- Security → only security-related patterns
+- Architect → all patterns (structural focus)
+- Domain → domain docs, not language patterns
+
+For v1, keep it simple: all patterns are included regardless of persona. Future enhancement could add `patterns_filter` to persona YAML.
+
+### 8. Output Format Changes
+
+Persona name appears in the review header:
+```markdown
+# Security Review
+
+## Summary
+No critical vulnerabilities found in this change.
+
+## Findings
+| # | Severity | File | Line | Finding |
+...
+
+## Recommendation
+**APPROVE** — No security-relevant issues detected.
+
+---
+*Review by security*
+<!-- review-bot:security -->
+```
+
+## State/Data Model
+
+### Persona struct
+
+```go
+// review/persona.go
+type Persona struct {
+    Name          string   `yaml:"name"`
+    DisplayName   string   `yaml:"display_name"`
+    ModelPref     string   `yaml:"model_preference,omitempty"`
+    Identity      string   `yaml:"identity"`
+    Focus         []string `yaml:"focus"`
+    Ignore        []string `yaml:"ignore"`
+    Severity      Severity `yaml:"severity"`
+    OutputFormat  string   `yaml:"output_format,omitempty"`
+}
+
+type Severity struct {
+    Critical string `yaml:"critical"`
+    Major    string `yaml:"major"`
+    Minor    string `yaml:"minor"`
+    Nit      string `yaml:"nit"`
+}
+```
+
+### Loading precedence
+
+1. `--persona-file PATH` → load from local file system
+2. `--persona NAME` → load from embedded built-ins
+3. Neither → use generic system prompt (current behavior)
+
+## Error Cases
+
+| Error | Handling |
+|-------|----------|
+| Persona file not found | Fatal exit with clear message |
+| Invalid YAML in persona file | Fatal exit with parse error |
+| Both `--persona` and `--persona-file` specified | Fatal exit: mutually exclusive |
+| Unknown built-in persona name | Fatal exit with list of valid names |
+| Empty identity in persona | Warning, fall back to generic prompt |
+
+## Edge Cases
+
+- **Empty focus list**: Valid — persona relies on identity alone
+- **Empty ignore list**: Valid — no explicit scope exclusions
+- **No severity section**: Use default MAJOR/MINOR/NIT definitions
+- **Model preference set but budget insufficient**: Ignore preference, log warning
+- **Persona file in pattern repo**: Fetch like other pattern files
+
+## Testing Strategy
+
+### Unit tests
+- `persona_test.go`: Parse valid/invalid YAML, validate required fields
+- `prompt_test.go`: Verify persona prompt assembly
+- Integration with budget: persona prompts count toward token limit
+
+### Integration tests
+- End-to-end with `--persona security` (built-in)
+- End-to-end with `--persona-file custom.yaml`
+- Backwards compatibility: no flags = generic behavior
+
+### Manual verification
+- Run security persona on a PR with obvious vulnerability
+- Verify security persona ignores style issues
+- Verify non-security persona doesn't flag security issues
+
+## Implementation Phases
+
+### Phase 1: Persona types and loading
+- [ ] `review/persona.go`: Persona struct + YAML parsing
+- [ ] `review/persona_test.go`: Unit tests
+- [ ] Embed built-in personas in binary
+- [ ] Compiles clean, tests pass
+
+### Phase 2: Prompt generation
+- [ ] `review/prompt.go`: `BuildPersonaPrompt(p Persona) string`
+- [ ] Modify `BuildSystemBase()` to accept optional persona
+- [ ] Integrate persona prompt with budget system
+- [ ] Tests for prompt assembly
+
+### Phase 3: CLI integration
+- [ ] Add `--persona` and `--persona-file` flags
+- [ ] Flag validation (mutually exclusive, valid names)
+- [ ] Load persona based on flags
+- [ ] Pass persona to prompt builder
+
+### Phase 4: Action integration
+- [ ] Add `persona` and `persona-file` inputs to action.yml
+- [ ] Update README with persona examples
+- [ ] End-to-end CI test
+
+### Phase 5: Built-in personas
+- [ ] `security.yaml` built-in
+- [ ] `architect.yaml` built-in
+- [ ] `docs.yaml` built-in
+- [ ] Document each persona's focus
+
+## Open Questions
+
+1. **Persona file location in repo**: Should we support `--persona-file .review/security.yaml` where the file is fetched from the PR's repo (like conventions)? This adds complexity but enables project-specific personas without action changes.
+
+2. **Model preference enforcement**: If persona specifies `model_preference: opus` but the action uses a different model, should we warn? Override? Ignore? Current thinking: log warning, use the specified model (user controls model via action input).
+
+3. **Severity override output**: If persona defines custom severity levels (CRITICAL), should the JSON output include them, or map back to standard MAJOR/MINOR/NIT? Current thinking: keep standard output format, use severity calibration only for prompt guidance.
+
+## Completion Checklist
+
+1. Persona struct matches YAML schema exactly?
+2. Built-in personas embedded in binary (not external files)?
+3. `--persona` and `--persona-file` are mutually exclusive?
+4. Unknown persona name produces clear error with valid options?
+5. Empty persona file fields have sensible defaults?
+6. Persona prompt integrates with budget system (token counting)?
+7. Backwards compatibility: no flags = current behavior?
+8. Review header shows persona display name?
+9. Sentinel still uses reviewer-name (not persona name)?
+10. Unit tests cover parse errors, missing fields, valid YAML?
+
+## Design Review Findings (Self-Review)
+
+### Finding 1: Severity Mapping
+The persona YAML allows `critical` severity, but the LLM output parser (`review/parser.go`) only accepts MAJOR/MINOR/NIT. 
+
+**Resolution:** Keep standard output format. Persona severity section is ONLY for calibrating the LLM's judgment (prompt guidance). Output must still use MAJOR/MINOR/NIT. Document this clearly in persona format docs.
+
+### Finding 2: Embedding Built-in Personas
+Go doesn't natively embed YAML. Must use `//go:embed` directive (Go 1.16+).
+
+**Resolution:** Create `review/personas/` directory with YAML files and use:
+```go
+//go:embed personas/*.yaml
+var embeddedPersonas embed.FS
+```
+
+### Finding 3: display_name vs reviewer-name
+Design says header shows "persona display name" but sentinel uses "reviewer-name". This is correct - they serve different purposes:
+- `display_name` → human-readable header ("Security Specialist Review")
+- `reviewer-name` → machine sentinel for cleanup (`<!-- review-bot:security -->`)
+
+When persona is used, `display_name` takes precedence for the header title, but `reviewer-name` (CLI flag) is still used for the sentinel.
+
+## Design Revision: YAML with gopkg.in/yaml.v3
+
+**Decision:** Add `gopkg.in/yaml.v3` as a dependency.
+
+YAML is preferred over JSON for persona files because:
+- Multi-line strings are cleaner (no escaping quotes in identity/focus text)
+- Comments are supported for documentation
+- More human-readable for complex persona definitions
+
+The implementation supports both YAML (`.yaml`, `.yml`) and JSON (`.json`) for backwards compatibility, with YAML as the default for built-in personas.

docs/DESIGN-57-yaml-persona.md

@@ -0,0 +1,108 @@
+# Design: YAML Support for Persona Files (#57)
+
+## Problem
+
+JSON is awkward for persona files that contain multi-line text (identity, severity descriptions). YAML supports cleaner multi-line strings and comments, improving readability and maintainability.
+
+## Constraints
+
+- Backwards compatibility: existing JSON personas must continue to work
+- Security: protect against DoS via deeply nested YAML (AIKIDO-2024-10486)
+- Consistency: use `.yaml` extension (not `.yml`)
+- Library: use `gopkg.in/yaml.v3` (approved in CONVENTIONS.md) with explicit depth limiting
+
+## Proposed Approach
+
+1. **Update `parsePersona`** to detect format from file extension
+2. **Add YAML parsing** with explicit depth limit (defense in depth)
+3. **Keep JSON as fallback** for files without `.yaml`/`.yml` extension
+4. **Convert built-in personas** to YAML format
+5. **Update embed directive** to include both formats
+
+### File Extension Detection
+
+```go
+func parsePersona(data []byte, source string) (*Persona, error) {
+    isYAML := strings.HasSuffix(source, ".yaml") || strings.HasSuffix(source, ".yml")
+    if isYAML {
+        return parseYAML(data, source)
+    }
+    return parseJSON(data, source)
+}
+```
+
+### YAML Parsing with Depth Protection
+
+```go
+func unmarshalYAMLWithDepthLimit(data []byte, out any, maxDepth int) error {
+    var node yaml.Node
+    dec := yaml.NewDecoder(bytes.NewReader(data))
+    if err := dec.Decode(&node); err != nil {
+        return err
+    }
+    if err := checkYAMLDepth(&node, 0, maxDepth); err != nil {
+        return err
+    }
+    return node.Decode(out)
+}
+
+func checkYAMLDepth(node *yaml.Node, depth, maxDepth int) error {
+    if depth > maxDepth {
+        return fmt.Errorf("YAML nesting depth exceeds maximum (%d)", maxDepth)
+    }
+    // Handle alias nodes by following the Alias pointer
+    if node.Kind == yaml.AliasNode && node.Alias != nil {
+        return checkYAMLDepth(node.Alias, depth, maxDepth)
+    }
+    for _, child := range node.Content {
+        if err := checkYAMLDepth(child, depth+1, maxDepth); err != nil {
+            return err
+        }
+    }
+    return nil
+}
+```
+
+The `gopkg.in/yaml.v3` library does not have built-in depth protection, so we implement explicit depth checking by first decoding into a `yaml.Node`, walking the tree to verify depth (including alias resolution), then decoding into the target struct.
+
+## State/Data Model
+
+No new state. Same `Persona` struct, just different parsing.
+
+## Error Cases
+
+| Error | Handling |
+|-------|----------|
+| Invalid YAML syntax | Return parse error with source file |
+| Deeply nested YAML | Library rejects (v1.16.0+ fix) |
+| Unknown extension | Fall back to JSON parsing |
+| Missing required fields | Validation rejects after parse |
+
+## Edge Cases
+
+- File with `.json` extension but YAML content → JSON parse fails, user sees error
+- File with no extension → defaults to JSON
+- Embedded persona reference like `builtin:security` → detect by embed path (`personas/X.yaml`)
+
+## Testing Strategy
+
+1. Unit tests for YAML parsing (valid, invalid, deeply nested)
+2. Unit tests for extension detection
+3. Integration test for built-in personas (now YAML)
+4. Backwards compat test: verify JSON still works for external files
+
+## Completion Checklist
+
+1. [ ] `go-yaml` dependency added at v1.16.0+
+2. [ ] Extension detection uses case-insensitive comparison
+3. [ ] YAML parse errors include source file name
+4. [ ] JSON parsing still works for `.json` files
+5. [ ] Built-in personas converted to YAML with readable multi-line strings
+6. [ ] Embed directive updated to include `*.yaml`
+7. [ ] Test for deeply nested YAML rejection
+8. [ ] All existing tests pass
+
+## Open Questions
+
+- Should we support both `.yaml` AND `.yml`? Issue says `.yaml` only for consistency, but some users expect `.yml`. **Decision:** Support both for reading, recommend `.yaml` in docs.
+- Should we add a "format" field to detect mismatched extension/content? **Decision:** No, keep it simple. Extension determines format.

docs/DESIGN-vcs-abstraction.md

@@ -0,0 +1,268 @@
+# GitHub Support for review-bot
+
+## Goal
+
+AI code reviews on GitHub PRs using SAP AI Core as the LLM provider.
+
+## Non-Goals
+
+- Auto-detection of platform (explicit `--provider` flag is fine)
+- Unifying into one abstraction layer for its own sake
+
+## Constraints
+
+1. **Same features on both platforms** — anything review-bot does on Gitea should work on GitHub
+2. **Testable** — small interfaces, dependency injection, no global state
+3. **Interface from working code** — extract from gitea/, don't invent in vacuum
+
+---
+
+## Part 1: Feature Inventory
+
+What does review-bot actually do?
+
+### Core Review Flow
+
+| Feature | Description |
+|---------|-------------|
+| Get PR metadata | Title, body, head SHA, base ref |
+| Get PR diff | Unified diff format |
+| Get PR files | List of changed files with status |
+| Get file content | Raw file at ref |
+| List directory | Enumerate files in path |
+| Post review | Body + inline comments + verdict |
+
+### Review Management
+
+| Feature | Description |
+|---------|-------------|
+| List reviews | Get existing reviews on PR |
+| Delete review | Remove old review before re-posting |
+| Get authenticated user | Who am I? |
+
+### Platform-Specific (not in shared interface)
+
+| Feature | Gitea | GitHub |
+|---------|-------|--------|
+| Resolve comment | Yes | No equivalent |
+| Timeline API | Yes | No equivalent |
+
+These stay on gitea.Client directly. Callers that need them type-assert.
+
+---
+
+## Part 2: GitHub API Mapping
+
+| Feature | Gitea API | GitHub API |
+|---------|-----------|------------|
+| Get PR | `GET /api/v1/repos/.../pulls/{n}` | `GET /repos/.../pulls/{n}` |
+| Get diff | `.diff` suffix | `Accept: application/vnd.github.diff` header |
+| Get files | `GET .../pulls/{n}/files` | Same |
+| Get file content | `GET .../raw/{path}?ref=` | `GET .../contents/{path}?ref=` + base64 decode |
+| List directory | `GET .../contents/{path}` | Same |
+| Post review | `POST .../pulls/{n}/reviews` | Same (adapter handles comment schema) |
+| List reviews | `GET .../pulls/{n}/reviews` | Same |
+| Delete review | `DELETE .../pulls/{n}/reviews/{id}` | Same |
+| Get user | `GET /api/v1/user` | `GET /user` |
+
+---
+
+## Part 3: Interface Design
+
+**Principle:** Extract from working gitea/ code. The interface is discovered, not invented.
+
+### Small, role-based interfaces
+
+```go
+// vcs/interfaces.go
+
+type PRReader interface {
+    GetPullRequest(ctx context.Context, owner, repo string, number int) (*PullRequest, error)
+    GetPullRequestDiff(ctx context.Context, owner, repo string, number int) (string, error)
+    GetPullRequestFiles(ctx context.Context, owner, repo string, number int) ([]ChangedFile, error)
+}
+
+type FileReader interface {
+    GetFileContent(ctx context.Context, owner, repo, path, ref string) (string, error)
+    ListContents(ctx context.Context, owner, repo, path string) ([]ContentEntry, error)
+}
+
+type Reviewer interface {
+    PostReview(ctx context.Context, owner, repo string, number int, req ReviewRequest) (*Review, error)
+    ListReviews(ctx context.Context, owner, repo string, number int) ([]Review, error)
+    DeleteReview(ctx context.Context, owner, repo string, number int, reviewID int64) error
+}
+
+type Identity interface {
+    GetAuthenticatedUser(ctx context.Context) (string, error)
+}
+
+// Client combines all for callers that need everything
+type Client interface {
+    PRReader
+    FileReader
+    Reviewer
+    Identity
+}
+```
+
+### Types
+
+Use what gitea/ already has. Move to vcs/types.go or re-export.
+
+```go
+type PullRequest struct { ... }   // from gitea.PullRequest
+type ChangedFile struct { ... }   // from gitea.ChangedFile
+type ContentEntry struct { ... }  // from gitea.ContentEntry
+type Review struct { ... }        // from gitea.Review
+type ReviewRequest struct { ... } // new, for PostReview input
+type ReviewComment struct { ... } // from gitea.ReviewComment
+```
+
+### Adapter responsibilities
+
+Each adapter (gitea, github) handles:
+- API URL construction
+- Auth header format (`token` vs `Bearer`)
+- Request/response mapping
+- Comment schema translation (line numbers, commit IDs, etc.)
+
+---
+
+## Part 4: Test Plan
+
+### Unit Tests (mock HTTP)
+
+```
+github/
+  pr_test.go        # TestGetPullRequest, TestGetDiff, TestGetFiles
+  files_test.go     # TestGetFileContent, TestListContents
+  review_test.go    # TestPostReview, TestListReviews, TestDeleteReview
+  identity_test.go  # TestGetAuthenticatedUser
+```
+
+Per method: happy path, 404, 401, 429, malformed response.
+
+### Integration Tests
+
+Against github.com/aweiker/ai-core-review-bot:
+- Fetch real PR
+- Fetch real file
+- Post + delete review (clean up)
+
+### End-to-End
+
+Open PR on test repo, run full review-bot, verify review appears.
+
+---
+
+## Part 5: Implementation Phases
+
+### Phase 1: Extract interfaces from gitea/
+
+**Work:**
+- Create `vcs/interfaces.go` with interfaces extracted from gitea/client.go signatures
+- Create `vcs/types.go` — move or alias types from gitea/
+- Verify gitea.Client satisfies vcs.Client (compile-time check)
+
+**Exit criteria:** `var _ vcs.Client = (*gitea.Client)(nil)` compiles.
+
+---
+
+### Phase 2: Gitea adapter (if needed)
+
+**Work:**
+- If gitea.Client method signatures don't match exactly, create wrapper
+- Keep gitea/ working exactly as before
+
+**Exit criteria:** Existing tests pass. No behavior change.
+
+---
+
+### Phase 3: GitHub client — PRReader
+
+**Work:**
+- `github/client.go` — struct, constructor, HTTP helpers
+- `github/pr.go` — GetPullRequest, GetPullRequestDiff, GetPullRequestFiles
+- Unit tests
+
+**Exit criteria:** `go test ./github/...` passes for PR methods.
+
+---
+
+### Phase 4: GitHub client — FileReader
+
+**Work:**
+- `github/files.go` — GetFileContent, ListContents
+- Unit tests
+
+**Exit criteria:** Unit tests pass.
+
+---
+
+### Phase 5: GitHub client — Reviewer + Identity
+
+**Work:**
+- `github/review.go` — PostReview, ListReviews, DeleteReview
+- `github/identity.go` — GetAuthenticatedUser
+- Unit tests
+
+**Exit criteria:** Unit tests pass.
+
+---
+
+### Phase 6: Integration tests
+
+**Work:**
+- `integration/github_test.go`
+- Test against real GitHub
+
+**Exit criteria:** All integration tests pass.
+
+---
+
+### Phase 7: Wire into cmd/review-bot
+
+**Work:**
+- Add `--provider github|gitea` flag (default: gitea for backward compat)
+- Select client based on flag
+- Update to use vcs interfaces where it makes sense
+
+**Exit criteria:**
+- `./review-bot --provider github ...` works
+- `./review-bot --provider gitea ...` works (same as before)
+- Existing Gitea workflows unchanged
+
+---
+
+### Phase 8: GitHub Actions workflow + releases
+
+**Work:**
+- `.github/workflows/ci.yml` — test on PR
+- `.github/workflows/release.yml` — publish binary to GitHub releases
+- `.github/actions/review/action.yml` — composite action
+- Action downloads binary from github.com/aweiker/ai-core-review-bot releases
+
+**Exit criteria:** 
+- CI runs on github.com/aweiker/ai-core-review-bot
+- Release creates downloadable binary
+- Review action posts review successfully
+
+---
+
+## Part 6: Decisions
+
+| Question | Decision |
+|----------|----------|
+| Auth token | Workflow `GITHUB_TOKEN` (automatic) |
+| Binary distribution | GitHub releases on aweiker/ai-core-review-bot |
+| Comment schema | Adapter's job — translate ReviewComment to platform format |
+| Default provider | `gitea` for backward compatibility |
+| Shared types | vcs/types.go (extracted from gitea/) |
+| Platform-specific features | Stay on concrete client, not interface |
+
+---
+
+## Summary
+
+8 phases. Start by extracting interfaces from working gitea/ code, not inventing them. GitHub implements the same interfaces. Each phase has clear exit criteria.

docs/REVIEW_STRATEGY.md

@@ -0,0 +1,97 @@
+# Review Update Strategy
+
+review-bot uses an **edit-in-place** strategy for updating reviews. Reviews are never deleted — this preserves conversation threads on inline comments.
+
+## State Transition Diagram
+
+```mermaid
+stateDiagram-v2
+    [*] --> NoExistingReview: First run
+
+    NoExistingReview --> POST_Review: Generate findings + event
+    POST_Review --> PostEscalationCheck: event == APPROVED?
+
+    PostEscalationCheck --> Done: No sibling blocks
+    PostEscalationCheck --> Supersede_And_Repost: Sibling has REQUEST_CHANGES
+    Supersede_And_Repost --> Done: Posted as REQUEST_CHANGES
+
+    [*] --> ExistingReviewFound: Subsequent run (sentinel match)
+
+    ExistingReviewFound --> CheckEscalation: Determine final event
+    CheckEscalation --> CompareState: Apply worst-wins if needed
+
+    CompareState --> SameState: existing.state == new event
+    CompareState --> StateChange: existing.state != new event
+
+    SameState --> Skip: Body unchanged
+    SameState --> PatchBody: Body changed → PATCH in place
+
+    StateChange --> Escalate: APPROVED → REQUEST_CHANGES
+    StateChange --> Downgrade: REQUEST_CHANGES → APPROVED
+
+    Escalate --> Supersede: PATCH old body → "Superseded"
+    Supersede --> POST_New_RC: POST new REQUEST_CHANGES
+
+    Downgrade --> POST_New_Approve: POST new APPROVED (old stays intact)
+
+    Skip --> Done
+    PatchBody --> Done
+    POST_New_RC --> Done
+    POST_New_Approve --> Done
+```
+
+## Rules
+
+| Scenario | Action | Reason |
+|----------|--------|--------|
+| No existing review | POST new | First run |
+| Same state, same body | Skip | Nothing changed — preserve threads |
+| Same state, body changed | PATCH body | Update findings without losing threads |
+| APPROVED → REQUEST_CHANGES | Supersede old + POST new | Can always escalate; old APPROVED is no longer valid |
+| REQUEST_CHANGES → APPROVED | POST new APPROVED | Can't edit state; old REQUEST_CHANGES stays as historical record |
+| Sibling has REQUEST_CHANGES (worst-wins) | Escalate to REQUEST_CHANGES | PR must stay blocked if ANY reviewer blocks |
+
+## Key Constraints
+
+1. **Review state is immutable after POST** — Gitea has no API to change APPROVED ↔ REQUEST_CHANGES
+2. **Never delete reviews** — Deleting cascades to inline comments and reply threads
+3. **"Last review per user" wins** — Gitea uses the most recent review from a user for merge decisions
+4. **REQUEST_CHANGES reviews are never touched** — Their inline comments and threads are preserved as historical record
+5. **APPROVED reviews can be superseded** — When escalation is needed, mark old as superseded and POST new
+
+## Worst-Wins (Shared Token)
+
+When multiple reviewer roles share a token (e.g., `sonnet` and `security` both use `sonnet-review-bot`):
+
+```
+CI Matrix Run:
+  sonnet  → REQUEST_CHANGES (findings)
+  security → APPROVED (no security issues)
+                ↓
+  security sees sibling REQUEST_CHANGES
+                ↓
+  security escalates → REQUEST_CHANGES
+                ↓
+  PR stays blocked ✓
+```
+
+The **first-run case** (no existing review to read login from) uses a post-posting fallback:
+POST APPROVED → check siblings → if blocked, supersede own APPROVED → re-POST as REQUEST_CHANGES.
+
+## Edit Mechanism
+
+Reviews are edited via `PATCH /repos/{owner}/{repo}/issues/comments/{id}`:
+
+- **Review body**: ID obtained from the timeline API (`/issues/{index}/timeline`, type `"review"`)
+- **Inline comments**: IDs obtained from `/pulls/{index}/reviews/{id}/comments`
+- **Both are editable** by the token that created them
+- **ListReviews always returns the original body** (reads from review table, not comment table) — sentinel matching works regardless of edits
+
+## Inline Comments Lifecycle
+
+| Event | Inline comments behavior |
+|-------|--------------------------|
+| First POST | Created on specific diff lines |
+| PATCH body (same state) | Unchanged — still current findings |
+| Supersede (state change) | Old inline comments stay (readable but on outdated code) |
+| New POST after supersede | Fresh inline comments on current diff |

gitea/adapter.go

@@ -0,0 +1,316 @@
+package gitea
+
+import (
+	"context"
+	"fmt"
+	"log/slog"
+	"strings"
+
+	"gitea.weiker.me/rodin/review-bot/vcs"
+)
+
+// Adapter wraps a gitea.Client and satisfies the vcs.Client interface.
+// It handles translation between GitHub-canonical diff positions and Gitea
+// line numbers, and between canonical review event strings and Gitea-native values.
+type Adapter struct {
+	client *Client
+}
+
+// Compile-time interface conformance assertion.
+var _ vcs.Client = (*Adapter)(nil)
+var _ vcs.ReviewerSelfRequester = (*Adapter)(nil)
+
+// NewAdapter creates a new Adapter wrapping the given gitea Client.
+func NewAdapter(client *Client) *Adapter {
+	return &Adapter{client: client}
+}
+
+// Underlying returns the wrapped gitea.Client for Gitea-specific operations
+// that have no vcs.Client equivalent (resolve comment, timeline, supersede flow).
+func (a *Adapter) Underlying() *Client {
+	return a.client
+}
+
+// --- PRReader ---
+
+// GetPullRequest maps gitea.PullRequest to vcs.PullRequest.
+func (a *Adapter) GetPullRequest(ctx context.Context, owner, repo string, number int) (*vcs.PullRequest, error) {
+	pr, err := a.client.GetPullRequest(ctx, owner, repo, number)
+	if err != nil {
+		return nil, fmt.Errorf("get pull request: %w", err)
+	}
+	return &vcs.PullRequest{
+		Number: number,
+		Title:  pr.Title,
+		Body:   pr.Body,
+		Head: vcs.HeadRef{
+			SHA: pr.Head.Sha,
+			Ref: pr.Head.Ref,
+		},
+		Base: vcs.BaseRef{
+			Ref: pr.Base.Ref,
+		},
+	}, nil
+}
+
+// GetPullRequestDiff is a pass-through to the underlying client.
+func (a *Adapter) GetPullRequestDiff(ctx context.Context, owner, repo string, number int) (string, error) {
+	return a.client.GetPullRequestDiff(ctx, owner, repo, number)
+}
+
+// GetPullRequestFiles maps []gitea.ChangedFile to []vcs.ChangedFile.
+// Patch field is omitted (zero-value) since Gitea's /pulls/{n}/files does not return patch text.
+func (a *Adapter) GetPullRequestFiles(ctx context.Context, owner, repo string, number int) ([]vcs.ChangedFile, error) {
+	files, err := a.client.GetPullRequestFiles(ctx, owner, repo, number)
+	if err != nil {
+		return nil, err
+	}
+	result := make([]vcs.ChangedFile, len(files))
+	for i, f := range files {
+		result[i] = vcs.ChangedFile{
+			Filename: f.Filename,
+			Status:   f.Status,
+		}
+	}
+	return result, nil
+}
+
+// GetFileContentAtRef is a pass-through to the underlying client.
+func (a *Adapter) GetFileContentAtRef(ctx context.Context, owner, repo, path, ref string) (string, error) {
+	return a.client.GetFileContentAtRef(ctx, owner, repo, path, ref)
+}
+
+// GetCommitStatuses maps []gitea.CommitStatus to []vcs.CommitStatus.
+func (a *Adapter) GetCommitStatuses(ctx context.Context, owner, repo, sha string) ([]vcs.CommitStatus, error) {
+	statuses, err := a.client.GetCommitStatuses(ctx, owner, repo, sha)
+	if err != nil {
+		return nil, err
+	}
+	result := make([]vcs.CommitStatus, len(statuses))
+	for i, s := range statuses {
+		result[i] = vcs.CommitStatus{
+			Status:      s.Status,
+			Context:     s.Context,
+			Description: s.Description,
+			TargetURL:   s.TargetURL,
+		}
+	}
+	return result, nil
+}
+
+// --- FileReader ---
+
+// GetFileContent delegates to the underlying client, routing to the ref-aware
+// variant when ref is non-empty.
+func (a *Adapter) GetFileContent(ctx context.Context, owner, repo, path, ref string) (string, error) {
+	if ref != "" {
+		return a.client.GetFileContentRef(ctx, owner, repo, path, ref)
+	}
+	return a.client.GetFileContent(ctx, owner, repo, path)
+}
+
+// ListContents maps []gitea.ContentEntry to []vcs.ContentEntry.
+func (a *Adapter) ListContents(ctx context.Context, owner, repo, path string) ([]vcs.ContentEntry, error) {
+	entries, err := a.client.ListContents(ctx, owner, repo, path)
+	if err != nil {
+		return nil, err
+	}
+	result := make([]vcs.ContentEntry, len(entries))
+	for i, e := range entries {
+		result[i] = vcs.ContentEntry{
+			Name: e.Name,
+			Path: e.Path,
+			Type: e.Type,
+		}
+	}
+	return result, nil
+}
+
+// --- Reviewer ---
+
+// translateEvent translates a vcs.ReviewEvent (GitHub-canonical) to a Gitea-native event string.
+func translateEvent(event vcs.ReviewEvent) string {
+	switch event {
+	case vcs.ReviewEventApprove:
+		return "APPROVED"
+	case vcs.ReviewEventRequestChanges:
+		return "REQUEST_CHANGES"
+	case vcs.ReviewEventComment:
+		return "COMMENT"
+	default:
+		// Unknown events pass through as-is. This is intentional: new event types
+		// added to vcs.ReviewEvent will still be forwarded without a code change here,
+		// and Gitea will reject truly invalid values with a clear API error.
+		return string(event)
+	}
+}
+
+// PostReview translates vcs.ReviewRequest to the Gitea-native format.
+// It fetches the PR diff, builds a position-to-line map, and translates each
+// ReviewComment.Position (GitHub diff-position) to a Gitea new_position (line number).
+func (a *Adapter) PostReview(ctx context.Context, owner, repo string, number int, req vcs.ReviewRequest) (*vcs.Review, error) {
+	event := translateEvent(req.Event)
+
+	var giteaComments []ReviewComment
+	if len(req.Comments) > 0 {
+		// Fetch diff to build position → line number map.
+		// The diff is fetched unconditionally when comments exist. This adds latency
+		// for reviews with inline comments but keeps the implementation simple — caching
+		// the diff across calls would add complexity for minimal gain since PostReview
+		// is called at most once per review cycle.
+		diff, err := a.client.GetPullRequestDiff(ctx, owner, repo, number)
+		if err != nil {
+			return nil, fmt.Errorf("fetch diff for position translation: %w", err)
+		}
+
+		posMap := BuildPositionToLineMap(diff)
+
+		for _, c := range req.Comments {
+			lineNum, err := posMap.Translate(c.Path, c.Position)
+			if err != nil {
+				return nil, fmt.Errorf("translate position %d in %s: %w", c.Position, c.Path, err)
+			}
+			// Per-comment CommitID is not forwarded to Gitea inline comments:
+			// Gitea's CreatePullReview API has no per-comment commit_id field.
+			// The review-level commit anchor is set via req.CommitID instead.
+			giteaComments = append(giteaComments, ReviewComment{
+				Path:        c.Path,
+				NewPosition: int64(lineNum),
+				Body:        c.Body,
+			})
+		}
+	}
+
+	review, err := a.client.PostReview(ctx, owner, repo, number, event, req.Body, req.CommitID, giteaComments)
+	if err != nil {
+		return nil, fmt.Errorf("post review: %w", err)
+	}
+
+	return &vcs.Review{
+		ID:       review.ID,
+		Body:     review.Body,
+		User:     vcs.UserInfo{Login: review.User.Login},
+		State:    review.State,
+		Stale:    review.Stale,
+		CommitID: review.CommitID,
+	}, nil
+}
+
+// ListReviews maps []gitea.Review to []vcs.Review.
+func (a *Adapter) ListReviews(ctx context.Context, owner, repo string, number int) ([]vcs.Review, error) {
+	reviews, err := a.client.ListReviews(ctx, owner, repo, number)
+	if err != nil {
+		return nil, err
+	}
+	result := make([]vcs.Review, len(reviews))
+	for i, r := range reviews {
+		result[i] = vcs.Review{
+			ID:       r.ID,
+			Body:     r.Body,
+			User:     vcs.UserInfo{Login: r.User.Login},
+			State:    r.State,
+			Stale:    r.Stale,
+			CommitID: r.CommitID,
+		}
+	}
+	return result, nil
+}
+
+// DeleteReview is a pass-through to the underlying client.
+func (a *Adapter) DeleteReview(ctx context.Context, owner, repo string, number int, reviewID int64) error {
+	return a.client.DeleteReview(ctx, owner, repo, number, reviewID)
+}
+
+// DismissReview deletes the review. Gitea supports full deletion of any review state.
+// The message parameter is intentionally unused — Gitea deletion has no dismissal message.
+func (a *Adapter) DismissReview(ctx context.Context, owner, repo string, number int, reviewID int64, message string) error {
+	return a.client.DeleteReview(ctx, owner, repo, number, reviewID)
+}
+
+// --- Identity ---
+
+// GetAuthenticatedUser is a pass-through to the underlying client.
+func (a *Adapter) GetAuthenticatedUser(ctx context.Context) (string, error) {
+	return a.client.GetAuthenticatedUser(ctx)
+}
+
+// RequestReviewerSelf adds the given user as a requested reviewer on a pull request.
+// This implements vcs.ReviewerSelfRequester for the Gitea adapter.
+func (a *Adapter) RequestReviewerSelf(ctx context.Context, owner, repo string, number int, user string) error {
+	return a.client.RequestReviewer(ctx, owner, repo, number, user)
+}
+
+// Compile-time interface conformance assertion for ReviewSuperseder.
+var _ vcs.ReviewSuperseder = (*Adapter)(nil)
+
+// SupersedeReviews marks prior reviews as superseded by editing their body with a
+// link to the new review and resolving their inline comments. This is Gitea-specific
+// behavior that has no GitHub equivalent (GitHub uses DismissReview instead).
+//
+// baseURL is the Gitea instance URL used to construct review permalink URLs.
+// sentinel is the HTML comment sentinel that identifies reviews belonging to this reviewer.
+func (a *Adapter) SupersedeReviews(ctx context.Context, owner, repo string, prNumber int, oldReviews []vcs.Review, newReviewID int64, baseURL, sentinel string) error {
+	// Validate baseURL scheme before embedding in Markdown link (defense-in-depth).
+	if !strings.HasPrefix(baseURL, "http://") && !strings.HasPrefix(baseURL, "https://") {
+		return fmt.Errorf("SupersedeReviews: baseURL must have http or https scheme, got %q", baseURL)
+	}
+
+	underlying := a.client
+
+	newReviewURL := fmt.Sprintf("%s/%s/%s/pulls/%d#pullrequestreview-%d",
+		strings.TrimRight(baseURL, "/"), owner, repo, prNumber, newReviewID)
+
+	for _, oldReview := range oldReviews {
+		cid, err := underlying.GetTimelineReviewCommentIDForReview(ctx, owner, repo, prNumber, oldReview.ID)
+		if err != nil {
+			slog.Warn("could not find comment ID for old review", "review_id", oldReview.ID, "error", err)
+			continue
+		}
+		supersededBody := buildSupersededBody(oldReview.Body, oldReview.CommitID, newReviewURL, sentinel)
+		if err := underlying.EditComment(ctx, owner, repo, cid, supersededBody); err != nil {
+			slog.Warn("could not mark old review as superseded", "review_id", oldReview.ID, "error", err)
+			continue
+		}
+
+		// Resolve old review's inline comments
+		oldComments, err := underlying.ListReviewComments(ctx, owner, repo, prNumber, oldReview.ID)
+		if err != nil {
+			slog.Warn("could not list old review comments for resolution", "review_id", oldReview.ID, "error", err)
+			continue
+		}
+		for _, c := range oldComments {
+			if c.ID == 0 {
+				continue
+			}
+			if err := underlying.ResolveComment(ctx, owner, repo, c.ID); err != nil {
+				slog.Debug("could not resolve inline comment", "comment_id", c.ID, "error", err)
+			}
+		}
+	}
+	return nil
+}
+
+// buildSupersededBody creates the body for a superseded review: struck-through banner
+// with collapsed original content and the commit it was evaluated against.
+func buildSupersededBody(originalBody, commitSHA, newReviewURL, sentinel string) string {
+	shortSHA := commitSHA
+	if len(shortSHA) > 8 {
+		shortSHA = shortSHA[:8]
+	}
+	var sb strings.Builder
+	sb.WriteString("~~Original review~~\n\n")
+	sb.WriteString("**Superseded** \u2014 [see current review](")
+	sb.WriteString(newReviewURL)
+	sb.WriteString(") for up-to-date findings.\n\n")
+	if shortSHA != "" {
+		sb.WriteString("<details><summary>Previous findings (commit ")
+		sb.WriteString(shortSHA)
+		sb.WriteString(")</summary>\n\n")
+	} else {
+		sb.WriteString("<details><summary>Previous findings</summary>\n\n")
+	}
+	sb.WriteString(originalBody)
+	sb.WriteString("\n\n</details>\n\n")
+	sb.WriteString(sentinel)
+	return sb.String()
+}

gitea/adapter_test.go

@@ -0,0 +1,480 @@
+package gitea_test
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+
+	"gitea.weiker.me/rodin/review-bot/gitea"
+	"gitea.weiker.me/rodin/review-bot/vcs"
+)
+
+func TestAdapter_GetPullRequest(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/json")
+		json.NewEncoder(w).Encode(map[string]any{
+			"title": "Test PR",
+			"body":  "PR body",
+			"head": map[string]any{
+				"sha": "abc123",
+				"ref": "feature-branch",
+			},
+			"base": map[string]any{
+				"ref": "main",
+			},
+		})
+	}))
+	defer server.Close()
+
+	client := gitea.NewClient(server.URL, "token")
+	adapter := gitea.NewAdapter(client)
+
+	pr, err := adapter.GetPullRequest(context.Background(), "owner", "repo", 42)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if pr.Number != 42 {
+		t.Errorf("Number = %d, want 42", pr.Number)
+	}
+	if pr.Title != "Test PR" {
+		t.Errorf("Title = %q, want %q", pr.Title, "Test PR")
+	}
+	if pr.Body != "PR body" {
+		t.Errorf("Body = %q, want %q", pr.Body, "PR body")
+	}
+	if pr.Head.SHA != "abc123" {
+		t.Errorf("Head.SHA = %q, want %q", pr.Head.SHA, "abc123")
+	}
+	if pr.Head.Ref != "feature-branch" {
+		t.Errorf("Head.Ref = %q, want %q", pr.Head.Ref, "feature-branch")
+	}
+	if pr.Base.Ref != "main" {
+		t.Errorf("Base.Ref = %q, want %q", pr.Base.Ref, "main")
+	}
+}
+
+func TestAdapter_GetPullRequestFiles(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/json")
+		json.NewEncoder(w).Encode([]map[string]any{
+			{"filename": "main.go", "status": "modified"},
+			{"filename": "new.go", "status": "added"},
+		})
+	}))
+	defer server.Close()
+
+	client := gitea.NewClient(server.URL, "token")
+	adapter := gitea.NewAdapter(client)
+
+	files, err := adapter.GetPullRequestFiles(context.Background(), "owner", "repo", 1)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if len(files) != 2 {
+		t.Fatalf("got %d files, want 2", len(files))
+	}
+	if files[0].Filename != "main.go" || files[0].Status != "modified" {
+		t.Errorf("files[0] = %+v", files[0])
+	}
+	if files[1].Filename != "new.go" || files[1].Status != "added" {
+		t.Errorf("files[1] = %+v", files[1])
+	}
+}
+
+func TestAdapter_ListReviews(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/json")
+		json.NewEncoder(w).Encode([]map[string]any{
+			{
+				"id":        1,
+				"body":      "LGTM",
+				"user":      map[string]any{"login": "reviewer1"},
+				"state":     "APPROVED",
+				"stale":     false,
+				"commit_id": "abc123",
+			},
+			{
+				"id":        2,
+				"body":      "Needs work",
+				"user":      map[string]any{"login": "reviewer2"},
+				"state":     "REQUEST_CHANGES",
+				"stale":     true,
+				"commit_id": "def456",
+			},
+		})
+	}))
+	defer server.Close()
+
+	client := gitea.NewClient(server.URL, "token")
+	adapter := gitea.NewAdapter(client)
+
+	reviews, err := adapter.ListReviews(context.Background(), "owner", "repo", 1)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if len(reviews) != 2 {
+		t.Fatalf("got %d reviews, want 2", len(reviews))
+	}
+	if reviews[0].ID != 1 || reviews[0].Body != "LGTM" || reviews[0].User.Login != "reviewer1" {
+		t.Errorf("reviews[0] = %+v", reviews[0])
+	}
+	if reviews[0].State != "APPROVED" || reviews[0].Stale || reviews[0].CommitID != "abc123" {
+		t.Errorf("reviews[0] state/stale/commit = %v/%v/%v", reviews[0].State, reviews[0].Stale, reviews[0].CommitID)
+	}
+	if reviews[1].ID != 2 || !reviews[1].Stale || reviews[1].State != "REQUEST_CHANGES" {
+		t.Errorf("reviews[1] = %+v", reviews[1])
+	}
+}
+
+func TestAdapter_GetCommitStatuses(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/json")
+		json.NewEncoder(w).Encode([]map[string]any{
+			{
+				"status":      "success",
+				"context":     "ci/test",
+				"description": "All tests pass",
+				"target_url":  "https://ci.example.com/1",
+			},
+		})
+	}))
+	defer server.Close()
+
+	client := gitea.NewClient(server.URL, "token")
+	adapter := gitea.NewAdapter(client)
+
+	statuses, err := adapter.GetCommitStatuses(context.Background(), "owner", "repo", "abc123")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if len(statuses) != 1 {
+		t.Fatalf("got %d statuses, want 1", len(statuses))
+	}
+	if statuses[0].Status != "success" {
+		t.Errorf("Status = %q, want %q", statuses[0].Status, "success")
+	}
+	if statuses[0].Context != "ci/test" {
+		t.Errorf("Context = %q, want %q", statuses[0].Context, "ci/test")
+	}
+	if statuses[0].Description != "All tests pass" {
+		t.Errorf("Description = %q, want %q", statuses[0].Description, "All tests pass")
+	}
+	if statuses[0].TargetURL != "https://ci.example.com/1" {
+		t.Errorf("TargetURL = %q, want %q", statuses[0].TargetURL, "https://ci.example.com/1")
+	}
+}
+
+func TestAdapter_PostReview_EventTranslation(t *testing.T) {
+	tests := []struct {
+		name      string
+		event     vcs.ReviewEvent
+		wantEvent string
+	}{
+		{"APPROVE becomes APPROVED", vcs.ReviewEventApprove, "APPROVED"},
+		{"REQUEST_CHANGES stays", vcs.ReviewEventRequestChanges, "REQUEST_CHANGES"},
+		{"COMMENT stays", vcs.ReviewEventComment, "COMMENT"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			var gotEvent string
+			server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+				w.Header().Set("Content-Type", "application/json")
+				var payload struct {
+					Event string `json:"event"`
+				}
+				json.NewDecoder(r.Body).Decode(&payload)
+				gotEvent = payload.Event
+				json.NewEncoder(w).Encode(map[string]any{
+					"id":   1,
+					"body": "test",
+					"user": map[string]any{"login": "bot"},
+				})
+			}))
+			defer server.Close()
+
+			client := gitea.NewClient(server.URL, "token")
+			adapter := gitea.NewAdapter(client)
+
+			_, err := adapter.PostReview(context.Background(), "owner", "repo", 1, vcs.ReviewRequest{
+				Body:  "test",
+				Event: tt.event,
+				// No comments → no diff fetch needed
+			})
+			if err != nil {
+				t.Fatalf("unexpected error: %v", err)
+			}
+			if gotEvent != tt.wantEvent {
+				t.Errorf("event = %q, want %q", gotEvent, tt.wantEvent)
+			}
+		})
+	}
+}
+
+func TestAdapter_PostReview_WithComments_PositionTranslation(t *testing.T) {
+	diff := `diff --git a/main.go b/main.go
+--- a/main.go
++++ b/main.go
+@@ -1,3 +1,4 @@
+ package main
+ 
++// new comment at line 3
+ func main() {}
+`
+	var gotComments []struct {
+		Path        string `json:"path"`
+		NewPosition int64  `json:"new_position"`
+		Body        string `json:"body"`
+	}
+
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/json")
+		if strings.HasSuffix(r.URL.Path, ".diff") {
+			// Diff request
+			w.Write([]byte(diff))
+			return
+		}
+		if strings.HasSuffix(r.URL.Path, "/reviews") {
+			// Review post
+			var payload struct {
+				Comments []struct {
+					Path        string `json:"path"`
+					NewPosition int64  `json:"new_position"`
+					Body        string `json:"body"`
+				} `json:"comments"`
+			}
+			json.NewDecoder(r.Body).Decode(&payload)
+			gotComments = payload.Comments
+			json.NewEncoder(w).Encode(map[string]any{
+				"id":   1,
+				"body": "review",
+				"user": map[string]any{"login": "bot"},
+			})
+			return
+		}
+		t.Errorf("unexpected request: %s %s", r.Method, r.URL.Path)
+		w.WriteHeader(http.StatusNotFound)
+	}))
+	defer server.Close()
+
+	client := gitea.NewClient(server.URL, "token")
+	adapter := gitea.NewAdapter(client)
+
+	// Position 4 in this diff is "+// new comment at line 3" → new line 3
+	_, err := adapter.PostReview(context.Background(), "owner", "repo", 1, vcs.ReviewRequest{
+		Body:  "review",
+		Event: vcs.ReviewEventRequestChanges,
+		Comments: []vcs.ReviewComment{
+			{
+				Path:     "main.go",
+				Position: 4,
+				CommitID: "abc123",
+				Body:     "needs fix",
+			},
+		},
+	})
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	if len(gotComments) != 1 {
+		t.Fatalf("got %d comments, want 1", len(gotComments))
+	}
+	if gotComments[0].Path != "main.go" {
+		t.Errorf("path = %q, want %q", gotComments[0].Path, "main.go")
+	}
+	if gotComments[0].NewPosition != 3 {
+		t.Errorf("new_position = %d, want 3", gotComments[0].NewPosition)
+	}
+	if gotComments[0].Body != "needs fix" {
+		t.Errorf("body = %q, want %q", gotComments[0].Body, "needs fix")
+	}
+}
+
+func TestAdapter_DismissReview(t *testing.T) {
+	var deleteCalled bool
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.Method == http.MethodDelete {
+			deleteCalled = true
+			w.WriteHeader(204)
+			return
+		}
+		w.WriteHeader(404)
+	}))
+	defer server.Close()
+
+	client := gitea.NewClient(server.URL, "token")
+	adapter := gitea.NewAdapter(client)
+
+	err := adapter.DismissReview(context.Background(), "owner", "repo", 1, 99, "stale review")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if !deleteCalled {
+		t.Error("expected delete to be called")
+	}
+}
+
+func TestAdapter_Underlying(t *testing.T) {
+	client := gitea.NewClient("http://example.com", "token")
+	adapter := gitea.NewAdapter(client)
+	if adapter.Underlying() != client {
+		t.Error("Underlying() should return the wrapped client")
+	}
+}
+
+func TestAdapter_ListContents(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/json")
+		json.NewEncoder(w).Encode([]map[string]any{
+			{"name": "main.go", "path": "src/main.go", "type": "file"},
+			{"name": "util", "path": "src/util", "type": "dir"},
+		})
+	}))
+	defer server.Close()
+
+	client := gitea.NewClient(server.URL, "token")
+	adapter := gitea.NewAdapter(client)
+
+	entries, err := adapter.ListContents(context.Background(), "owner", "repo", "src")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if len(entries) != 2 {
+		t.Fatalf("got %d entries, want 2", len(entries))
+	}
+	if entries[0].Name != "main.go" || entries[0].Type != "file" {
+		t.Errorf("entries[0] = %+v", entries[0])
+	}
+	if entries[1].Name != "util" || entries[1].Type != "dir" {
+		t.Errorf("entries[1] = %+v", entries[1])
+	}
+}
+
+func TestAdapter_GetFileContent_RefRouting(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		// When ref is provided, the URL should contain ?ref=
+		if r.URL.RawQuery != "" && strings.Contains(r.URL.RawQuery, "ref=") {
+			w.Write([]byte("content-at-ref"))
+		} else {
+			w.Write([]byte("content-default"))
+		}
+	}))
+	defer server.Close()
+
+	client := gitea.NewClient(server.URL, "token")
+	adapter := gitea.NewAdapter(client)
+
+	// Empty ref → routes to GetFileContent (no ?ref= query param)
+	got, err := adapter.GetFileContent(context.Background(), "owner", "repo", "main.go", "")
+	if err != nil {
+		t.Fatalf("GetFileContent(ref=\"\"): %v", err)
+	}
+	if got != "content-default" {
+		t.Errorf("GetFileContent(ref=\"\") = %q, want %q", got, "content-default")
+	}
+
+	// Non-empty ref → routes to GetFileContentRef (with ?ref= query param)
+	got, err = adapter.GetFileContent(context.Background(), "owner", "repo", "main.go", "abc123")
+	if err != nil {
+		t.Fatalf("GetFileContent(ref=\"abc123\"): %v", err)
+	}
+	if got != "content-at-ref" {
+		t.Errorf("GetFileContent(ref=\"abc123\") = %q, want %q", got, "content-at-ref")
+	}
+}
+
+func TestAdapter_RequestReviewerSelf(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.Method != http.MethodPost {
+			t.Errorf("expected POST, got %s", r.Method)
+		}
+		expected := "/api/v1/repos/owner/repo/pulls/5/requested_reviewers"
+		if r.URL.Path != expected {
+			t.Errorf("path = %q, want %q", r.URL.Path, expected)
+		}
+		w.WriteHeader(http.StatusCreated)
+	}))
+	defer server.Close()
+
+	client := gitea.NewClient(server.URL, "token")
+	adapter := gitea.NewAdapter(client)
+
+	err := adapter.RequestReviewerSelf(context.Background(), "owner", "repo", 5, "bot-user")
+	if err != nil {
+		t.Fatalf("RequestReviewerSelf() error = %v", err)
+	}
+}
+
+func TestAdapter_PostReview_CommitID(t *testing.T) {
+	var gotPayload struct {
+		Body     string `json:"body"`
+		Event    string `json:"event"`
+		CommitID string `json:"commit_id"`
+	}
+
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/json")
+		json.NewDecoder(r.Body).Decode(&gotPayload)
+		json.NewEncoder(w).Encode(map[string]any{
+			"id":        1,
+			"body":      "test",
+			"user":      map[string]any{"login": "bot"},
+			"commit_id": "abc123def456",
+		})
+	}))
+	defer server.Close()
+
+	client := gitea.NewClient(server.URL, "token")
+	adapter := gitea.NewAdapter(client)
+
+	review, err := adapter.PostReview(context.Background(), "owner", "repo", 1, vcs.ReviewRequest{
+		Body:     "LGTM",
+		Event:    vcs.ReviewEventApprove,
+		CommitID: "abc123def456",
+		// No comments → no diff fetch needed
+	})
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if gotPayload.CommitID != "abc123def456" {
+		t.Errorf("commit_id = %q, want %q", gotPayload.CommitID, "abc123def456")
+	}
+	if review.CommitID != "abc123def456" {
+		t.Errorf("review.CommitID = %q, want %q", review.CommitID, "abc123def456")
+	}
+}
+
+func TestAdapter_PostReview_EmptyCommitID_Omitted(t *testing.T) {
+	var gotRawPayload map[string]any
+
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/json")
+		json.NewDecoder(r.Body).Decode(&gotRawPayload)
+		json.NewEncoder(w).Encode(map[string]any{
+			"id":   1,
+			"body": "test",
+			"user": map[string]any{"login": "bot"},
+		})
+	}))
+	defer server.Close()
+
+	client := gitea.NewClient(server.URL, "token")
+	adapter := gitea.NewAdapter(client)
+
+	_, err := adapter.PostReview(context.Background(), "owner", "repo", 1, vcs.ReviewRequest{
+		Body:  "looks good",
+		Event: vcs.ReviewEventComment,
+		// CommitID intentionally empty
+	})
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	// With empty CommitID and omitempty tag, the field should not appear in JSON
+	if _, exists := gotRawPayload["commit_id"]; exists {
+		t.Errorf("commit_id should be omitted when empty, but was present: %v", gotRawPayload["commit_id"])
+	}
+}

gitea/client.go

@@ -1,29 +1,83 @@
+// Package gitea provides a client for the Gitea API.
+// It supports pull request operations, file content retrieval,
+// and review submission.
 package gitea
 
 import (
+	"bytes"
+	"context"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io"
+	"log/slog"
+	"net"
 	"net/http"
+	"net/url"
 	"strings"
+	"syscall"
+	"time"
 )
 
+// APIError represents an HTTP error response from the Gitea API.
+// It carries the status code so callers can distinguish between
+// different failure modes (e.g. 404 vs 500).
+type APIError struct {
+	StatusCode int
+	Body       string
+}
+
+func (e *APIError) Error() string {
+	body := e.Body
+	if len(body) > 200 {
+		body = body[:200] + "...(truncated)"
+	}
+	return fmt.Sprintf("HTTP %d: %s", e.StatusCode, body)
+}
+
+// IsNotFound reports whether an error is an API 404 response.
+func IsNotFound(err error) bool {
+	var apiErr *APIError
+	return errors.As(err, &apiErr) && apiErr.StatusCode == http.StatusNotFound
+}
+
+// IsServerError reports whether an error is an API 5xx response.
+func IsServerError(err error) bool {
+	var apiErr *APIError
+	return errors.As(err, &apiErr) && apiErr.StatusCode >= 500 && apiErr.StatusCode < 600
+}
+
 // Client interacts with the Gitea API.
+// A Client is safe for concurrent use by multiple goroutines.
 type Client struct {
-	BaseURL string
-	Token   string
-	HTTP    *http.Client
+	baseURL string
+	token   string
+	http    *http.Client
+
+	// RetryBackoff defines the delays between retry attempts.
+	// RetryBackoff[i] is the delay before attempt i+1 (after attempt i fails).
+	// If nil, defaults to {1s, 2s}. Set to shorter durations in tests.
+	//
+	// This field must be configured before the first request is made.
+	// Modifying it while requests are in flight is not safe.
+	RetryBackoff []time.Duration
 }
 
 // NewClient creates a new Gitea API client.
 func NewClient(baseURL, token string) *Client {
 	return &Client{
-		BaseURL: strings.TrimRight(baseURL, "/"),
-		Token:   token,
-		HTTP:    &http.Client{},
+		baseURL: strings.TrimRight(baseURL, "/"),
+		token:   token,
+		http:    &http.Client{Timeout: 30 * time.Second},
 	}
 }
 
+// SetHTTPClient sets the underlying HTTP client used for requests.
+// This is intended for testing to inject mock transports.
+func (c *Client) SetHTTPClient(hc *http.Client) {
+	c.http = hc
+}
+
 // PullRequest holds relevant PR metadata.
 type PullRequest struct {
 	Title string `json:"title"`
@@ -32,6 +86,9 @@ type PullRequest struct {
 		Sha string `json:"sha"`
 		Ref string `json:"ref"`
 	} `json:"head"`
+	Base struct {
+		Ref string `json:"ref"`
+	} `json:"base"`
 }
 
 // CommitStatus represents a single CI status entry.
@@ -48,10 +105,18 @@ type ChangedFile struct {
 	Status   string `json:"status"`
 }
 
+// ReviewComment represents an inline comment to attach to a review.
+type ReviewComment struct {
+	ID          int64  `json:"id,omitempty"`
+	Path        string `json:"path"`
+	NewPosition int64  `json:"new_position"`
+	Body        string `json:"body"`
+}
+
 // GetPullRequest fetches PR metadata.
-func (c *Client) GetPullRequest(owner, repo string, number int) (*PullRequest, error) {
-	url := fmt.Sprintf("%s/api/v1/repos/%s/%s/pulls/%d", c.BaseURL, owner, repo, number)
-	body, err := c.doGet(url)
+func (c *Client) GetPullRequest(ctx context.Context, owner, repo string, number int) (*PullRequest, error) {
+	reqURL := fmt.Sprintf("%s/api/v1/repos/%s/%s/pulls/%d", c.baseURL, url.PathEscape(owner), url.PathEscape(repo), number)
+	body, err := c.doGet(ctx, reqURL)
 	if err != nil {
 		return nil, fmt.Errorf("fetch PR: %w", err)
 	}
@@ -63,9 +128,9 @@ func (c *Client) GetPullRequest(owner, repo string, number int) (*PullRequest, e
 }
 
 // GetPullRequestDiff fetches the unified diff for a PR.
-func (c *Client) GetPullRequestDiff(owner, repo string, number int) (string, error) {
-	url := fmt.Sprintf("%s/api/v1/repos/%s/%s/pulls/%d.diff", c.BaseURL, owner, repo, number)
-	body, err := c.doGet(url)
+func (c *Client) GetPullRequestDiff(ctx context.Context, owner, repo string, number int) (string, error) {
+	reqURL := fmt.Sprintf("%s/api/v1/repos/%s/%s/pulls/%d.diff", c.baseURL, url.PathEscape(owner), url.PathEscape(repo), number)
+	body, err := c.doGet(ctx, reqURL)
 	if err != nil {
 		return "", fmt.Errorf("fetch diff: %w", err)
 	}
@@ -73,9 +138,9 @@ func (c *Client) GetPullRequestDiff(owner, repo string, number int) (string, err
 }
 
 // GetPullRequestFiles fetches the list of files changed in a PR.
-func (c *Client) GetPullRequestFiles(owner, repo string, number int) ([]ChangedFile, error) {
-	url := fmt.Sprintf("%s/api/v1/repos/%s/%s/pulls/%d/files", c.BaseURL, owner, repo, number)
-	body, err := c.doGet(url)
+func (c *Client) GetPullRequestFiles(ctx context.Context, owner, repo string, number int) ([]ChangedFile, error) {
+	reqURL := fmt.Sprintf("%s/api/v1/repos/%s/%s/pulls/%d/files", c.baseURL, url.PathEscape(owner), url.PathEscape(repo), number)
+	body, err := c.doGet(ctx, reqURL)
 	if err != nil {
 		return nil, fmt.Errorf("fetch PR files: %w", err)
 	}
@@ -87,9 +152,9 @@ func (c *Client) GetPullRequestFiles(owner, repo string, number int) ([]ChangedF
 }
 
 // GetCommitStatuses fetches CI statuses for a commit SHA.
-func (c *Client) GetCommitStatuses(owner, repo, sha string) ([]CommitStatus, error) {
-	url := fmt.Sprintf("%s/api/v1/repos/%s/%s/commits/%s/statuses", c.BaseURL, owner, repo, sha)
-	body, err := c.doGet(url)
+func (c *Client) GetCommitStatuses(ctx context.Context, owner, repo, sha string) ([]CommitStatus, error) {
+	reqURL := fmt.Sprintf("%s/api/v1/repos/%s/%s/commits/%s/statuses", c.baseURL, url.PathEscape(owner), url.PathEscape(repo), url.PathEscape(sha))
+	body, err := c.doGet(ctx, reqURL)
 	if err != nil {
 		return nil, fmt.Errorf("fetch commit statuses: %w", err)
 	}
@@ -101,9 +166,9 @@ func (c *Client) GetCommitStatuses(owner, repo, sha string) ([]CommitStatus, err
 }
 
 // GetFileContent fetches a file from the default branch of a repo.
-func (c *Client) GetFileContent(owner, repo, filepath string) (string, error) {
-	url := fmt.Sprintf("%s/api/v1/repos/%s/%s/raw/%s", c.BaseURL, owner, repo, filepath)
-	body, err := c.doGet(url)
+func (c *Client) GetFileContent(ctx context.Context, owner, repo, filepath string) (string, error) {
+	reqURL := fmt.Sprintf("%s/api/v1/repos/%s/%s/raw/%s", c.baseURL, url.PathEscape(owner), url.PathEscape(repo), escapePath(filepath))
+	body, err := c.doGet(ctx, reqURL)
 	if err != nil {
 		return "", fmt.Errorf("fetch file %s: %w", filepath, err)
 	}
@@ -111,71 +176,260 @@ func (c *Client) GetFileContent(owner, repo, filepath string) (string, error) {
 }
 
 // GetFileContentRef fetches a file from a specific ref (branch/tag/sha) in a repo.
-func (c *Client) GetFileContentRef(owner, repo, filepath, ref string) (string, error) {
-	url := fmt.Sprintf("%s/api/v1/repos/%s/%s/raw/%s?ref=%s", c.BaseURL, owner, repo, filepath, ref)
-	body, err := c.doGet(url)
+func (c *Client) GetFileContentRef(ctx context.Context, owner, repo, filepath, ref string) (string, error) {
+	reqURL := fmt.Sprintf("%s/api/v1/repos/%s/%s/raw/%s?ref=%s", c.baseURL, url.PathEscape(owner), url.PathEscape(repo), escapePath(filepath), url.QueryEscape(ref))
+	body, err := c.doGet(ctx, reqURL)
 	if err != nil {
 		return "", fmt.Errorf("fetch file %s@%s: %w", filepath, ref, err)
 	}
 	return string(body), nil
 }
 
-// PostReview submits a review to a PR.
-// event should be "APPROVED" or "REQUEST_CHANGES".
-func (c *Client) PostReview(owner, repo string, number int, event, body string) error {
-	url := fmt.Sprintf("%s/api/v1/repos/%s/%s/pulls/%d/reviews", c.BaseURL, owner, repo, number)
+// PostReview submits a review to a PR and returns the created review.
+// event should be one of "APPROVED", "REQUEST_CHANGES", or "COMMENT".
+// commitID anchors the review to a specific commit SHA. If empty, Gitea
+// defaults to the current PR head.
+// comments are optional inline comments attached to specific lines.
+func (c *Client) PostReview(ctx context.Context, owner, repo string, number int, event, body, commitID string, comments []ReviewComment) (*Review, error) {
+	reqURL := fmt.Sprintf("%s/api/v1/repos/%s/%s/pulls/%d/reviews", c.baseURL, url.PathEscape(owner), url.PathEscape(repo), number)
 
 	payload := struct {
-		Body  string `json:"body"`
-		Event string `json:"event"`
+		Body     string          `json:"body"`
+		Event    string          `json:"event"`
+		CommitID string          `json:"commit_id,omitempty"`
+		Comments []ReviewComment `json:"comments,omitempty"`
 	}{
-		Body:  body,
-		Event: event,
+		Body:     body,
+		Event:    event,
+		CommitID: commitID,
+		Comments: comments,
 	}
 
 	data, err := json.Marshal(payload)
 	if err != nil {
-		return fmt.Errorf("marshal review payload: %w", err)
+		return nil, fmt.Errorf("marshal review payload: %w", err)
 	}
 
-	req, err := http.NewRequest("POST", url, strings.NewReader(string(data)))
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, reqURL, bytes.NewReader(data))
 	if err != nil {
-		return fmt.Errorf("create review request: %w", err)
+		return nil, fmt.Errorf("create review request: %w", err)
 	}
-	req.Header.Set("Authorization", "token "+c.Token)
+	req.Header.Set("Authorization", "token "+c.token)
 	req.Header.Set("Content-Type", "application/json")
 
-	resp, err := c.HTTP.Do(req)
+	resp, err := c.http.Do(req)
 	if err != nil {
-		return fmt.Errorf("post review: %w", err)
+		return nil, fmt.Errorf("post review: %w", err)
 	}
 	defer resp.Body.Close()
 
 	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
 		respBody, _ := io.ReadAll(resp.Body)
-		return fmt.Errorf("post review failed (status %d): %s", resp.StatusCode, string(respBody))
+		return nil, fmt.Errorf("post review failed (status %d): %s", resp.StatusCode, string(respBody))
 	}
-	return nil
+
+	respBody, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, fmt.Errorf("read review response: %w", err)
+	}
+	var review Review
+	if err := json.Unmarshal(respBody, &review); err != nil {
+		return nil, fmt.Errorf("parse review response: %w", err)
+	}
+	return &review, nil
 }
 
-func (c *Client) doGet(url string) ([]byte, error) {
-	req, err := http.NewRequest("GET", url, nil)
-	if err != nil {
-		return nil, err
+// isTemporaryNetError reports whether err is a temporary network error worth retrying.
+// This includes connection refused, network unreachable, connection reset, and DNS
+// timeouts. It explicitly excludes permanent errors like permission denied or
+// "no such host" DNS failures.
+func isTemporaryNetError(err error) bool {
+	if err == nil {
+		return false
 	}
-	req.Header.Set("Authorization", "token "+c.Token)
 
-	resp, err := c.HTTP.Do(req)
-	if err != nil {
-		return nil, err
+	// Check for OpError and inspect the underlying syscall error.
+	// Not all OpErrors are transient — permission denied, for example, is permanent.
+	var opErr *net.OpError
+	if errors.As(err, &opErr) {
+		return isRetriableSyscallError(opErr.Err)
 	}
-	defer resp.Body.Close()
 
-	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
-		body, _ := io.ReadAll(resp.Body)
-		return nil, fmt.Errorf("HTTP %d: %s", resp.StatusCode, string(body))
+	// DNS errors: only retry on timeout, not on "no such host" which is permanent.
+	var dnsErr *net.DNSError
+	if errors.As(err, &dnsErr) {
+		return dnsErr.IsTimeout
 	}
-	return io.ReadAll(resp.Body)
+
+	// Check for net.Error with Timeout() (Temporary is deprecated)
+	var netErr net.Error
+	if errors.As(err, &netErr) {
+		return netErr.Timeout()
+	}
+
+	return false
+}
+
+// isRetriableSyscallError reports whether the underlying error from a net.OpError
+// is a transient syscall error worth retrying.
+func isRetriableSyscallError(err error) bool {
+	if err == nil {
+		return false
+	}
+
+	// Check for syscall.Errno directly or wrapped
+	var errno syscall.Errno
+	if errors.As(err, &errno) {
+		switch errno {
+		case syscall.ECONNREFUSED, // connection refused — server not listening
+			syscall.ECONNRESET,   // connection reset by peer
+			syscall.ENETUNREACH,  // network unreachable
+			syscall.EHOSTUNREACH, // host unreachable
+			syscall.ETIMEDOUT:    // connection timed out
+			return true
+		default:
+			// EACCES, EPERM, etc. are permanent — don't retry
+			return false
+		}
+	}
+
+	// If we can't identify the specific syscall error, be conservative and retry.
+	// This handles wrapped errors or platform-specific error types.
+	// The retry count is limited, so erring on the side of retrying is safe.
+	return true
+}
+
+// redactURL strips query parameters from a URL for safe logging.
+// This prevents accidental exposure of sensitive data that future callers
+// might pass via query strings.
+func redactURL(rawURL string) string {
+	parsed, err := url.Parse(rawURL)
+	if err != nil {
+		// If we cannot parse it, return a safe placeholder rather than
+		// potentially logging something sensitive.
+		return "[invalid URL]"
+	}
+	if parsed.RawQuery != "" {
+		parsed.RawQuery = "[redacted]"
+	}
+	return parsed.String()
+}
+
+// sanitizeErrorForLog returns a loggable version of an error that omits
+// potentially sensitive content like response bodies. For APIError, only
+// the status code is included; for other errors, the type is preserved.
+func sanitizeErrorForLog(err error) string {
+	if err == nil {
+		return "<nil>"
+	}
+	var apiErr *APIError
+	if errors.As(err, &apiErr) {
+		return fmt.Sprintf("HTTP %d", apiErr.StatusCode)
+	}
+	return err.Error()
+}
+
+// doGet performs an HTTP GET request with retry on 5xx errors and temporary
+// network errors. Retries up to 3 times with exponential backoff (1s, 2s delays
+// by default; configurable via Client.RetryBackoff for testing).
+func (c *Client) doGet(ctx context.Context, reqURL string) ([]byte, error) {
+	const maxAttempts = 3
+	// backoff[i] is the delay before attempt i+1 (i.e., after attempt i fails).
+	// First attempt (i=0) has no delay; retries wait 1s then 2s by default.
+	backoff := c.RetryBackoff
+	if backoff == nil {
+		backoff = []time.Duration{1 * time.Second, 2 * time.Second}
+	}
+
+	// maxErrorBodyBytes limits how much of an error response body we read
+	// to protect against malicious servers sending unbounded data.
+	const maxErrorBodyBytes = 64 * 1024 // 64 KB
+
+	var lastErr error
+	for attempt := 0; attempt < maxAttempts; attempt++ {
+		if attempt > 0 {
+			// Determine delay: use backoff slice if available, otherwise retry immediately.
+			// An empty RetryBackoff slice means "retry without delay" — this is intentional
+			// as the caller explicitly configured no delays.
+			var delay time.Duration
+			if attempt-1 < len(backoff) {
+				delay = backoff[attempt-1]
+			}
+
+			if delay > 0 {
+				slog.Warn("retrying request after error",
+					"attempt", attempt+1,
+					"url", redactURL(reqURL),
+					"delay", delay.String(),
+					"lastError", sanitizeErrorForLog(lastErr))
+
+				timer := time.NewTimer(delay)
+				select {
+				case <-timer.C:
+				case <-ctx.Done():
+					timer.Stop()
+					return nil, ctx.Err()
+				}
+			}
+		}
+
+		req, err := http.NewRequestWithContext(ctx, http.MethodGet, reqURL, nil)
+		if err != nil {
+			return nil, err
+		}
+		req.Header.Set("Authorization", "token "+c.token)
+
+		resp, err := c.http.Do(req)
+		if err != nil {
+			// Always capture the error for consistent return at loop end.
+			// This ensures both network errors and HTTP 5xx return lastErr.
+			lastErr = err
+
+			// Only retry temporary network errors when attempts remain.
+			if attempt < maxAttempts-1 && isTemporaryNetError(err) {
+				slog.Warn("temporary network error, will retry",
+					"attempt", attempt+1,
+					"url", redactURL(reqURL),
+					"error", err)
+				continue
+			}
+			// Non-retryable network error or final attempt exhausted.
+			return nil, lastErr
+		}
+		if resp.StatusCode >= 200 && resp.StatusCode < 300 {
+			body, err := io.ReadAll(resp.Body)
+			resp.Body.Close()
+			if err != nil {
+				return nil, err
+			}
+			return body, nil
+		}
+
+		// Error path: limit how much we read from potentially malicious server
+		errBody, _ := io.ReadAll(io.LimitReader(resp.Body, maxErrorBodyBytes))
+		resp.Body.Close()
+
+		lastErr = &APIError{StatusCode: resp.StatusCode, Body: string(errBody)}
+
+		// Only retry on 5xx server errors
+		if resp.StatusCode < 500 || resp.StatusCode >= 600 {
+			return nil, lastErr
+		}
+	}
+
+	return nil, lastErr
+}
+
+// escapePath escapes each segment of a relative file path for use in URLs.
+// Slashes are preserved as path separators; other special characters are escaped.
+// Input should be a relative path (no leading slash). Already-encoded segments
+// will be double-encoded, which is the desired behavior for user-provided paths.
+func escapePath(p string) string {
+	parts := strings.Split(p, "/")
+	for i, part := range parts {
+		parts[i] = url.PathEscape(part)
+	}
+	return strings.Join(parts, "/")
 }
 
 // ContentEntry represents a file or directory entry from the contents API.
@@ -186,15 +440,36 @@ type ContentEntry struct {
 }
 
 // ListContents lists files and directories at a given path in a repo.
-func (c *Client) ListContents(owner, repo, path string) ([]ContentEntry, error) {
-	url := fmt.Sprintf("%s/api/v1/repos/%s/%s/contents/%s", c.BaseURL, owner, repo, path)
-	body, err := c.doGet(url)
+// Pass an empty path to list the repository root.
+// If the path points to a file (not a directory), Gitea returns a single
+// object instead of an array; this method normalizes both cases to a slice.
+func (c *Client) ListContents(ctx context.Context, owner, repo, path string) ([]ContentEntry, error) {
+	// Normalize "." to empty string — Gitea API rejects "." with 500
+	if path == "." {
+		path = ""
+	}
+	var reqURL string
+	if path == "" {
+		reqURL = fmt.Sprintf("%s/api/v1/repos/%s/%s/contents", c.baseURL, url.PathEscape(owner), url.PathEscape(repo))
+	} else {
+		reqURL = fmt.Sprintf("%s/api/v1/repos/%s/%s/contents/%s", c.baseURL, url.PathEscape(owner), url.PathEscape(repo), escapePath(path))
+	}
+	body, err := c.doGet(ctx, reqURL)
 	if err != nil {
 		return nil, fmt.Errorf("list contents %s: %w", path, err)
 	}
 	var entries []ContentEntry
 	if err := json.Unmarshal(body, &entries); err != nil {
-		return nil, fmt.Errorf("parse contents JSON: %w", err)
+		// Gitea returns a single object (not an array) when path is a file
+		var single ContentEntry
+		if err2 := json.Unmarshal(body, &single); err2 != nil {
+			return nil, fmt.Errorf("parse contents JSON: %w", err)
+		}
+		// Guard against empty/malformed responses
+		if single.Name == "" && single.Path == "" {
+			return nil, fmt.Errorf("parse contents JSON: empty response for path %q", path)
+		}
+		entries = []ContentEntry{single}
 	}
 	return entries, nil
 }
@@ -202,16 +477,21 @@ func (c *Client) ListContents(owner, repo, path string) ([]ContentEntry, error)
 // GetAllFilesInPath recursively fetches all file contents under a path.
 // If the path is a file, returns just that file's content.
 // If the path is a directory, recursively fetches all files within it.
-func (c *Client) GetAllFilesInPath(owner, repo, path string) (map[string]string, error) {
+func (c *Client) GetAllFilesInPath(ctx context.Context, owner, repo, path string) (map[string]string, error) {
 	results := make(map[string]string)
 
 	// Try listing as directory first
-	entries, err := c.ListContents(owner, repo, path)
+	entries, err := c.ListContents(ctx, owner, repo, path)
 	if err != nil {
-		// Might be a file, try fetching directly
-		content, fileErr := c.GetFileContent(owner, repo, path)
+		// Only fall back to single-file fetch on 404 (path is a file, not a dir).
+		// Propagate all other errors (auth failures, server errors, rate limits).
+		if !IsNotFound(err) {
+			return nil, fmt.Errorf("list contents %q: %w", path, err)
+		}
+		// 404 means the path might be a file — try fetching directly
+		content, fileErr := c.GetFileContent(ctx, owner, repo, path)
 		if fileErr != nil {
-			return nil, fmt.Errorf("path %q is neither a file nor directory: %w", path, err)
+			return nil, fmt.Errorf("path %q is neither a file nor directory: %w", path, fileErr)
 		}
 		results[path] = content
 		return results, nil
@@ -220,14 +500,16 @@ func (c *Client) GetAllFilesInPath(owner, repo, path string) (map[string]string,
 	for _, entry := range entries {
 		switch entry.Type {
 		case "file":
-			content, err := c.GetFileContent(owner, repo, entry.Path)
+			content, err := c.GetFileContent(ctx, owner, repo, entry.Path)
 			if err != nil {
-				continue // Skip files we can't read
+				slog.Warn("could not fetch file from patterns repo", "file", entry.Path, "error", err)
+				continue
 			}
 			results[entry.Path] = content
 		case "dir":
-			subResults, err := c.GetAllFilesInPath(owner, repo, entry.Path)
+			subResults, err := c.GetAllFilesInPath(ctx, owner, repo, entry.Path)
 			if err != nil {
+				slog.Warn("could not recurse into directory", "dir", entry.Path, "error", err)
 				continue
 			}
 			for k, v := range subResults {
@@ -237,3 +519,334 @@ func (c *Client) GetAllFilesInPath(owner, repo, path string) (map[string]string,
 	}
 	return results, nil
 }
+
+// Review represents a pull request review from the Gitea API.
+type Review struct {
+	ID   int64  `json:"id"`
+	Body string `json:"body"`
+	User struct {
+		Login string `json:"login"`
+	} `json:"user"`
+	State    string `json:"state"`
+	Stale    bool   `json:"stale"`
+	CommitID string `json:"commit_id"`
+}
+
+// ListReviews returns all reviews on a pull request.
+// Paginates through all pages to ensure no reviews are missed.
+func (c *Client) ListReviews(ctx context.Context, owner, repo string, number int) ([]Review, error) {
+	const pageSize = 50
+	var all []Review
+	for page := 1; ; page++ {
+		reqURL := fmt.Sprintf("%s/api/v1/repos/%s/%s/pulls/%d/reviews?limit=%d&page=%d",
+			c.baseURL,
+			url.PathEscape(owner),
+			url.PathEscape(repo),
+			number,
+			pageSize,
+			page)
+		body, err := c.doGet(ctx, reqURL)
+		if err != nil {
+			return nil, fmt.Errorf("list reviews (page %d): %w", page, err)
+		}
+		var batch []Review
+		if err := json.Unmarshal(body, &batch); err != nil {
+			return nil, fmt.Errorf("parse reviews (page %d): %w", page, err)
+		}
+		all = append(all, batch...)
+		if len(batch) < pageSize {
+			break
+		}
+	}
+	return all, nil
+}
+
+// DeleteReview deletes a review by ID. The token must belong to the review author.
+func (c *Client) DeleteReview(ctx context.Context, owner, repo string, number int, reviewID int64) error {
+	reqURL := fmt.Sprintf("%s/api/v1/repos/%s/%s/pulls/%d/reviews/%d",
+		c.baseURL,
+		url.PathEscape(owner),
+		url.PathEscape(repo),
+		number,
+		reviewID)
+
+	req, err := http.NewRequestWithContext(ctx, http.MethodDelete, reqURL, nil)
+	if err != nil {
+		return fmt.Errorf("create delete request: %w", err)
+	}
+	req.Header.Set("Authorization", "token "+c.token)
+
+	resp, err := c.http.Do(req)
+	if err != nil {
+		return fmt.Errorf("delete review: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
+		respBody, _ := io.ReadAll(resp.Body)
+		return fmt.Errorf("delete review failed (status %d): %s", resp.StatusCode, string(respBody))
+	}
+	return nil
+}
+
+// TimelineEvent represents an entry from the issue timeline API.
+type TimelineEvent struct {
+	ID   int64  `json:"id"`
+	Type string `json:"type"`
+	Body string `json:"body"`
+	User struct {
+		Login string `json:"login"`
+	} `json:"user"`
+}
+
+// GetTimelineReviewCommentID finds the comment ID for a review body by
+// scanning the issue timeline for a review event containing the sentinel.
+func (c *Client) GetTimelineReviewCommentID(ctx context.Context, owner, repo string, number int, sentinel string) (int64, error) {
+	const pageSize = 50
+	for page := 1; ; page++ {
+		reqURL := fmt.Sprintf("%s/api/v1/repos/%s/%s/issues/%d/timeline?limit=%d&page=%d",
+			c.baseURL,
+			url.PathEscape(owner),
+			url.PathEscape(repo),
+			number,
+			pageSize,
+			page)
+		body, err := c.doGet(ctx, reqURL)
+		if err != nil {
+			return 0, fmt.Errorf("get timeline (page %d): %w", page, err)
+		}
+		var events []TimelineEvent
+		if err := json.Unmarshal(body, &events); err != nil {
+			return 0, fmt.Errorf("parse timeline (page %d): %w", page, err)
+		}
+		for _, ev := range events {
+			if ev.Type == "review" && strings.Contains(ev.Body, sentinel) {
+				return ev.ID, nil
+			}
+		}
+		if len(events) < pageSize {
+			break
+		}
+	}
+	return 0, fmt.Errorf("no timeline event found with sentinel")
+}
+
+// GetTimelineReviewCommentIDForReview finds the timeline comment ID for a
+// specific review by matching its body content in the timeline.
+func (c *Client) GetTimelineReviewCommentIDForReview(ctx context.Context, owner, repo string, number int, reviewID int64) (int64, error) {
+	// Use the reviews API to get the review body, then find in timeline
+	reqURL := fmt.Sprintf("%s/api/v1/repos/%s/%s/pulls/%d/reviews/%d",
+		c.baseURL,
+		url.PathEscape(owner),
+		url.PathEscape(repo),
+		number,
+		reviewID)
+	body, err := c.doGet(ctx, reqURL)
+	if err != nil {
+		return 0, fmt.Errorf("get review %d: %w", reviewID, err)
+	}
+	var review struct {
+		Body string `json:"body"`
+		User struct {
+			Login string `json:"login"`
+		} `json:"user"`
+	}
+	if err := json.Unmarshal(body, &review); err != nil {
+		return 0, fmt.Errorf("parse review %d: %w", reviewID, err)
+	}
+	if review.Body == "" {
+		return 0, fmt.Errorf("review %d has empty body", reviewID)
+	}
+
+	// Use a prefix for matching (handles minor trailing whitespace differences)
+	matchPrefix := review.Body
+	if len(matchPrefix) > 200 {
+		matchPrefix = matchPrefix[:200]
+	}
+
+	const pageSize = 50
+	for page := 1; ; page++ {
+		timelineURL := fmt.Sprintf("%s/api/v1/repos/%s/%s/issues/%d/timeline?limit=%d&page=%d",
+			c.baseURL,
+			url.PathEscape(owner),
+			url.PathEscape(repo),
+			number,
+			pageSize,
+			page)
+		tlBody, err := c.doGet(ctx, timelineURL)
+		if err != nil {
+			return 0, fmt.Errorf("get timeline (page %d): %w", page, err)
+		}
+		var events []TimelineEvent
+		if err := json.Unmarshal(tlBody, &events); err != nil {
+			return 0, fmt.Errorf("parse timeline (page %d): %w", page, err)
+		}
+		for _, ev := range events {
+			if ev.Type == "review" && ev.User.Login == review.User.Login && strings.HasPrefix(ev.Body, matchPrefix) {
+				return ev.ID, nil
+			}
+		}
+		if len(events) < pageSize {
+			break
+		}
+	}
+	return 0, fmt.Errorf("no timeline event found for review %d", reviewID)
+}
+
+// EditComment updates the body of an issue/review comment.
+func (c *Client) EditComment(ctx context.Context, owner, repo string, commentID int64, newBody string) error {
+	reqURL := fmt.Sprintf("%s/api/v1/repos/%s/%s/issues/comments/%d",
+		c.baseURL,
+		url.PathEscape(owner),
+		url.PathEscape(repo),
+		commentID)
+
+	payload := struct {
+		Body string `json:"body"`
+	}{Body: newBody}
+	data, err := json.Marshal(payload)
+	if err != nil {
+		return fmt.Errorf("marshal edit payload: %w", err)
+	}
+
+	req, err := http.NewRequestWithContext(ctx, http.MethodPatch, reqURL, bytes.NewReader(data))
+	if err != nil {
+		return fmt.Errorf("create edit request: %w", err)
+	}
+	req.Header.Set("Authorization", "token "+c.token)
+	req.Header.Set("Content-Type", "application/json")
+
+	resp, err := c.http.Do(req)
+	if err != nil {
+		return fmt.Errorf("edit comment: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		body, _ := io.ReadAll(resp.Body)
+		return fmt.Errorf("edit comment failed (status %d): %s", resp.StatusCode, body)
+	}
+	return nil
+}
+
+// GetAuthenticatedUser returns the login of the user authenticated by the token.
+func (c *Client) GetAuthenticatedUser(ctx context.Context) (string, error) {
+	reqURL := fmt.Sprintf("%s/api/v1/user", c.baseURL)
+	body, err := c.doGet(ctx, reqURL)
+	if err != nil {
+		return "", fmt.Errorf("get authenticated user: %w", err)
+	}
+	var result struct {
+		Login string `json:"login"`
+	}
+	if err := json.Unmarshal(body, &result); err != nil {
+		return "", fmt.Errorf("parse user response: %w", err)
+	}
+	return result.Login, nil
+}
+
+// RequestReviewer adds the given user as a requested reviewer on a pull request.
+// This is idempotent — requesting an already-requested reviewer is a no-op.
+func (c *Client) RequestReviewer(ctx context.Context, owner, repo string, number int, reviewer string) error {
+	reqURL := fmt.Sprintf("%s/api/v1/repos/%s/%s/pulls/%d/requested_reviewers",
+		c.baseURL,
+		url.PathEscape(owner),
+		url.PathEscape(repo),
+		number)
+
+	payload := struct {
+		Reviewers []string `json:"reviewers"`
+	}{Reviewers: []string{reviewer}}
+	data, err := json.Marshal(payload)
+	if err != nil {
+		return fmt.Errorf("marshal reviewer request: %w", err)
+	}
+
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, reqURL, bytes.NewReader(data))
+	if err != nil {
+		return fmt.Errorf("create reviewer request: %w", err)
+	}
+	req.Header.Set("Authorization", "token "+c.token)
+	req.Header.Set("Content-Type", "application/json")
+
+	resp, err := c.http.Do(req)
+	if err != nil {
+		return fmt.Errorf("request reviewer: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK && resp.StatusCode != http.StatusCreated && resp.StatusCode != http.StatusNoContent {
+		body, _ := io.ReadAll(io.LimitReader(resp.Body, 256))
+		return fmt.Errorf("request reviewer failed (status %d): %s", resp.StatusCode, body)
+	}
+	return nil
+}
+
+// ListReviewComments returns the inline comments attached to a specific review.
+// Paginates through all pages.
+func (c *Client) ListReviewComments(ctx context.Context, owner, repo string, prNumber int, reviewID int64) ([]ReviewComment, error) {
+	const pageSize = 50
+	var all []ReviewComment
+	for page := 1; ; page++ {
+		reqURL := fmt.Sprintf("%s/api/v1/repos/%s/%s/pulls/%d/reviews/%d/comments?limit=%d&page=%d",
+			c.baseURL,
+			url.PathEscape(owner),
+			url.PathEscape(repo),
+			prNumber,
+			reviewID,
+			pageSize,
+			page)
+		body, err := c.doGet(ctx, reqURL)
+		if err != nil {
+			return nil, fmt.Errorf("list review comments (page %d): %w", page, err)
+		}
+		var batch []ReviewComment
+		if err := json.Unmarshal(body, &batch); err != nil {
+			return nil, fmt.Errorf("parse review comments (page %d): %w", page, err)
+		}
+		all = append(all, batch...)
+		if len(batch) < pageSize {
+			break
+		}
+	}
+	return all, nil
+}
+
+// ResolveComment marks an inline review comment as resolved.
+func (c *Client) ResolveComment(ctx context.Context, owner, repo string, commentID int64) error {
+	reqURL := fmt.Sprintf("%s/api/v1/repos/%s/%s/pulls/comments/%d/resolve",
+		c.baseURL,
+		url.PathEscape(owner),
+		url.PathEscape(repo),
+		commentID)
+
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, reqURL, nil)
+	if err != nil {
+		return fmt.Errorf("create resolve request: %w", err)
+	}
+	req.Header.Set("Authorization", "token "+c.token)
+
+	resp, err := c.http.Do(req)
+	if err != nil {
+		return fmt.Errorf("resolve comment: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK && resp.StatusCode != http.StatusCreated && resp.StatusCode != http.StatusNoContent {
+		body, _ := io.ReadAll(io.LimitReader(resp.Body, 256))
+		return fmt.Errorf("resolve comment failed (status %d): %s", resp.StatusCode, body)
+	}
+	return nil
+}
+
+// DismissReview dismisses a review on a pull request.
+// This is a stub for the vcs.Reviewer interface; full implementation is Phase 2.
+func (c *Client) DismissReview(ctx context.Context, owner, repo string, number int, reviewID int64, message string) error {
+	return fmt.Errorf("dismiss review %d on %s/%s#%d: %w", reviewID, owner, repo, number, errors.ErrUnsupported)
+}
+
+// GetFileContentAtRef fetches a file at a specific ref from a repo.
+// This delegates to GetFileContentRef for the Gitea implementation.
+func (c *Client) GetFileContentAtRef(ctx context.Context, owner, repo, path, ref string) (string, error) {
+	return c.GetFileContentRef(ctx, owner, repo, path, ref)
+}

gitea/conformance_test.go

@@ -0,0 +1,10 @@
+package gitea_test
+
+import (
+	"gitea.weiker.me/rodin/review-bot/gitea"
+	"gitea.weiker.me/rodin/review-bot/vcs"
+)
+
+// Compile-time interface conformance assertion.
+// The Adapter (not the raw Client) satisfies the full vcs.Client interface.
+var _ vcs.Client = (*gitea.Adapter)(nil)

gitea/diff.go

@@ -0,0 +1,85 @@
+package gitea
+
+import (
+	"strconv"
+	"strings"
+)
+
+// DiffLineRanges maps filenames to the set of new-file line numbers present in the diff.
+type DiffLineRanges struct {
+	files map[string]map[int]bool
+}
+
+// Contains reports whether the given file+line is within the diff hunks.
+func (d *DiffLineRanges) Contains(file string, line int) bool {
+	if d == nil || d.files == nil {
+		return false
+	}
+	lines, ok := d.files[file]
+	if !ok {
+		return false
+	}
+	return lines[line]
+}
+
+// ParseDiffNewLines parses a unified diff and extracts the new-file line numbers
+// that appear in each hunk (both added and context lines).
+func ParseDiffNewLines(diff string) *DiffLineRanges {
+	result := &DiffLineRanges{files: make(map[string]map[int]bool)}
+
+	var currentFile string
+	var newLine int
+
+	for _, line := range strings.Split(diff, "\n") {
+		// Track current file from +++ header
+		if strings.HasPrefix(line, "+++ b/") {
+			currentFile = strings.TrimPrefix(line, "+++ b/")
+			if result.files[currentFile] == nil {
+				result.files[currentFile] = make(map[int]bool)
+			}
+			continue
+		}
+		if strings.HasPrefix(line, "+++ /dev/null") {
+			currentFile = ""
+			continue
+		}
+
+		// Parse hunk header: @@ -old,count +new,count @@ or @@ -old +new @@
+		if strings.HasPrefix(line, "@@") && currentFile != "" {
+			// Extract the +N part — handle both "+10,8" and "+1" forms
+			parts := strings.Split(line, "+")
+			if len(parts) >= 2 {
+				// Take everything before comma or space
+				numStr := parts[1]
+				if idx := strings.IndexAny(numStr, ", "); idx != -1 {
+					numStr = numStr[:idx]
+				}
+				n, err := strconv.Atoi(numStr)
+				if err == nil {
+					newLine = n
+				}
+			}
+			continue
+		}
+
+		if currentFile == "" {
+			continue
+		}
+
+		// Skip diff metadata lines
+		if strings.HasPrefix(line, "\\") {
+			continue
+		}
+
+		// Count lines in hunk
+		if strings.HasPrefix(line, "+") || strings.HasPrefix(line, " ") {
+			result.files[currentFile][newLine] = true
+			newLine++
+		} else if strings.HasPrefix(line, "-") {
+			// Removed lines don't advance new line counter
+			continue
+		}
+	}
+
+	return result
+}

gitea/diff_test.go

@@ -0,0 +1,115 @@
+package gitea
+
+import (
+	"testing"
+)
+
+func TestParseDiffLineRanges(t *testing.T) {
+	diff := `diff --git a/main.go b/main.go
+index abc1234..def5678 100644
+--- a/main.go
++++ b/main.go
+@@ -10,6 +10,8 @@ func main() {
+ 	fmt.Println("hello")
++	fmt.Println("new line 11")
++	fmt.Println("new line 12")
+ 	fmt.Println("existing")
+ }
+@@ -30,4 +32,5 @@ func other() {
+ 	return nil
++	// added at line 33
+ }
+diff --git a/util.go b/util.go
+new file mode 100644
+--- /dev/null
++++ b/util.go
+@@ -0,0 +1,5 @@
++package main
++
++func helper() string {
++	return "hi"
++}
+`
+
+	ranges := ParseDiffNewLines(diff)
+
+	// main.go should have lines 10-17 (first hunk) and 32-36 (second hunk)
+	if !ranges.Contains("main.go", 11) {
+		t.Error("expected main.go:11 to be in diff")
+	}
+	if !ranges.Contains("main.go", 12) {
+		t.Error("expected main.go:12 to be in diff")
+	}
+	if !ranges.Contains("main.go", 10) {
+		t.Error("expected main.go:10 to be in diff (context line)")
+	}
+	if !ranges.Contains("main.go", 33) {
+		t.Error("expected main.go:33 to be in diff")
+	}
+	if ranges.Contains("main.go", 25) {
+		t.Error("main.go:25 should NOT be in diff")
+	}
+
+	// util.go is entirely new, lines 1-5
+	if !ranges.Contains("util.go", 1) {
+		t.Error("expected util.go:1 to be in diff")
+	}
+	if !ranges.Contains("util.go", 5) {
+		t.Error("expected util.go:5 to be in diff")
+	}
+	if ranges.Contains("util.go", 6) {
+		t.Error("util.go:6 should NOT be in diff")
+	}
+
+	// Unknown file
+	if ranges.Contains("unknown.go", 1) {
+		t.Error("unknown.go should not be in diff")
+	}
+}
+
+func TestParseDiffNewLines_Empty(t *testing.T) {
+	ranges := ParseDiffNewLines("")
+	if ranges.Contains("any.go", 1) {
+		t.Error("empty diff should contain nothing")
+	}
+}
+
+func TestParseDiffNewLines_NoCommaHunk(t *testing.T) {
+	// Single-line hunks omit the comma: @@ -1 +1 @@
+	diff := `diff --git a/single.go b/single.go
+--- a/single.go
++++ b/single.go
+@@ -1 +1 @@
+-old line
++new line
+`
+	ranges := ParseDiffNewLines(diff)
+	if !ranges.Contains("single.go", 1) {
+		t.Error("expected single.go:1 to be in diff (no-comma hunk)")
+	}
+	if ranges.Contains("single.go", 2) {
+		t.Error("single.go:2 should NOT be in diff")
+	}
+}
+
+func TestParseDiffNewLines_NoNewlineMarker(t *testing.T) {
+	// "\ No newline at end of file" should not advance line counter
+	diff := `diff --git a/noeof.go b/noeof.go
+--- a/noeof.go
++++ b/noeof.go
+@@ -1,2 +1,2 @@
++line one
++line two
+\ No newline at end of file
+`
+	ranges := ParseDiffNewLines(diff)
+	if !ranges.Contains("noeof.go", 1) {
+		t.Error("expected noeof.go:1")
+	}
+	if !ranges.Contains("noeof.go", 2) {
+		t.Error("expected noeof.go:2")
+	}
+	if ranges.Contains("noeof.go", 3) {
+		t.Error("noeof.go:3 should NOT be in diff (no-newline marker)")
+	}
+}

gitea/position.go

@@ -0,0 +1,197 @@
+package gitea
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+)
+
+// PositionMap holds a per-file mapping of GitHub diff-position to new-file line number.
+// Position is a 1-indexed offset from the @@ hunk header line in the unified diff.
+type PositionMap struct {
+	// files maps filename → (position → new-file line number).
+	// Deletion lines are mapped to -1 (no new-file line).
+	// Hunk-header lines are mapped to 0 (no new-file line).
+	files map[string]map[int]int
+	// maxPositions caches the highest position number per file,
+	// tracked during construction to avoid O(n) scans at translate time.
+	maxPositions map[string]int
+}
+
+// Translate converts a GitHub diff-position to a new-file line number for a given file.
+// Returns an error if the file is not in the diff or the position is out of range.
+// If the position targets a deletion or hunk-header line, it maps to the nearest
+// context/addition line below; if no such line exists, returns an error.
+func (pm *PositionMap) Translate(file string, position int) (int, error) {
+	if pm == nil || pm.files == nil {
+		return 0, fmt.Errorf("empty position map")
+	}
+
+	fileMap, ok := pm.files[file]
+	if !ok {
+		return 0, fmt.Errorf("file %q not found in diff", file)
+	}
+
+	if position < 1 {
+		return 0, fmt.Errorf("position %d out of range (must be >= 1)", position)
+	}
+
+	lineNum, ok := fileMap[position]
+	if !ok {
+		return 0, fmt.Errorf("position %d out of range for file %q", position, file)
+	}
+
+	// lineNum == -1 means this position is a deletion line.
+	// lineNum == 0 means this position is a hunk-header line.
+	// Both map to the nearest context/addition line below.
+	if lineNum <= 0 {
+		maxPos := pm.maxPosition(file)
+		for p := position + 1; p <= maxPos; p++ {
+			if ln, exists := fileMap[p]; exists && ln > 0 {
+				return ln, nil
+			}
+		}
+		if lineNum == 0 {
+			return 0, fmt.Errorf("position %d targets a hunk-header line with no subsequent new-file line in %q", position, file)
+		}
+		return 0, fmt.Errorf("position %d targets a deletion line with no subsequent new-file line in %q", position, file)
+	}
+
+	return lineNum, nil
+}
+
+// maxPosition returns the highest position number for a file.
+// O(1) — the maximum is tracked during map construction.
+func (pm *PositionMap) maxPosition(file string) int {
+	return pm.maxPositions[file]
+}
+
+// BuildPositionToLineMap parses a unified diff and builds a PositionMap
+// mapping diff-position → new-file line number per file.
+//
+// Diff-position counting rules (GitHub spec):
+//   - The @@ hunk header line is position 1 for the file's first hunk
+//   - Every subsequent line increments position by 1 — context, additions, AND deletions
+//   - A new @@ hunk within the same file continues incrementing (does not reset)
+//   - Position maps to the new file line number for additions and context lines
+//   - Deletion lines have a position but no new-file line number (stored as -1)
+//   - Hunk-header lines have a position but no new-file line number (stored as 0)
+func BuildPositionToLineMap(diff string) *PositionMap {
+	pm := &PositionMap{
+		files:        make(map[string]map[int]int),
+		maxPositions: make(map[string]int),
+	}
+
+	lines := strings.Split(diff, "\n")
+	var currentFile string
+	var position int
+	var newLine int
+
+	for _, line := range lines {
+		// Detect new file in diff.
+		// "+++ b/" is checked before "+++ /dev/null" — the two prefixes are
+		// non-overlapping ("+++ /dev/null" does not start with "+++ b/"), so
+		// ordering is independent. Checking the common case first for clarity.
+		if strings.HasPrefix(line, "+++ b/") {
+			currentFile = strings.TrimPrefix(line, "+++ b/")
+			position = 0
+			newLine = 0
+			if pm.files[currentFile] == nil {
+				pm.files[currentFile] = make(map[int]int)
+			}
+			continue
+		}
+
+		// Deleted file: +++ /dev/null means the file is being deleted
+		if strings.HasPrefix(line, "+++ /dev/null") {
+			currentFile = ""
+			continue
+		}
+
+		// Skip --- lines (old file header)
+		if strings.HasPrefix(line, "--- ") {
+			continue
+		}
+
+		// Skip diff --git lines
+		if strings.HasPrefix(line, "diff --git") {
+			continue
+		}
+
+		// Skip index lines
+		if strings.HasPrefix(line, "index ") {
+			continue
+		}
+
+		// Binary file detection
+		if strings.HasPrefix(line, "Binary files") {
+			currentFile = ""
+			continue
+		}
+
+		// Parse hunk headers
+		if strings.HasPrefix(line, "@@") && currentFile != "" {
+			position++
+			pm.files[currentFile][position] = 0 // sentinel: hunk-header has no new-file line
+			pm.maxPositions[currentFile] = position
+			newLine = parseHunkStart(line)
+			continue
+		}
+
+		if currentFile == "" {
+			continue
+		}
+
+		// Skip "\ No newline at end of file" markers
+		if strings.HasPrefix(line, `\`) {
+			continue
+		}
+
+		// Process diff content lines
+		if strings.HasPrefix(line, "+") {
+			// Addition: has a new-file line number
+			position++
+			pm.files[currentFile][position] = newLine
+			pm.maxPositions[currentFile] = position
+			newLine++
+		} else if strings.HasPrefix(line, "-") {
+			// Deletion: has a position but no new-file line number
+			position++
+			pm.files[currentFile][position] = -1
+			pm.maxPositions[currentFile] = position
+		} else if strings.HasPrefix(line, " ") {
+			// Context line
+			position++
+			pm.files[currentFile][position] = newLine
+			pm.maxPositions[currentFile] = position
+			newLine++
+		}
+	}
+
+	return pm
+}
+
+// parseHunkStart extracts the new-file starting line number from a hunk header.
+// Format: @@ -old_start[,old_count] +new_start[,new_count] @@
+func parseHunkStart(hunkLine string) int {
+	plusIdx := strings.Index(hunkLine, "+")
+	if plusIdx < 0 {
+		return 1
+	}
+	rest := hunkLine[plusIdx+1:]
+
+	endIdx := 0
+	for endIdx < len(rest) && rest[endIdx] >= '0' && rest[endIdx] <= '9' {
+		endIdx++
+	}
+
+	if endIdx == 0 {
+		return 1
+	}
+
+	n, err := strconv.Atoi(rest[:endIdx])
+	if err != nil {
+		return 1
+	}
+	return n
+}

gitea/position_test.go

@@ -0,0 +1,383 @@
+package gitea
+
+import (
+	"testing"
+)
+
+func TestBuildPositionToLineMap_SingleHunk(t *testing.T) {
+	// @@ -16,4 +16,5 @@  ← position 1
+	// context           ← position 2, new line 16
+	//-deleted           ← position 3, no new line
+	//+added             ← position 4, new line 17
+	// context           ← position 5, new line 18
+	diff := `diff --git a/file.go b/file.go
+index abc..def 100644
+--- a/file.go
++++ b/file.go
+@@ -16,4 +16,5 @@ func example() {
+ context line
+-deleted line
++added line
+ context after
+`
+	pm := BuildPositionToLineMap(diff)
+
+	tests := []struct {
+		pos      int
+		wantLine int
+	}{
+		{2, 16}, // context line -> new line 16
+		{4, 17}, // added line -> new line 17
+		{5, 18}, // context after -> new line 18
+	}
+	for _, tt := range tests {
+		got, err := pm.Translate("file.go", tt.pos)
+		if err != nil {
+			t.Errorf("Translate(file.go, %d): unexpected error: %v", tt.pos, err)
+			continue
+		}
+		if got != tt.wantLine {
+			t.Errorf("Translate(file.go, %d) = %d, want %d", tt.pos, got, tt.wantLine)
+		}
+	}
+}
+
+func TestBuildPositionToLineMap_MultipleHunks(t *testing.T) {
+	diff := `diff --git a/file.go b/file.go
+--- a/file.go
++++ b/file.go
+@@ -1,3 +1,3 @@ package main
+ line1
+-old
++new
+@@ -10,3 +10,4 @@ func foo() {
+ func foo() {
++	// added
+ 	return
+ }
+`
+	pm := BuildPositionToLineMap(diff)
+
+	tests := []struct {
+		pos      int
+		wantLine int
+	}{
+		// First hunk: @@ is pos 1
+		{2, 1},  // " line1" -> new line 1
+		{4, 2},  // "+new" -> new line 2
+		// Second hunk: @@ is pos 5 (continues from 4)
+		// Wait: first hunk has pos 1(@@ hdr), 2(" line1"), 3("-old"), 4("+new")
+		// Second hunk @@ is pos 5
+		{6, 10}, // " func foo() {" -> new line 10
+		{7, 11}, // "+\t// added" -> new line 11
+		{8, 12}, // " \treturn" -> new line 12
+		{9, 13}, // " }" -> new line 13
+	}
+	for _, tt := range tests {
+		got, err := pm.Translate("file.go", tt.pos)
+		if err != nil {
+			t.Errorf("Translate(file.go, %d): unexpected error: %v", tt.pos, err)
+			continue
+		}
+		if got != tt.wantLine {
+			t.Errorf("Translate(file.go, %d) = %d, want %d", tt.pos, got, tt.wantLine)
+		}
+	}
+}
+
+func TestBuildPositionToLineMap_DeletionTargeted(t *testing.T) {
+	diff := `diff --git a/file.go b/file.go
+--- a/file.go
++++ b/file.go
+@@ -1,4 +1,3 @@ package main
+ line1
+-deleted
+ line3
+`
+	pm := BuildPositionToLineMap(diff)
+
+	// Position 3 is the deletion line "-deleted" — should map to nearest below
+	// Position 4 is " line3" which is new line 2
+	got, err := pm.Translate("file.go", 3)
+	if err != nil {
+		t.Fatalf("Translate(file.go, 3): unexpected error: %v", err)
+	}
+	if got != 2 {
+		t.Errorf("Translate(file.go, 3) = %d, want 2 (nearest non-deletion below)", got)
+	}
+}
+
+func TestBuildPositionToLineMap_DeletionAtEnd(t *testing.T) {
+	// If a deletion line is at the end with no subsequent non-deletion line, error
+	diff := `diff --git a/file.go b/file.go
+--- a/file.go
++++ b/file.go
+@@ -1,3 +1,2 @@ package main
+ line1
+ line2
+-deleted at end
+`
+	pm := BuildPositionToLineMap(diff)
+
+	_, err := pm.Translate("file.go", 4)
+	if err == nil {
+		t.Error("expected error for deletion at end with no subsequent line")
+	}
+}
+
+func TestBuildPositionToLineMap_NewFile(t *testing.T) {
+	diff := `diff --git a/new.go b/new.go
+new file mode 100644
+--- /dev/null
++++ b/new.go
+@@ -0,0 +1,3 @@
++package main
++
++func init() {}
+`
+	pm := BuildPositionToLineMap(diff)
+
+	tests := []struct {
+		pos      int
+		wantLine int
+	}{
+		{2, 1}, // "+package main" -> line 1
+		{3, 2}, // "+" (empty line) -> line 2
+		{4, 3}, // "+func init() {}" -> line 3
+	}
+	for _, tt := range tests {
+		got, err := pm.Translate("new.go", tt.pos)
+		if err != nil {
+			t.Errorf("Translate(new.go, %d): unexpected error: %v", tt.pos, err)
+			continue
+		}
+		if got != tt.wantLine {
+			t.Errorf("Translate(new.go, %d) = %d, want %d", tt.pos, got, tt.wantLine)
+		}
+	}
+}
+
+func TestBuildPositionToLineMap_DeletedFile(t *testing.T) {
+	diff := `diff --git a/old.go b/old.go
+deleted file mode 100644
+--- a/old.go
++++ /dev/null
+@@ -1,3 +0,0 @@
+-package main
+-
+-func old() {}
+`
+	pm := BuildPositionToLineMap(diff)
+
+	// Deleted file has no new-file lines; positions should error
+	_, err := pm.Translate("old.go", 2)
+	if err == nil {
+		t.Error("expected error for deleted file position")
+	}
+}
+
+func TestBuildPositionToLineMap_BinaryFile(t *testing.T) {
+	diff := `diff --git a/image.png b/image.png
+Binary files /dev/null and b/image.png differ
+diff --git a/code.go b/code.go
+--- a/code.go
++++ b/code.go
+@@ -1,2 +1,3 @@
+ package main
++// added
+ func main() {}
+`
+	pm := BuildPositionToLineMap(diff)
+
+	// Binary file should not be in the map
+	_, err := pm.Translate("image.png", 1)
+	if err == nil {
+		t.Error("expected error for binary file")
+	}
+
+	// code.go should still work
+	got, err := pm.Translate("code.go", 3)
+	if err != nil {
+		t.Fatalf("Translate(code.go, 3): unexpected error: %v", err)
+	}
+	if got != 2 {
+		t.Errorf("Translate(code.go, 3) = %d, want 2", got)
+	}
+}
+
+func TestBuildPositionToLineMap_OutOfRange(t *testing.T) {
+	diff := `diff --git a/file.go b/file.go
+--- a/file.go
++++ b/file.go
+@@ -1,2 +1,2 @@
+ line1
+-old
++new
+`
+	pm := BuildPositionToLineMap(diff)
+
+	// Position 0 is invalid
+	_, err := pm.Translate("file.go", 0)
+	if err == nil {
+		t.Error("expected error for position 0")
+	}
+
+	// Position 5 is out of range (only positions 1-4 exist)
+	_, err = pm.Translate("file.go", 5)
+	if err == nil {
+		t.Error("expected error for position 5 (out of range)")
+	}
+
+	// Unknown file
+	_, err = pm.Translate("unknown.go", 1)
+	if err == nil {
+		t.Error("expected error for unknown file")
+	}
+}
+
+func TestBuildPositionToLineMap_MultipleFiles(t *testing.T) {
+	diff := `diff --git a/a.go b/a.go
+--- a/a.go
++++ b/a.go
+@@ -1,2 +1,3 @@
+ package a
++// file a
+ func aFunc() {}
+diff --git a/b.go b/b.go
+--- a/b.go
++++ b/b.go
+@@ -1,2 +1,3 @@
+ package b
++// file b
+ func bFunc() {}
+`
+	pm := BuildPositionToLineMap(diff)
+
+	// a.go: pos 3 is "+// file a" -> new line 2
+	got, err := pm.Translate("a.go", 3)
+	if err != nil {
+		t.Fatalf("Translate(a.go, 3): %v", err)
+	}
+	if got != 2 {
+		t.Errorf("Translate(a.go, 3) = %d, want 2", got)
+	}
+
+	// b.go: pos 3 is "+// file b" -> new line 2
+	// Note: position resets per file
+	got, err = pm.Translate("b.go", 3)
+	if err != nil {
+		t.Fatalf("Translate(b.go, 3): %v", err)
+	}
+	if got != 2 {
+		t.Errorf("Translate(b.go, 3) = %d, want 2", got)
+	}
+}
+
+func TestTranslate_HunkHeaderPosition_SingleHunk(t *testing.T) {
+	// Position 1 is the @@ hunk-header line.
+	// It should resolve to the first context/addition line below (new line 16).
+	diff := `diff --git a/file.go b/file.go
+index abc..def 100644
+--- a/file.go
++++ b/file.go
+@@ -16,4 +16,5 @@ func example() {
+ context line
+-deleted line
++added line
+ context after
+`
+	pm := BuildPositionToLineMap(diff)
+
+	got, err := pm.Translate("file.go", 1)
+	if err != nil {
+		t.Fatalf("Translate(file.go, 1): unexpected error: %v", err)
+	}
+	if got != 16 {
+		t.Errorf("Translate(file.go, 1) = %d, want 16 (first context/addition line in hunk)", got)
+	}
+}
+
+func TestTranslate_HunkHeaderPosition_MultiHunk(t *testing.T) {
+	// First hunk: @@ is pos 1, then " line1" (pos 2), "-old" (pos 3), "+new" (pos 4)
+	// Second hunk: @@ is pos 5, then " func foo() {" (pos 6), "+// added" (pos 7), etc.
+	// Translating position 5 (second @@) should resolve to new line 10.
+	diff := `diff --git a/file.go b/file.go
+--- a/file.go
++++ b/file.go
+@@ -1,3 +1,3 @@ package main
+ line1
+-old
++new
+@@ -10,3 +10,4 @@ func foo() {
+ func foo() {
++	// added
+ 	return
+ }
+`
+	pm := BuildPositionToLineMap(diff)
+
+	// Position 5 is the second @@ hunk-header — should resolve to new line 10
+	got, err := pm.Translate("file.go", 5)
+	if err != nil {
+		t.Fatalf("Translate(file.go, 5): unexpected error: %v", err)
+	}
+	if got != 10 {
+		t.Errorf("Translate(file.go, 5) = %d, want 10 (first context/addition line in second hunk)", got)
+	}
+
+	// Also verify first hunk header at position 1 resolves to new line 1
+	got, err = pm.Translate("file.go", 1)
+	if err != nil {
+		t.Fatalf("Translate(file.go, 1): unexpected error: %v", err)
+	}
+	if got != 1 {
+		t.Errorf("Translate(file.go, 1) = %d, want 1 (first context/addition line in first hunk)", got)
+	}
+}
+
+func TestTranslate_HunkHeaderPosition_NewFile(t *testing.T) {
+	// New file: @@ -0,0 +1,3 @@ is position 1.
+	// Should resolve to new line 1 (the first addition).
+	diff := `diff --git a/new.go b/new.go
+new file mode 100644
+--- /dev/null
++++ b/new.go
+@@ -0,0 +1,3 @@
++package main
++
++func init() {}
+`
+	pm := BuildPositionToLineMap(diff)
+
+	got, err := pm.Translate("new.go", 1)
+	if err != nil {
+		t.Fatalf("Translate(new.go, 1): unexpected error: %v", err)
+	}
+	if got != 1 {
+		t.Errorf("Translate(new.go, 1) = %d, want 1 (first addition line)", got)
+	}
+}
+
+func TestTranslate_HunkHeaderAtEnd(t *testing.T) {
+	// A hunk-header at the last position with no subsequent new-file line should error.
+	// This is the hunk-header equivalent of TestBuildPositionToLineMap_DeletionAtEnd.
+	diff := `diff --git a/file.go b/file.go
+--- a/file.go
++++ b/file.go
+@@ -1,2 +1,2 @@ package main
+ line1
+-old
++new
+@@ -10,2 +10,1 @@ func foo() {
+-removed
+`
+	pm := BuildPositionToLineMap(diff)
+
+	// Position 5 is the second @@ hunk-header; the only line after it (pos 6) is a
+	// deletion (lineNum == -1), so there's no positive new-file line to resolve to.
+	// The hunk-header lookup should fail.
+	_, err := pm.Translate("file.go", 5)
+	if err == nil {
+		t.Error("expected error for hunk-header at end with no subsequent new-file line")
+	}
+}

gitea/post_review_comments_test.go

@@ -0,0 +1,88 @@
+package gitea
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+)
+
+func TestPostReview_WithComments(t *testing.T) {
+	var gotPayload struct {
+		Body     string `json:"body"`
+		Event    string `json:"event"`
+		Comments []struct {
+			Path        string `json:"path"`
+			NewPosition int64  `json:"new_position"`
+			Body        string `json:"body"`
+		} `json:"comments"`
+	}
+
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		json.NewDecoder(r.Body).Decode(&gotPayload)
+		w.Header().Set("Content-Type", "application/json")
+		w.WriteHeader(200)
+		json.NewEncoder(w).Encode(map[string]any{
+			"id":   99,
+			"body": gotPayload.Body,
+			"user": map[string]any{"login": "bot"},
+		})
+	}))
+	defer server.Close()
+
+	client := NewClient(server.URL, "test-token")
+	comments := []ReviewComment{
+		{Path: "main.go", NewPosition: 42, Body: "[MAJOR] Something bad"},
+		{Path: "util.go", NewPosition: 10, Body: "[MINOR] Style issue"},
+	}
+
+	_, err := client.PostReview(context.Background(), "owner", "repo", 1, "REQUEST_CHANGES", "summary", "", comments)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	if len(gotPayload.Comments) != 2 {
+		t.Fatalf("expected 2 comments, got %d", len(gotPayload.Comments))
+	}
+	if gotPayload.Comments[0].Path != "main.go" {
+		t.Errorf("expected path main.go, got %s", gotPayload.Comments[0].Path)
+	}
+	if gotPayload.Comments[0].NewPosition != 42 {
+		t.Errorf("expected new_position 42, got %d", gotPayload.Comments[0].NewPosition)
+	}
+	if gotPayload.Comments[1].Body != "[MINOR] Style issue" {
+		t.Errorf("unexpected body: %s", gotPayload.Comments[1].Body)
+	}
+}
+
+func TestPostReview_NilComments(t *testing.T) {
+	var gotPayload map[string]any
+
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		json.NewDecoder(r.Body).Decode(&gotPayload)
+		w.Header().Set("Content-Type", "application/json")
+		w.WriteHeader(200)
+		json.NewEncoder(w).Encode(map[string]any{
+			"id":   100,
+			"body": "test",
+			"user": map[string]any{"login": "bot"},
+		})
+	}))
+	defer server.Close()
+
+	client := NewClient(server.URL, "test-token")
+	_, err := client.PostReview(context.Background(), "owner", "repo", 1, "APPROVED", "all good", "", nil)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	// With nil comments, the field should be omitted (omitempty)
+	comments, ok := gotPayload["comments"]
+	if ok && comments != nil {
+		arr, isArr := comments.([]any)
+		if isArr && len(arr) > 0 {
+			t.Error("expected no comments in payload when nil passed")
+		}
+	}
+}

gitea/supersede_test.go

@@ -0,0 +1,54 @@
+package gitea
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestBuildSupersededBody(t *testing.T) {
+	original := "# Review\n\nLooks good.\n\n<!-- review-bot:sonnet -->"
+	sentinel := "<!-- review-bot:sonnet -->"
+	newURL := "https://gitea.example.com/owner/repo/pulls/1#pullrequestreview-99"
+
+	result := buildSupersededBody(original, "abcdef1234567890", newURL, sentinel)
+
+	// Should contain the struck-through banner
+	if !strings.Contains(result, "~~Original review~~") {
+		t.Error("missing struck-through banner")
+	}
+	// Should contain superseded notice with link
+	if !strings.Contains(result, "**Superseded**") {
+		t.Error("missing superseded notice")
+	}
+	if !strings.Contains(result, "[see current review]("+newURL+")") {
+		t.Error("missing link to new review")
+	}
+	// Should contain collapsed original
+	if !strings.Contains(result, "<details>") {
+		t.Error("missing details/collapse")
+	}
+	// Should contain short commit SHA
+	if !strings.Contains(result, "abcdef12") {
+		t.Error("missing short SHA")
+	}
+	// Should NOT contain full SHA in summary (it's truncated to 8)
+	if strings.Contains(result, "abcdef1234567890") {
+		t.Error("should truncate SHA to 8 chars")
+	}
+	// Should contain the original body inside details
+	if !strings.Contains(result, original) {
+		t.Error("original body not preserved in collapsed section")
+	}
+	// Should end with sentinel
+	if !strings.Contains(result, sentinel) {
+		t.Error("missing sentinel")
+	}
+}
+
+func TestBuildSupersededBodyShortSHA(t *testing.T) {
+	// Short SHA should pass through without panic
+	result := buildSupersededBody("body", "abc", "https://example.com/review", "<!-- review-bot:x -->")
+	if !strings.Contains(result, "abc") {
+		t.Error("short SHA not preserved")
+	}
+}

github/client.go

@@ -0,0 +1,411 @@
+// Package github provides a client for the GitHub API.
+// It supports pull request operations, file content retrieval, CI status checks,
+// and directory listing for both github.com and GitHub Enterprise.
+package github
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"strconv"
+	"strings"
+	"time"
+)
+
+const (
+	defaultBaseURL = "https://api.github.com"
+	userAgent      = "review-bot/1.0"
+
+	// maxResponseBytes limits successful response body reads to 10 MiB.
+	maxResponseBytes = 10 * 1024 * 1024
+
+	// maxRetryAttempts is the number of times doRequest will attempt a request.
+	// The retry backoff slice must have length maxRetryAttempts-1.
+	maxRetryAttempts = 3
+)
+
+// APIError represents an HTTP error response from the GitHub API.
+// It carries the status code so callers can distinguish between
+// different failure modes (e.g. 404 vs 500).
+//
+// The Body field stores up to 4 KiB of the raw response for programmatic
+// inspection. Error() truncates to 200 bytes for safe logging, but callers
+// should avoid logging or propagating Body directly in production since it may
+// contain sensitive details from the upstream server.
+type APIError struct {
+	StatusCode int
+	Body       string
+}
+
+func (e *APIError) Error() string {
+	body := e.Body
+	if len(body) > 200 {
+		body = body[:200] + "...(truncated)"
+	}
+	// Sanitize newlines to prevent log injection from upstream response bodies.
+	body = strings.ReplaceAll(body, "\n", " ")
+	body = strings.ReplaceAll(body, "\r", " ")
+	return fmt.Sprintf("HTTP %d: %s", e.StatusCode, body)
+}
+
+// IsNotFound reports whether an error is an API 404 response.
+func IsNotFound(err error) bool {
+	if apiErr, ok := asAPIError(err); ok {
+		return apiErr.StatusCode == http.StatusNotFound
+	}
+	return false
+}
+
+// IsUnauthorized reports whether an error is an API 401 response.
+func IsUnauthorized(err error) bool {
+	if apiErr, ok := asAPIError(err); ok {
+		return apiErr.StatusCode == http.StatusUnauthorized
+	}
+	return false
+}
+
+func asAPIError(err error) (*APIError, bool) {
+	if err == nil {
+		return nil, false
+	}
+	var target *APIError
+	if errors.As(err, &target) {
+		return target, true
+	}
+	return nil, false
+}
+
+// clientConfig holds optional configuration for NewClient.
+type clientConfig struct {
+	allowInsecureHTTP bool
+}
+
+// ClientOption configures optional behavior of NewClient.
+type ClientOption func(*clientConfig)
+
+// AllowInsecureHTTP permits the client to use HTTP (non-TLS) base URLs.
+// This should only be used for trusted internal deployments or testing.
+func AllowInsecureHTTP() ClientOption {
+	return func(c *clientConfig) {
+		c.allowInsecureHTTP = true
+	}
+}
+
+// Client interacts with the GitHub API.
+// A Client is safe for concurrent use by multiple goroutines.
+// SetHTTPClient and SetRetryBackoff are intended for test setup only and must
+// be called before any goroutines issue requests; they have no synchronization.
+type Client struct {
+	baseURL           string
+	token             string
+	allowInsecureHTTP bool
+	httpClient        *http.Client
+
+	// retryBackoff defines the delays between retry attempts for 429 responses.
+	// retryBackoff[i] is the delay before attempt i+1 (after attempt i fails).
+	// If nil, defaults to {1s, 2s}. Set to shorter durations in tests via SetRetryBackoff.
+	retryBackoff []time.Duration
+
+	// reviewPageSize overrides reviewsPerPage for testing. Zero means use default.
+	reviewPageSize int
+	// reviewMaxPages overrides maxReviewPages for testing. Zero means use default.
+	reviewMaxPages int
+}
+
+// defaultCheckRedirect is the redirect policy used by NewClient and SetHTTPClient(nil).
+// It rejects HTTPS→HTTP protocol downgrades (to prevent plaintext leakage) and strips
+// the Authorization header on cross-host redirects to prevent credential leakage to
+// third-party hosts (e.g. CDN redirects from GitHub).
+func defaultCheckRedirect(req *http.Request, via []*http.Request) error {
+	if len(via) >= 10 {
+		return fmt.Errorf("stopped after 10 redirects")
+	}
+	// Guard: net/http guarantees len(via) >= 1 but this is undocumented;
+	// defend against zero-length to avoid panic on index out of range.
+	if len(via) == 0 {
+		return nil
+	}
+	prev := via[len(via)-1]
+	// Reject protocol downgrade: HTTPS→HTTP leaks request metadata over plaintext.
+	if prev.URL.Scheme == "https" && req.URL.Scheme == "http" {
+		return fmt.Errorf("refusing redirect from HTTPS to HTTP (%s → %s)", prev.URL.Host, req.URL.Host)
+	}
+	// Strip Authorization on cross-host redirect to avoid leaking credentials
+	// to third-party hosts (GitHub legitimately redirects to CDN hosts).
+	if req.URL.Host != prev.URL.Host {
+		req.Header.Del("Authorization")
+	}
+	return nil
+}
+
+// NewClient creates a new GitHub API client.
+// If baseURL is empty, it defaults to https://api.github.com.
+// For GitHub Enterprise, pass the API base URL (e.g. https://github.concur.com/api/v3).
+// The baseURL must use HTTPS; pass AllowInsecureHTTP() as an option to permit HTTP
+// for trusted internal deployments (e.g. local testing).
+func NewClient(token, baseURL string, opts ...ClientOption) *Client {
+	if baseURL == "" {
+		baseURL = defaultBaseURL
+	}
+	cfg := clientConfig{}
+	for _, o := range opts {
+		o(&cfg)
+	}
+	return &Client{
+		baseURL:           strings.TrimRight(baseURL, "/"),
+		allowInsecureHTTP: cfg.allowInsecureHTTP,
+		token:             token,
+		httpClient: &http.Client{
+			Timeout:       30 * time.Second,
+			CheckRedirect: defaultCheckRedirect,
+		},
+	}
+}
+
+// SetHTTPClient sets the underlying HTTP client used for requests.
+// This is intended for test setup only to inject mock transports; it must be
+// called before any goroutines issue requests.
+//
+// Passing nil restores the default client (30s timeout + auth-stripping
+// CheckRedirect policy matching NewClient).
+//
+// Callers providing a non-nil client are responsible for configuring a safe
+// CheckRedirect policy. Without one, the default net/http behavior will follow
+// redirects and may forward the Authorization header to untrusted hosts.
+func (c *Client) SetHTTPClient(hc *http.Client) {
+	if hc == nil {
+		hc = &http.Client{
+			Timeout:       30 * time.Second,
+			CheckRedirect: defaultCheckRedirect,
+		}
+	}
+	c.httpClient = hc
+}
+
+// SetRetryBackoff configures the retry backoff durations for testing.
+// It must be called before any goroutines issue requests.
+// The slice must have exactly maxRetryAttempts-1 entries (one delay per retry gap).
+// In production the default {1s, 2s} applies.
+func (c *Client) SetRetryBackoff(d []time.Duration) error {
+	if len(d) != maxRetryAttempts-1 {
+		return fmt.Errorf("github: backoff length %d does not match maxRetryAttempts-1 (%d)", len(d), maxRetryAttempts-1)
+	}
+	c.retryBackoff = d
+	return nil
+}
+
+// SetReviewPagination overrides the page size and max pages for ListReviews.
+// Intended for testing only; must be called before any goroutines issue requests.
+func (c *Client) SetReviewPagination(pageSize, maxPages int) {
+	c.reviewPageSize = pageSize
+	c.reviewMaxPages = maxPages
+}
+
+// requestOptions holds per-request configuration for doRequestCore.
+type requestOptions struct {
+	// bodyFn returns a fresh io.Reader for the request body on each attempt.
+	// Must be non-nil for any request that carries a body (POST, PUT, PATCH,
+	// or DELETE when a body is required by the API).
+	// Returning a fresh reader on each call allows retries to re-send the body.
+	bodyFn func() io.Reader
+
+	// accept overrides the default Accept header. Empty means "application/vnd.github+json".
+	accept string
+
+	// extraHeaders are additional headers to set on each request attempt.
+	extraHeaders map[string]string
+}
+
+// doRequestCore is the shared implementation for all HTTP requests with retry
+// on 429 rate limit responses. It respects the Retry-After header when present
+// (capped at maxRetryAfter). Transport errors are not retried.
+func (c *Client) doRequestCore(ctx context.Context, method, reqURL string, opts requestOptions) ([]byte, error) {
+	const maxRetryAfter = 120 * time.Second
+
+	// maxErrorBodyBytes limits how much of an error response body is stored.
+	// Kept small (4 KiB) to reduce the risk of sensitive data leakage if callers
+	// log APIError.Body directly. Error() further truncates to 200 bytes.
+	const maxErrorBodyBytes = 4 * 1024
+
+	// backoff holds per-attempt delays: backoff[i] is the delay before attempt i+1.
+	// Length must be maxRetryAttempts-1 (one entry per retry gap).
+	// SetRetryBackoff validates at configuration time; the default is always valid.
+	defaultBackoff := []time.Duration{1 * time.Second, 2 * time.Second}
+	var backoff []time.Duration
+	if c.retryBackoff != nil && len(c.retryBackoff) == maxRetryAttempts-1 {
+		backoff = make([]time.Duration, len(c.retryBackoff))
+		copy(backoff, c.retryBackoff)
+	} else {
+		backoff = make([]time.Duration, len(defaultBackoff))
+		copy(backoff, defaultBackoff)
+	}
+
+	// Reject non-HTTPS URLs early since the URL is immutable across retries.
+	if c.token != "" && !c.allowInsecureHTTP {
+		parsed, err := url.Parse(reqURL)
+		if err != nil {
+			return nil, fmt.Errorf("parse request URL: %w", err)
+		}
+		if !strings.EqualFold(parsed.Scheme, "https") {
+			return nil, fmt.Errorf("refusing to send credentials over non-HTTPS URL %q (use AllowInsecureHTTP option for trusted networks)", reqURL)
+		}
+	}
+
+	var lastErr error
+	for attempt := 0; attempt < maxRetryAttempts; attempt++ {
+		if attempt > 0 {
+			var delay time.Duration
+			if attempt-1 < len(backoff) {
+				delay = backoff[attempt-1]
+			}
+			if delay > 0 {
+				timer := time.NewTimer(delay)
+				select {
+				case <-timer.C:
+					timer.Stop() // no-op after fire; kept for symmetry with the ctx.Done case
+				case <-ctx.Done():
+					timer.Stop()
+					return nil, ctx.Err()
+				}
+			}
+		}
+
+		var body io.Reader
+		if opts.bodyFn != nil {
+			body = opts.bodyFn()
+		}
+		req, err := http.NewRequestWithContext(ctx, method, reqURL, body)
+		if err != nil {
+			return nil, fmt.Errorf("create request: %w", err)
+		}
+		if c.token != "" {
+			// Bearer is the OAuth2 standard and is accepted by GitHub for both
+			// classic PATs and fine-grained tokens. The alternative "token" scheme
+			// is GitHub-specific and offers no additional compatibility.
+			req.Header.Set("Authorization", "Bearer "+c.token)
+		}
+		req.Header.Set("User-Agent", userAgent)
+		if opts.accept != "" {
+			req.Header.Set("Accept", opts.accept)
+		} else {
+			req.Header.Set("Accept", "application/vnd.github+json")
+		}
+		for k, v := range opts.extraHeaders {
+			req.Header.Set(k, v)
+		}
+
+		resp, err := c.httpClient.Do(req)
+		if err != nil {
+			return nil, fmt.Errorf("do request: %w", err)
+		}
+
+		// Capture response metadata before handleResponse takes body ownership.
+		respStatus := resp.StatusCode
+		retryAfterHeader := resp.Header.Get("Retry-After")
+
+		respBody, done, handleErr := c.handleResponse(resp, maxResponseBytes, maxErrorBodyBytes)
+		if done {
+			return respBody, handleErr
+		}
+		lastErr = handleErr
+
+		// Retry on 429 rate limit
+		if respStatus == http.StatusTooManyRequests && attempt < maxRetryAttempts-1 {
+			// Check for Retry-After header and override backoff if present.
+			// Supports both integer seconds (common) and HTTP-date format (RFC 7231).
+			if ra := retryAfterHeader; ra != "" {
+				if seconds, err := strconv.Atoi(ra); err == nil && seconds > 0 {
+					delay := time.Duration(seconds) * time.Second
+					if delay > maxRetryAfter {
+						delay = maxRetryAfter
+					}
+					if attempt < len(backoff) {
+						backoff[attempt] = delay
+					}
+				} else if retryAt, err := http.ParseTime(ra); err == nil {
+					delay := time.Until(retryAt)
+					if delay < 0 {
+						delay = 0
+					}
+					if delay > maxRetryAfter {
+						delay = maxRetryAfter
+					}
+					if attempt < len(backoff) {
+						backoff[attempt] = delay
+					}
+				}
+			}
+			continue
+		}
+
+		// Don't retry other errors
+		return nil, lastErr
+	}
+
+	return nil, lastErr
+}
+
+// doRequest performs an HTTP request with retry on 429 rate limit responses.
+// It respects the Retry-After header when present (capped at maxRetryAfter).
+// Transport errors (network failures, context cancellation) are not retried.
+func (c *Client) doRequest(ctx context.Context, method, reqURL string, accept string) ([]byte, error) {
+	return c.doRequestCore(ctx, method, reqURL, requestOptions{accept: accept})
+}
+
+// handleResponse reads and closes the response body, returning the result.
+// It uses defer to ensure the body is always closed regardless of code path.
+// Returns (body, done, err) where done=true means the caller should return immediately.
+func (c *Client) handleResponse(resp *http.Response, maxRespBytes int, maxErrBytes int) ([]byte, bool, error) {
+	defer resp.Body.Close()
+
+	if resp.StatusCode >= 200 && resp.StatusCode < 300 {
+		body, err := io.ReadAll(io.LimitReader(resp.Body, int64(maxRespBytes)+1))
+		if err != nil {
+			return nil, true, fmt.Errorf("read response body: %w", err)
+		}
+		if len(body) > maxRespBytes {
+			return nil, true, fmt.Errorf("response body exceeded %d bytes", maxRespBytes)
+		}
+		return body, true, nil
+	}
+
+	errBody, readErr := io.ReadAll(io.LimitReader(resp.Body, int64(maxErrBytes)))
+	if readErr != nil && len(errBody) == 0 {
+		errBody = []byte(fmt.Sprintf("[error reading response body: %v]", readErr))
+	}
+	return nil, false, &APIError{StatusCode: resp.StatusCode, Body: string(errBody)}
+}
+
+// doGet is a convenience wrapper for GET requests with the default Accept header.
+func (c *Client) doGet(ctx context.Context, reqURL string) ([]byte, error) {
+	return c.doRequest(ctx, http.MethodGet, reqURL, "")
+}
+
+// doRequestWithBody is like doRequest but sends a request body.
+// It accepts the raw body bytes and sets Content-Type to application/json.
+// Retry semantics match doRequest (retries on 429 with Retry-After support).
+func (c *Client) doRequestWithBody(ctx context.Context, method, reqURL string, reqBody []byte) ([]byte, error) {
+	var opts requestOptions
+	if reqBody != nil {
+		opts.bodyFn = func() io.Reader { return bytes.NewReader(reqBody) }
+		opts.extraHeaders = map[string]string{"Content-Type": "application/json"}
+	}
+	return c.doRequestCore(ctx, method, reqURL, opts)
+}
+
+// doJSONRequest performs an HTTP request with a JSON body and returns the response body.
+// It delegates retry/backoff/429 handling to doRequestWithBody.
+// This is a general-purpose helper used by any method that needs to send JSON payloads
+// (e.g. PostReview, DismissReview).
+func (c *Client) doJSONRequest(ctx context.Context, method, reqURL string, payload any) ([]byte, error) {
+	jsonBody, err := json.Marshal(payload)
+	if err != nil {
+		return nil, fmt.Errorf("marshal request body: %w", err)
+	}
+	return c.doRequestWithBody(ctx, method, reqURL, jsonBody)
+}

github/client_test.go

@@ -0,0 +1,650 @@
+package github
+
+import (
+	"context"
+	"errors"
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"strings"
+	"testing"
+	"time"
+)
+
+func TestNewClient_DefaultBaseURL(t *testing.T) {
+	c := NewClient("test-token", "")
+	if c.baseURL != "https://api.github.com" {
+		t.Errorf("expected default base URL, got %q", c.baseURL)
+	}
+}
+
+func TestNewClient_CustomBaseURL(t *testing.T) {
+	c := NewClient("test-token", "https://github.concur.com/api/v3")
+	if c.baseURL != "https://github.concur.com/api/v3" {
+		t.Errorf("expected custom base URL, got %q", c.baseURL)
+	}
+}
+
+func TestNewClient_TrimsTrailingSlash(t *testing.T) {
+	c := NewClient("test-token", "https://github.concur.com/api/v3/")
+	if c.baseURL != "https://github.concur.com/api/v3" {
+		t.Errorf("expected trailing slash trimmed, got %q", c.baseURL)
+	}
+}
+
+func TestDoRequest_SetsAuthHeader(t *testing.T) {
+	var gotAuth string
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		gotAuth = r.Header.Get("Authorization")
+		w.WriteHeader(200)
+		w.Write([]byte("{}"))
+	}))
+	defer srv.Close()
+
+	c := NewClient("my-token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+	_, _ = c.doGet(context.Background(), srv.URL+"/test")
+
+	if gotAuth != "Bearer my-token" {
+		t.Errorf("expected Bearer auth, got %q", gotAuth)
+	}
+}
+
+func TestDoRequest_SetsDefaultAcceptHeader(t *testing.T) {
+	var gotAccept string
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		gotAccept = r.Header.Get("Accept")
+		w.WriteHeader(200)
+		w.Write([]byte("{}"))
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+	_, _ = c.doGet(context.Background(), srv.URL+"/test")
+
+	if gotAccept != "application/vnd.github+json" {
+		t.Errorf("expected default Accept header, got %q", gotAccept)
+	}
+}
+
+func TestDoRequest_429Retry(t *testing.T) {
+	attempts := 0
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		attempts++
+		if attempts == 1 {
+			w.WriteHeader(429)
+			w.Write([]byte(`{"message":"rate limit"}`))
+			return
+		}
+		w.WriteHeader(200)
+		w.Write([]byte(`{"ok":true}`))
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+	if err := c.SetRetryBackoff([]time.Duration{10 * time.Millisecond, 10 * time.Millisecond}); err != nil {
+		t.Fatalf("SetRetryBackoff: %v", err)
+	}
+
+	body, err := c.doGet(context.Background(), srv.URL+"/test")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if string(body) != `{"ok":true}` {
+		t.Errorf("unexpected body: %s", body)
+	}
+	if attempts != 2 {
+		t.Errorf("expected 2 attempts, got %d", attempts)
+	}
+}
+
+func TestDoRequest_429ExhaustsRetries(t *testing.T) {
+	attempts := 0
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		attempts++
+		w.WriteHeader(429)
+		w.Write([]byte(`{"message":"rate limit"}`))
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+	if err := c.SetRetryBackoff([]time.Duration{1 * time.Millisecond, 1 * time.Millisecond}); err != nil {
+		t.Fatalf("SetRetryBackoff: %v", err)
+	}
+
+	_, err := c.doGet(context.Background(), srv.URL+"/test")
+	if err == nil {
+		t.Fatal("expected error after exhausting retries")
+	}
+	apiErr, ok := err.(*APIError)
+	if !ok {
+		t.Fatalf("expected *APIError, got %T", err)
+	}
+	if apiErr.StatusCode != 429 {
+		t.Errorf("expected 429, got %d", apiErr.StatusCode)
+	}
+	if attempts != 3 {
+		t.Errorf("expected 3 attempts, got %d", attempts)
+	}
+}
+
+func TestDoRequest_404NoRetry(t *testing.T) {
+	attempts := 0
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		attempts++
+		w.WriteHeader(404)
+		w.Write([]byte(`{"message":"not found"}`))
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+
+	_, err := c.doGet(context.Background(), srv.URL+"/test")
+	if err == nil {
+		t.Fatal("expected error for 404")
+	}
+	if attempts != 1 {
+		t.Errorf("expected 1 attempt (no retry on 404), got %d", attempts)
+	}
+}
+
+func TestDoRequest_401NoRetry(t *testing.T) {
+	attempts := 0
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		attempts++
+		w.WriteHeader(401)
+		w.Write([]byte(`{"message":"bad credentials"}`))
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+
+	_, err := c.doGet(context.Background(), srv.URL+"/test")
+	if err == nil {
+		t.Fatal("expected error for 401")
+	}
+	if attempts != 1 {
+		t.Errorf("expected 1 attempt (no retry on 401), got %d", attempts)
+	}
+}
+
+func TestIsNotFound(t *testing.T) {
+	err := &APIError{StatusCode: 404, Body: "not found"}
+	if !IsNotFound(err) {
+		t.Error("expected IsNotFound to return true for 404")
+	}
+	err2 := &APIError{StatusCode: 500, Body: "server error"}
+	if IsNotFound(err2) {
+		t.Error("expected IsNotFound to return false for 500")
+	}
+}
+
+func TestIsUnauthorized(t *testing.T) {
+	err := &APIError{StatusCode: 401, Body: "bad credentials"}
+	if !IsUnauthorized(err) {
+		t.Error("expected IsUnauthorized to return true for 401")
+	}
+}
+
+func TestAPIError_SanitizesNewlines(t *testing.T) {
+	err := &APIError{StatusCode: 500, Body: "line1\ninjected\rmore"}
+	msg := err.Error()
+	if strings.Contains(msg, "\n") || strings.Contains(msg, "\r") {
+		t.Errorf("expected newlines to be sanitized, got: %q", msg)
+	}
+	if !strings.Contains(msg, "line1 injected more") {
+		t.Errorf("expected sanitized body, got: %q", msg)
+	}
+}
+
+func TestDoRequest_429RetryAfterHeader(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping slow retry test in short mode")
+	}
+	attempts := 0
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		attempts++
+		if attempts == 1 {
+			w.Header().Set("Retry-After", "1")
+			w.WriteHeader(429)
+			w.Write([]byte(`{"message":"rate limit"}`))
+			return
+		}
+		w.WriteHeader(200)
+		w.Write([]byte(`{"ok":true}`))
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+	// Use short backoff; Retry-After should override
+	if err := c.SetRetryBackoff([]time.Duration{1 * time.Millisecond, 1 * time.Millisecond}); err != nil {
+		t.Fatalf("SetRetryBackoff: %v", err)
+	}
+
+	start := time.Now()
+	body, err := c.doGet(context.Background(), srv.URL+"/test")
+	elapsed := time.Since(start)
+
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if string(body) != `{"ok":true}` {
+		t.Errorf("unexpected body: %s", body)
+	}
+	if attempts != 2 {
+		t.Errorf("expected 2 attempts, got %d", attempts)
+	}
+	// Retry-After: 1 means at least 1 second delay
+	if elapsed < 900*time.Millisecond {
+		t.Errorf("expected ~1s delay from Retry-After, got %v", elapsed)
+	}
+}
+
+func TestDoRequest_RetryAfterDoesNotMutateBackoff(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping slow retry test in short mode")
+	}
+	attempts := 0
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		attempts++
+		if attempts == 1 {
+			w.Header().Set("Retry-After", "1")
+			w.WriteHeader(429)
+			w.Write([]byte(`{"message":"rate limit"}`))
+			return
+		}
+		w.WriteHeader(200)
+		w.Write([]byte(`{"ok":true}`))
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+	if err := c.SetRetryBackoff([]time.Duration{1 * time.Millisecond, 1 * time.Millisecond}); err != nil {
+		t.Fatalf("SetRetryBackoff: %v", err)
+	}
+
+	_, err := c.doGet(context.Background(), srv.URL+"/test")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	// Verify the original retryBackoff slice was not mutated
+	if c.retryBackoff[0] != 1*time.Millisecond {
+		t.Errorf("retryBackoff[0] was mutated: got %v, want 1ms", c.retryBackoff[0])
+	}
+	if c.retryBackoff[1] != 1*time.Millisecond {
+		t.Errorf("retryBackoff[1] was mutated: got %v, want 1ms", c.retryBackoff[1])
+	}
+}
+
+func TestDoRequest_429RetryAfterHTTPDate(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping slow Retry-After HTTP-date test in short mode")
+	}
+	attempts := 0
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		attempts++
+		if attempts == 1 {
+			// Use HTTP-date format (RFC 7231) — a time 2 seconds in the future.
+			future := time.Now().Add(2 * time.Second).UTC()
+			w.Header().Set("Retry-After", future.Format(http.TimeFormat))
+			w.WriteHeader(429)
+			w.Write([]byte(`{"message":"rate limit"}`))
+			return
+		}
+		w.WriteHeader(200)
+		w.Write([]byte(`{"ok":true}`))
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+	if err := c.SetRetryBackoff([]time.Duration{1 * time.Millisecond, 1 * time.Millisecond}); err != nil {
+		t.Fatalf("SetRetryBackoff: %v", err)
+	}
+
+	start := time.Now()
+	body, err := c.doGet(context.Background(), srv.URL+"/test")
+	elapsed := time.Since(start)
+
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if string(body) != `{"ok":true}` {
+		t.Errorf("unexpected body: %s", body)
+	}
+	if attempts != 2 {
+		t.Errorf("expected 2 attempts, got %d", attempts)
+	}
+	// HTTP-date was ~2s in the future; by the time client processes it,
+	// time.Until gives ~1-2s. Verify it's meaningfully delayed (not instant).
+	if elapsed < 500*time.Millisecond {
+		t.Errorf("expected meaningful delay from HTTP-date Retry-After, got %v", elapsed)
+	}
+}
+
+func TestDoRequest_429RetryAfterHTTPDateInPast(t *testing.T) {
+	attempts := 0
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		attempts++
+		if attempts == 1 {
+			// Use a time in the past — should result in zero/immediate retry.
+			past := time.Now().Add(-10 * time.Second).UTC()
+			w.Header().Set("Retry-After", past.Format(http.TimeFormat))
+			w.WriteHeader(429)
+			w.Write([]byte(`{"message":"rate limit"}`))
+			return
+		}
+		w.WriteHeader(200)
+		w.Write([]byte(`{"ok":true}`))
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+	if err := c.SetRetryBackoff([]time.Duration{5 * time.Second, 5 * time.Second}); err != nil {
+		t.Fatalf("SetRetryBackoff: %v", err)
+	}
+
+	start := time.Now()
+	_, err := c.doGet(context.Background(), srv.URL+"/test")
+	elapsed := time.Since(start)
+
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if attempts != 2 {
+		t.Errorf("expected 2 attempts, got %d", attempts)
+	}
+	// Past date should override the 5s backoff to ~0
+	if elapsed > 500*time.Millisecond {
+		t.Errorf("expected near-instant retry for past HTTP-date, got %v", elapsed)
+	}
+}
+
+func TestDoRequest_SetsUserAgentHeader(t *testing.T) {
+	var gotUA string
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		gotUA = r.Header.Get("User-Agent")
+		w.WriteHeader(200)
+		w.Write([]byte("{}"))
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+	_, _ = c.doGet(context.Background(), srv.URL+"/test")
+
+	if gotUA != "review-bot/1.0" {
+		t.Errorf("expected User-Agent 'review-bot/1.0', got %q", gotUA)
+	}
+}
+
+func TestDoRequest_LimitsResponseBody(t *testing.T) {
+	// Verify that oversized responses return an error rather than silently truncating.
+	bigBody := strings.Repeat("x", maxResponseBytes+1024)
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(200)
+		w.Write([]byte(bigBody))
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+	_, err := c.doGet(context.Background(), srv.URL+"/test")
+	if err == nil {
+		t.Fatal("expected error for oversized response body")
+	}
+	if !strings.Contains(err.Error(), "exceeded") {
+		t.Errorf("expected truncation error, got: %v", err)
+	}
+}
+
+func TestDoRequest_AcceptsExactlyAtLimit(t *testing.T) {
+	// A response body exactly equal to maxResponseBytes should succeed (not error).
+	exactBody := strings.Repeat("x", maxResponseBytes)
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(200)
+		w.Write([]byte(exactBody))
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+	body, err := c.doGet(context.Background(), srv.URL+"/test")
+	if err != nil {
+		t.Fatalf("unexpected error for exactly-at-limit body: %v", err)
+	}
+	if len(body) != maxResponseBytes {
+		t.Errorf("expected body length %d, got %d", maxResponseBytes, len(body))
+	}
+}
+
+func TestDoRequest_SkipsAuthWhenTokenEmpty(t *testing.T) {
+	var gotAuth string
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		gotAuth = r.Header.Get("Authorization")
+		w.WriteHeader(200)
+		w.Write([]byte("{}"))
+	}))
+	defer srv.Close()
+
+	c := NewClient("", srv.URL, AllowInsecureHTTP()) // empty token
+	c.SetHTTPClient(srv.Client())
+	_, _ = c.doGet(context.Background(), srv.URL+"/test")
+
+	if gotAuth != "" {
+		t.Errorf("expected no Authorization header with empty token, got %q", gotAuth)
+	}
+}
+
+func TestNewClient_CheckRedirectStripsAuthOnCrossHost(t *testing.T) {
+	// Verify the CheckRedirect function is configured
+	c := NewClient("secret-token", "https://api.github.com")
+	if c.httpClient.CheckRedirect == nil {
+		t.Fatal("expected CheckRedirect to be set")
+	}
+}
+
+func TestDefaultCheckRedirect_RejectsHTTPSToHTTP(t *testing.T) {
+	prev := &http.Request{URL: &url.URL{Scheme: "https", Host: "api.github.com", Path: "/foo"}}
+	req := &http.Request{
+		URL:    &url.URL{Scheme: "http", Host: "api.github.com", Path: "/foo"},
+		Header: http.Header{"Authorization": []string{"Bearer token"}},
+	}
+	err := defaultCheckRedirect(req, []*http.Request{prev})
+	if err == nil {
+		t.Fatal("expected error on HTTPS→HTTP redirect")
+	}
+	if !strings.Contains(err.Error(), "refusing redirect from HTTPS to HTTP") {
+		t.Errorf("unexpected error message: %v", err)
+	}
+}
+
+func TestDefaultCheckRedirect_StripsAuthOnCrossHost(t *testing.T) {
+	prev := &http.Request{URL: &url.URL{Scheme: "https", Host: "api.github.com", Path: "/foo"}}
+	req := &http.Request{
+		URL:    &url.URL{Scheme: "https", Host: "objects.githubusercontent.com", Path: "/bar"},
+		Header: http.Header{"Authorization": []string{"Bearer token"}},
+	}
+	err := defaultCheckRedirect(req, []*http.Request{prev})
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if auth := req.Header.Get("Authorization"); auth != "" {
+		t.Errorf("expected Authorization header to be stripped, got %q", auth)
+	}
+}
+
+func TestDefaultCheckRedirect_PreservesAuthOnSameHost(t *testing.T) {
+	prev := &http.Request{URL: &url.URL{Scheme: "https", Host: "api.github.com", Path: "/foo"}}
+	req := &http.Request{
+		URL:    &url.URL{Scheme: "https", Host: "api.github.com", Path: "/bar"},
+		Header: http.Header{"Authorization": []string{"Bearer token"}},
+	}
+	err := defaultCheckRedirect(req, []*http.Request{prev})
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if auth := req.Header.Get("Authorization"); auth != "Bearer token" {
+		t.Errorf("expected Authorization to be preserved, got %q", auth)
+	}
+}
+
+func TestDoRequest_RejectsHTTPWithToken(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(200)
+		w.Write([]byte("{}"))
+	}))
+	defer srv.Close()
+
+	// Without AllowInsecureHTTP, should refuse to send token over HTTP
+	c := NewClient("secret-token", srv.URL)
+	c.SetHTTPClient(srv.Client())
+	_, err := c.doGet(context.Background(), srv.URL+"/test")
+	if err == nil {
+		t.Fatal("expected error when sending token over HTTP")
+	}
+	if !strings.Contains(err.Error(), "refusing to send credentials") {
+		t.Errorf("unexpected error message: %v", err)
+	}
+}
+
+func TestDoRequest_AllowsHTTPWithoutToken(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(200)
+		w.Write([]byte(`{"ok":true}`))
+	}))
+	defer srv.Close()
+
+	// Without token, HTTP should be fine (no credentials to leak)
+	c := NewClient("", srv.URL)
+	c.SetHTTPClient(srv.Client())
+	body, err := c.doGet(context.Background(), srv.URL+"/test")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if string(body) != `{"ok":true}` {
+		t.Errorf("unexpected body: %s", body)
+	}
+}
+
+func TestDoRequest_AllowsHTTPWithInsecureOption(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(200)
+		w.Write([]byte(`{"ok":true}`))
+	}))
+	defer srv.Close()
+
+	c := NewClient("secret-token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+	body, err := c.doGet(context.Background(), srv.URL+"/test")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if string(body) != `{"ok":true}` {
+		t.Errorf("unexpected body: %s", body)
+	}
+}
+
+func TestSetHTTPClient_NilRestoresDefault(t *testing.T) {
+	c := NewClient("token", "https://api.github.com")
+	c.SetHTTPClient(nil)
+	if c.httpClient == nil {
+		t.Fatal("expected non-nil httpClient after SetHTTPClient(nil)")
+	}
+	if c.httpClient.Timeout != 30*time.Second {
+		t.Errorf("expected 30s timeout, got %v", c.httpClient.Timeout)
+	}
+	if c.httpClient.CheckRedirect == nil {
+		t.Fatal("expected CheckRedirect policy after SetHTTPClient(nil)")
+	}
+}
+
+func TestSetRetryBackoff_RejectsInvalidLength(t *testing.T) {
+	c := NewClient("token", "https://api.github.com")
+
+	// Too short
+	err := c.SetRetryBackoff([]time.Duration{1 * time.Second})
+	if err == nil {
+		t.Fatal("expected error for backoff length 1")
+	}
+	if !strings.Contains(err.Error(), "backoff length 1") {
+		t.Errorf("unexpected error message: %v", err)
+	}
+
+	// Too long
+	err = c.SetRetryBackoff([]time.Duration{1 * time.Second, 2 * time.Second, 3 * time.Second})
+	if err == nil {
+		t.Fatal("expected error for backoff length 3")
+	}
+
+	// Correct length succeeds
+	err = c.SetRetryBackoff([]time.Duration{1 * time.Second, 2 * time.Second})
+	if err != nil {
+		t.Fatalf("unexpected error for valid backoff: %v", err)
+	}
+}
+
+func TestDoJSONRequest_429Retry(t *testing.T) {
+	attempts := 0
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		attempts++
+		if attempts < 3 {
+			w.WriteHeader(429)
+			w.Write([]byte(`{"message":"rate limit exceeded"}`))
+			return
+		}
+		w.WriteHeader(200)
+		w.Write([]byte(`{"id":1}`))
+	}))
+	defer ts.Close()
+
+	c := NewClient("token", ts.URL, AllowInsecureHTTP())
+	if err := c.SetRetryBackoff([]time.Duration{1 * time.Millisecond, 1 * time.Millisecond}); err != nil {
+		t.Fatalf("SetRetryBackoff: %v", err)
+	}
+
+	body, err := c.doJSONRequest(context.Background(), http.MethodPost, ts.URL+"/test", map[string]string{"key": "val"})
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if attempts != 3 {
+		t.Errorf("expected 3 attempts, got %d", attempts)
+	}
+	if string(body) != `{"id":1}` {
+		t.Errorf("unexpected body: %s", body)
+	}
+}
+
+func TestDoJSONRequest_429ExhaustsRetries(t *testing.T) {
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(429)
+		w.Write([]byte(`{"message":"rate limit"}`))
+	}))
+	defer ts.Close()
+
+	c := NewClient("token", ts.URL, AllowInsecureHTTP())
+	if err := c.SetRetryBackoff([]time.Duration{1 * time.Millisecond, 1 * time.Millisecond}); err != nil {
+		t.Fatalf("SetRetryBackoff: %v", err)
+	}
+
+	_, err := c.doJSONRequest(context.Background(), http.MethodPost, ts.URL+"/test", map[string]string{"key": "val"})
+	if err == nil {
+		t.Fatal("expected error after exhausting retries")
+	}
+	var apiErr *APIError
+	if !errors.As(err, &apiErr) {
+		t.Fatalf("expected APIError, got %T: %v", err, err)
+	}
+	if apiErr.StatusCode != 429 {
+		t.Errorf("expected 429, got %d", apiErr.StatusCode)
+	}
+}

github/conformance_test.go

@@ -0,0 +1,14 @@
+package github_test
+
+import (
+	"gitea.weiker.me/rodin/review-bot/github"
+	"gitea.weiker.me/rodin/review-bot/vcs"
+)
+
+// Compile-time interface conformance assertion.
+// This verifies github.Client satisfies the full vcs.Client interface
+// (PRReader, FileReader, Reviewer, Identity).
+var _ vcs.Client = (*github.Client)(nil)
+
+// Verify github.Client implements ReviewSuperseder.
+var _ vcs.ReviewSuperseder = (*github.Client)(nil)

github/files.go

@@ -0,0 +1,160 @@
+package github
+
+import (
+	"context"
+	"encoding/base64"
+	"encoding/json"
+	"fmt"
+	"net/url"
+	"path"
+	"strings"
+
+	"gitea.weiker.me/rodin/review-bot/vcs"
+)
+
+// GetFileContent fetches a file from a repo at the given ref.
+// Delegates to GetFileContentAtRef with the provided ref.
+func (c *Client) GetFileContent(ctx context.Context, owner, repo, filePath, ref string) (string, error) {
+	return c.GetFileContentAtRef(ctx, owner, repo, filePath, ref)
+}
+
+// GetFileContentAtRef fetches a file at a specific ref from a repo.
+// If ref is empty, the query parameter is omitted (uses default branch).
+//
+// Returns an error if the path contains dot-segments (".", "..") or
+// attempts to traverse above the repository root.
+func (c *Client) GetFileContentAtRef(ctx context.Context, owner, repo, filePath, ref string) (string, error) {
+	escaped, err := escapePath(filePath)
+	if err != nil {
+		return "", fmt.Errorf("invalid file path: %w", err)
+	}
+	reqURL := fmt.Sprintf("%s/repos/%s/%s/contents/%s",
+		c.baseURL, url.PathEscape(owner), url.PathEscape(repo), escaped)
+	if ref != "" {
+		reqURL += "?ref=" + url.QueryEscape(ref)
+	}
+	body, err := c.doGet(ctx, reqURL)
+	if err != nil {
+		return "", fmt.Errorf("fetch file %s: %w", filePath, err)
+	}
+	var resp struct {
+		Content  string `json:"content"`
+		Encoding string `json:"encoding"`
+	}
+	if err := json.Unmarshal(body, &resp); err != nil {
+		return "", fmt.Errorf("parse file content JSON: %w", err)
+	}
+	if resp.Encoding != "base64" {
+		return "", fmt.Errorf("unexpected encoding %q for file %s", resp.Encoding, filePath)
+	}
+	decoded, err := decodeBase64Content(resp.Content)
+	if err != nil {
+		return "", fmt.Errorf("decode base64 content for %s: %w", filePath, err)
+	}
+	return decoded, nil
+}
+
+// ListContents lists files and directories at a given path in a repo.
+// Returns the directory listing from the GitHub contents API.
+// If the path points to a single file (not a directory), the API returns
+// a JSON object instead of an array; this is handled by returning a
+// single-element slice.
+func (c *Client) ListContents(ctx context.Context, owner, repo, filePath string) ([]vcs.ContentEntry, error) {
+	escaped, err := escapePath(filePath)
+	if err != nil {
+		return nil, fmt.Errorf("invalid file path: %w", err)
+	}
+	reqURL := fmt.Sprintf("%s/repos/%s/%s/contents/%s",
+		c.baseURL, url.PathEscape(owner), url.PathEscape(repo), escaped)
+	body, err := c.doGet(ctx, reqURL)
+	if err != nil {
+		return nil, fmt.Errorf("list contents %s: %w", filePath, err)
+	}
+
+	type entry struct {
+		Name string `json:"name"`
+		Path string `json:"path"`
+		Type string `json:"type"`
+	}
+
+	// The GitHub contents API returns an array for directories and an object
+	// for single files. Try array first (common case), then fall back to object.
+	// An empty array ([]) is valid — it represents an empty directory — and
+	// results in a zero-length slice returned without error.
+	var entries []entry
+	if err := json.Unmarshal(body, &entries); err != nil {
+		var single entry
+		if err2 := json.Unmarshal(body, &single); err2 != nil {
+			return nil, fmt.Errorf("parse contents JSON: as array: %v; as object: %w", err, err2)
+		}
+		// Guard against empty objects ({}) or unexpected shapes that
+		// unmarshal successfully but carry no useful data.
+		if single.Name == "" && single.Path == "" && single.Type == "" {
+			return nil, fmt.Errorf("parse contents JSON: unexpected response format")
+		}
+		entries = []entry{single}
+	}
+
+	result := make([]vcs.ContentEntry, len(entries))
+	for i, e := range entries {
+		result[i] = vcs.ContentEntry{
+			Name: e.Name,
+			Path: e.Path,
+			Type: e.Type,
+		}
+	}
+	return result, nil
+}
+
+// escapePath validates and encodes a slash-separated file path for use in
+// GitHub API URLs. Returns an error if the path contains dot-segments ("."
+// or "..") or resolves to a path outside the repository root.
+func escapePath(p string) (string, error) {
+	// Reject paths containing dot-segments rather than silently rewriting them.
+	for _, seg := range strings.Split(p, "/") {
+		if seg == "." || seg == ".." {
+			return "", fmt.Errorf("path contains dot-segment %q: %s", seg, p)
+		}
+	}
+
+	// Use path.Clean for canonical form, then verify it doesn't escape root.
+	cleaned := path.Clean(p)
+	if cleaned == "." || strings.HasPrefix(cleaned, "..") {
+		return "", fmt.Errorf("path resolves outside repository root: %s", p)
+	}
+
+	// Encode each segment individually.
+	parts := strings.Split(cleaned, "/")
+	var encoded []string
+	for _, part := range parts {
+		if part == "" {
+			continue
+		}
+		encoded = append(encoded, url.PathEscape(part))
+	}
+	return strings.Join(encoded, "/"), nil
+}
+
+// maxFileContentSize is the maximum decoded file size (10 MB) to prevent
+// resource exhaustion when decoding base64 content from the API.
+const maxFileContentSize = 10 * 1024 * 1024
+
+// decodeBase64Content decodes base64-encoded content from the GitHub contents API.
+// GitHub returns base64 content with line breaks for formatting; we strip \r and \n before decoding.
+// Returns an error if the decoded content exceeds maxFileContentSize.
+func decodeBase64Content(encoded string) (string, error) {
+	cleaned := strings.NewReplacer("\n", "", "\r", "").Replace(encoded)
+	// Check estimated decoded size before allocating.
+	// Base64 encodes 3 bytes into 4 chars, so decoded ~ len*3/4.
+	if len(cleaned)*3/4 > maxFileContentSize {
+		return "", fmt.Errorf("file content too large: estimated %d bytes exceeds limit of %d", len(cleaned)*3/4, maxFileContentSize)
+	}
+	decoded, err := base64.StdEncoding.DecodeString(cleaned)
+	if err != nil {
+		return "", err
+	}
+	if len(decoded) > maxFileContentSize {
+		return "", fmt.Errorf("file content too large: %d bytes exceeds limit of %d", len(decoded), maxFileContentSize)
+	}
+	return string(decoded), nil
+}

github/files_test.go

@@ -0,0 +1,405 @@
+package github
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+	"time"
+)
+
+func TestGetFileContent_DelegatesToGetFileContentAtRef(t *testing.T) {
+	var gotRef string
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		gotRef = r.URL.Query().Get("ref")
+		json.NewEncoder(w).Encode(map[string]string{
+			"content":  "dGVzdA==", // "test" in base64
+			"encoding": "base64",
+		})
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+
+	// Call with empty ref — should not include ref param
+	content, err := c.GetFileContent(context.Background(), "owner", "repo", "file.go", "")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if content != "test" {
+		t.Errorf("expected 'test', got %q", content)
+	}
+	if gotRef != "" {
+		t.Errorf("expected empty ref, got %q", gotRef)
+	}
+}
+
+func TestGetFileContent_WithRef(t *testing.T) {
+	var gotRef string
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		gotRef = r.URL.Query().Get("ref")
+		json.NewEncoder(w).Encode(map[string]string{
+			"content":  "dGVzdA==",
+			"encoding": "base64",
+		})
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+
+	_, err := c.GetFileContent(context.Background(), "owner", "repo", "file.go", "abc123")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if gotRef != "abc123" {
+		t.Errorf("expected ref 'abc123', got %q", gotRef)
+	}
+}
+
+func TestGetFileContent_404(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(404)
+		w.Write([]byte(`{"message":"Not Found"}`))
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+
+	_, err := c.GetFileContent(context.Background(), "owner", "repo", "missing.go", "")
+	if err == nil {
+		t.Fatal("expected error for 404")
+	}
+}
+
+func TestGetFileContent_401(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(401)
+		w.Write([]byte(`{"message":"Bad credentials"}`))
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+
+	_, err := c.GetFileContent(context.Background(), "owner", "repo", "file.go", "")
+	if err == nil {
+		t.Fatal("expected error for 401")
+	}
+}
+
+func TestGetFileContent_429Retry(t *testing.T) {
+	attempts := 0
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		attempts++
+		if attempts == 1 {
+			w.WriteHeader(429)
+			w.Write([]byte(`{"message":"rate limit"}`))
+			return
+		}
+		json.NewEncoder(w).Encode(map[string]string{
+			"content":  "b2s=",
+			"encoding": "base64",
+		})
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+	if err := c.SetRetryBackoff([]time.Duration{1 * time.Millisecond, 1 * time.Millisecond}); err != nil {
+		t.Fatalf("SetRetryBackoff: %v", err)
+	}
+
+	content, err := c.GetFileContent(context.Background(), "owner", "repo", "file.go", "")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if content != "ok" {
+		t.Errorf("expected 'ok', got %q", content)
+	}
+	if attempts != 2 {
+		t.Errorf("expected 2 attempts, got %d", attempts)
+	}
+}
+
+func TestGetFileContent_MalformedJSON(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(200)
+		w.Write([]byte(`not json`))
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+
+	_, err := c.GetFileContent(context.Background(), "owner", "repo", "file.go", "")
+	if err == nil {
+		t.Fatal("expected error for malformed JSON")
+	}
+}
+
+func TestListContents_HappyPath(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path != "/repos/owner/repo/contents/src" {
+			t.Errorf("unexpected path: %s", r.URL.Path)
+		}
+		json.NewEncoder(w).Encode([]map[string]string{
+			{"name": "main.go", "path": "src/main.go", "type": "file"},
+			{"name": "lib", "path": "src/lib", "type": "dir"},
+		})
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+
+	entries, err := c.ListContents(context.Background(), "owner", "repo", "src")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if len(entries) != 2 {
+		t.Fatalf("expected 2 entries, got %d", len(entries))
+	}
+	if entries[0].Name != "main.go" {
+		t.Errorf("expected name 'main.go', got %q", entries[0].Name)
+	}
+	if entries[0].Path != "src/main.go" {
+		t.Errorf("expected path 'src/main.go', got %q", entries[0].Path)
+	}
+	if entries[0].Type != "file" {
+		t.Errorf("expected type 'file', got %q", entries[0].Type)
+	}
+	if entries[1].Name != "lib" {
+		t.Errorf("expected name 'lib', got %q", entries[1].Name)
+	}
+	if entries[1].Type != "dir" {
+		t.Errorf("expected type 'dir', got %q", entries[1].Type)
+	}
+}
+
+func TestListContents_404(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(404)
+		w.Write([]byte(`{"message":"Not Found"}`))
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+
+	_, err := c.ListContents(context.Background(), "owner", "repo", "missing")
+	if err == nil {
+		t.Fatal("expected error for 404")
+	}
+}
+
+func TestListContents_401(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(401)
+		w.Write([]byte(`{"message":"Bad credentials"}`))
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+
+	_, err := c.ListContents(context.Background(), "owner", "repo", "src")
+	if err == nil {
+		t.Fatal("expected error for 401")
+	}
+}
+
+func TestListContents_429Retry(t *testing.T) {
+	attempts := 0
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		attempts++
+		if attempts == 1 {
+			w.WriteHeader(429)
+			w.Write([]byte(`{"message":"rate limit"}`))
+			return
+		}
+		json.NewEncoder(w).Encode([]map[string]string{
+			{"name": "file.go", "path": "file.go", "type": "file"},
+		})
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+	if err := c.SetRetryBackoff([]time.Duration{1 * time.Millisecond, 1 * time.Millisecond}); err != nil {
+		t.Fatalf("SetRetryBackoff: %v", err)
+	}
+
+	entries, err := c.ListContents(context.Background(), "owner", "repo", "src")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if len(entries) != 1 {
+		t.Fatalf("expected 1 entry, got %d", len(entries))
+	}
+	if attempts != 2 {
+		t.Errorf("expected 2 attempts, got %d", attempts)
+	}
+}
+
+func TestListContents_MalformedJSON(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(200)
+		w.Write([]byte(`not json`))
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+
+	_, err := c.ListContents(context.Background(), "owner", "repo", "src")
+	if err == nil {
+		t.Fatal("expected error for malformed JSON")
+	}
+}
+
+func TestListContents_SingleFile(t *testing.T) {
+	// GitHub Contents API returns a JSON object (not array) for single-file paths
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(200)
+		w.Write([]byte(`{"name":"README.md","path":"README.md","type":"file"}`))
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+	entries, err := c.ListContents(context.Background(), "owner", "repo", "README.md")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if len(entries) != 1 {
+		t.Fatalf("expected 1 entry, got %d", len(entries))
+	}
+	if entries[0].Name != "README.md" {
+		t.Errorf("expected name 'README.md', got %q", entries[0].Name)
+	}
+	if entries[0].Type != "file" {
+		t.Errorf("expected type 'file', got %q", entries[0].Type)
+	}
+}
+
+func TestEscapePath_ValidPaths(t *testing.T) {
+	t.Parallel()
+	tests := []struct {
+		name string
+		path string
+		want string
+	}{
+		{"simple file", "file.go", "file.go"},
+		{"nested path", "path/to/file.go", "path/to/file.go"},
+		{"special chars", "path/to/my file.go", "path/to/my%20file.go"},
+		{"leading slash stripped", "/path/to/file.go", "path/to/file.go"},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+			got, err := escapePath(tt.path)
+			if err != nil {
+				t.Fatalf("unexpected error: %v", err)
+			}
+			if got != tt.want {
+				t.Errorf("escapePath(%q) = %q, want %q", tt.path, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestEscapePath_DotSegments(t *testing.T) {
+	t.Parallel()
+	tests := []struct {
+		name string
+		path string
+	}{
+		{"single dot", "./file.go"},
+		{"double dot", "../file.go"},
+		{"dot in middle", "path/./file.go"},
+		{"parent traversal", "path/../file.go"},
+		{"only dots", ".."},
+		{"nested parent traversal", "a/b/../../c"},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+			_, err := escapePath(tt.path)
+			if err == nil {
+				t.Fatalf("expected error for path %q, got nil", tt.path)
+			}
+			if !strings.Contains(err.Error(), "dot-segment") {
+				t.Errorf("expected error about dot-segment, got: %v", err)
+			}
+		})
+	}
+}
+
+func TestGetFileContentAtRef_DotSegmentError(t *testing.T) {
+	// Server should never be called — the error is caught before the request.
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		t.Fatal("server should not have been called")
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	_, err := c.GetFileContentAtRef(context.Background(), "owner", "repo", "foo/../bar.go", "main")
+	if err == nil {
+		t.Fatal("expected error for path with dot-segments")
+	}
+	if !strings.Contains(err.Error(), "invalid file path") {
+		t.Errorf("expected 'invalid file path' error, got: %v", err)
+	}
+}
+
+func TestDecodeBase64Content(t *testing.T) {
+	// Test with newlines (GitHub's format)
+	encoded := "cGFja2FnZSBt\nYWlu"
+	decoded, err := decodeBase64Content(encoded)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if decoded != "package main" {
+		t.Errorf("expected 'package main', got %q", decoded)
+	}
+}
+
+func TestDecodeBase64Content_Invalid(t *testing.T) {
+	_, err := decodeBase64Content("not!!!valid!!!base64")
+	if err == nil {
+		t.Fatal("expected error for invalid base64")
+	}
+}
+
+func TestDecodeBase64Content_CRLF(t *testing.T) {
+	// Base64 of "hello world" with CRLF line breaks inserted
+	encoded := "aGVs\r\nbG8g\r\nd29y\r\nbGQ="
+	decoded, err := decodeBase64Content(encoded)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if decoded != "hello world" {
+		t.Errorf("expected 'hello world', got %q", decoded)
+	}
+}
+
+func TestDecodeBase64Content_SizeLimit(t *testing.T) {
+	t.Parallel()
+	// Create base64 content that would decode to > maxFileContentSize.
+	// maxFileContentSize is 10MB. Base64 of 11MB worth of zeros.
+	// We just need something big enough to trigger the estimated size check.
+	// 14MB of base64 chars (decodes to ~10.5MB).
+	huge := strings.Repeat("A", 14*1024*1024)
+	_, err := decodeBase64Content(huge)
+	if err == nil {
+		t.Fatal("expected error for oversized content")
+	}
+	if !strings.Contains(err.Error(), "too large") {
+		t.Errorf("expected 'too large' error, got: %v", err)
+	}
+}

github/helpers_test.go

@@ -0,0 +1,23 @@
+package github
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+	"time"
+)
+
+// newTestClient creates a *Client backed by an httptest.Server running the
+// given handler. The server is automatically closed when the test finishes.
+// Shared across test files in package github.
+func newTestClient(t *testing.T, handler http.HandlerFunc) *Client {
+	t.Helper()
+	srv := httptest.NewServer(handler)
+	t.Cleanup(srv.Close)
+	c := NewClient("test-token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+	if err := c.SetRetryBackoff([]time.Duration{1 * time.Millisecond, 1 * time.Millisecond}); err != nil {
+		t.Fatalf("SetRetryBackoff: %v", err)
+	}
+	return c
+}

github/identity_test.go

@@ -0,0 +1,46 @@
+package github
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+	"testing"
+)
+
+func TestGetAuthenticatedUser_HappyPath(t *testing.T) {
+	c := newTestClient(t, func(w http.ResponseWriter, r *http.Request) {
+		if r.Method != "GET" {
+			t.Errorf("expected GET, got %s", r.Method)
+		}
+		if r.URL.Path != "/user" {
+			t.Errorf("unexpected path: %s", r.URL.Path)
+		}
+		if r.Header.Get("Authorization") != "Bearer test-token" {
+			t.Errorf("unexpected auth header: %s", r.Header.Get("Authorization"))
+		}
+		json.NewEncoder(w).Encode(map[string]string{"login": "review-bot"})
+	})
+
+	login, err := c.GetAuthenticatedUser(context.Background())
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if login != "review-bot" {
+		t.Errorf("expected login 'review-bot', got %q", login)
+	}
+}
+
+func TestGetAuthenticatedUser_401(t *testing.T) {
+	c := newTestClient(t, func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(401)
+		w.Write([]byte(`{"message":"Bad credentials"}`))
+	})
+
+	_, err := c.GetAuthenticatedUser(context.Background())
+	if err == nil {
+		t.Fatal("expected error for 401")
+	}
+	if !IsUnauthorized(err) {
+		t.Errorf("expected IsUnauthorized=true, got error: %v", err)
+	}
+}

github/pr.go

@@ -0,0 +1,222 @@
+package github
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/url"
+
+	"gitea.weiker.me/rodin/review-bot/vcs"
+)
+
+// pullRequestResponse is the GitHub API response for a pull request.
+type pullRequestResponse struct {
+	Number int    `json:"number"`
+	Title  string `json:"title"`
+	Body   string `json:"body"`
+	Head   struct {
+		SHA string `json:"sha"`
+		Ref string `json:"ref"`
+	} `json:"head"`
+	Base struct {
+		Ref string `json:"ref"`
+	} `json:"base"`
+}
+
+// changedFileResponse is the GitHub API response for a changed file in a PR.
+type changedFileResponse struct {
+	Filename string `json:"filename"`
+	Status   string `json:"status"`
+	Patch    string `json:"patch"`
+}
+
+// commitStatusResponse is the GitHub combined status API response.
+type commitStatusResponse struct {
+	Statuses []struct {
+		Context     string `json:"context"`
+		State       string `json:"state"`
+		Description string `json:"description"`
+		TargetURL   string `json:"target_url"`
+	} `json:"statuses"`
+}
+
+// checkRunsResponse is the GitHub check runs API response.
+type checkRunsResponse struct {
+	CheckRuns []struct {
+		Name       string  `json:"name"`
+		Conclusion *string `json:"conclusion"`
+		Status     string  `json:"status"`
+		HTMLURL    string  `json:"html_url"`
+	} `json:"check_runs"`
+}
+
+// GetPullRequest fetches PR metadata from the GitHub API.
+// Returns an *APIError wrapping the HTTP status on non-2xx responses (e.g.
+// IsNotFound for 404, IsUnauthorized for 401). Network and context errors
+// are wrapped but not typed as *APIError.
+func (c *Client) GetPullRequest(ctx context.Context, owner, repo string, number int) (*vcs.PullRequest, error) {
+	reqURL := fmt.Sprintf("%s/repos/%s/%s/pulls/%d", c.baseURL, url.PathEscape(owner), url.PathEscape(repo), number)
+	body, err := c.doGet(ctx, reqURL)
+	if err != nil {
+		return nil, fmt.Errorf("fetch PR: %w", err)
+	}
+	var resp pullRequestResponse
+	if err := json.Unmarshal(body, &resp); err != nil {
+		return nil, fmt.Errorf("parse PR JSON: %w", err)
+	}
+	return &vcs.PullRequest{
+		Number: resp.Number,
+		Title:  resp.Title,
+		Body:   resp.Body,
+		Head:   vcs.HeadRef{SHA: resp.Head.SHA, Ref: resp.Head.Ref},
+		Base:   vcs.BaseRef{Ref: resp.Base.Ref},
+	}, nil
+}
+
+// GetPullRequestDiff fetches the unified diff for a PR.
+// Uses Accept: application/vnd.github.diff to get raw diff text.
+func (c *Client) GetPullRequestDiff(ctx context.Context, owner, repo string, number int) (string, error) {
+	reqURL := fmt.Sprintf("%s/repos/%s/%s/pulls/%d", c.baseURL, url.PathEscape(owner), url.PathEscape(repo), number)
+	body, err := c.doRequest(ctx, http.MethodGet, reqURL, "application/vnd.github.diff")
+	if err != nil {
+		return "", fmt.Errorf("fetch diff: %w", err)
+	}
+	return string(body), nil
+}
+
+const (
+	// maxFilesPages is the upper bound on pagination loops for PR file listing,
+	// preventing unbounded iteration if the server always returns a full page.
+	maxFilesPages = 100
+
+	// maxCheckRunPages is the upper bound on pagination loops for check-run listing,
+	// preventing unbounded iteration if the server always returns a full page.
+	maxCheckRunPages = 100
+)
+
+// GetPullRequestFiles fetches the list of files changed in a PR.
+// Paginates through all pages (100 per page) to collect all files.
+// Returns nil (not an empty slice) when the PR has no changed files.
+// Callers can safely range over or check len() on a nil slice.
+func (c *Client) GetPullRequestFiles(ctx context.Context, owner, repo string, number int) ([]vcs.ChangedFile, error) {
+	var allFiles []vcs.ChangedFile
+
+	for page := 1; page <= maxFilesPages; page++ {
+		reqURL := fmt.Sprintf("%s/repos/%s/%s/pulls/%d/files?per_page=100&page=%d",
+			c.baseURL, url.PathEscape(owner), url.PathEscape(repo), number, page)
+		body, err := c.doGet(ctx, reqURL)
+		if err != nil {
+			return nil, fmt.Errorf("fetch PR files page %d: %w", page, err)
+		}
+		var files []changedFileResponse
+		if err := json.Unmarshal(body, &files); err != nil {
+			return nil, fmt.Errorf("parse PR files JSON: %w", err)
+		}
+		if len(files) == 0 {
+			break
+		}
+		for _, f := range files {
+			allFiles = append(allFiles, vcs.ChangedFile{
+				Filename: f.Filename,
+				Status:   f.Status,
+				Patch:    f.Patch,
+			})
+		}
+		if len(files) < 100 {
+			break
+		}
+	}
+
+	return allFiles, nil
+}
+
+// GetCommitStatuses fetches both commit statuses and check runs for a SHA,
+// merging them into a unified []vcs.CommitStatus slice.
+// Returns nil (not an empty slice) when there are no statuses or check runs.
+// If the commit statuses endpoint fails (e.g. 404 for an unknown SHA), the
+// function returns immediately without attempting the check-runs endpoint.
+// If the check-runs endpoint fails after statuses were fetched successfully,
+// the function returns an error (not a partial result) so callers always get
+// either a complete view or a clear error signal.
+func (c *Client) GetCommitStatuses(ctx context.Context, owner, repo, sha string) ([]vcs.CommitStatus, error) {
+	var result []vcs.CommitStatus
+
+	// Fetch commit statuses
+	statusURL := fmt.Sprintf("%s/repos/%s/%s/commits/%s/status",
+		c.baseURL, url.PathEscape(owner), url.PathEscape(repo), url.PathEscape(sha))
+	statusBody, err := c.doGet(ctx, statusURL)
+	if err != nil {
+		return nil, fmt.Errorf("fetch commit statuses: %w", err)
+	}
+	var statusResp commitStatusResponse
+	if err := json.Unmarshal(statusBody, &statusResp); err != nil {
+		return nil, fmt.Errorf("parse commit statuses JSON: %w", err)
+	}
+	for _, s := range statusResp.Statuses {
+		result = append(result, vcs.CommitStatus{
+			Context:     s.Context,
+			Status:      s.State,
+			Description: s.Description,
+			TargetURL:   s.TargetURL,
+		})
+	}
+
+	// Fetch check runs (paginated)
+	for checkPage := 1; checkPage <= maxCheckRunPages; checkPage++ {
+		checkURL := fmt.Sprintf("%s/repos/%s/%s/commits/%s/check-runs?per_page=100&page=%d",
+			c.baseURL, url.PathEscape(owner), url.PathEscape(repo), url.PathEscape(sha), checkPage)
+		checkBody, err := c.doGet(ctx, checkURL)
+		if err != nil {
+			return nil, fmt.Errorf("fetch check runs page %d: %w", checkPage, err)
+		}
+		var checkResp checkRunsResponse
+		if err := json.Unmarshal(checkBody, &checkResp); err != nil {
+			return nil, fmt.Errorf("parse check runs JSON: %w", err)
+		}
+		for _, cr := range checkResp.CheckRuns {
+			result = append(result, vcs.CommitStatus{
+				Context:     cr.Name,
+				Status:      mapCheckRunStatus(cr.Conclusion),
+				Description: "", // check runs have no human-readable description; conclusion is captured in Status
+				TargetURL:   cr.HTMLURL,
+			})
+		}
+		if len(checkResp.CheckRuns) < 100 {
+			break
+		}
+	}
+
+	return result, nil
+}
+
+// mapCheckRunStatus maps a GitHub check run conclusion to a vcs.CommitStatus status string.
+// Conclusion alone determines the mapped state: nil conclusion means the run is
+// still in progress (pending), regardless of the status field value.
+//
+// Mapping rules:
+//   - nil → "pending" (run still in progress or queued)
+//   - "success" → "success"
+//   - "failure", "action_required", "timed_out" → "failure"
+//   - "cancelled", "skipped", "neutral" → "success" (non-blocking per GitHub check suite semantics)
+//   - "stale" → "pending" (check run became stale before completing)
+//   - unknown values → "pending" (conservative: treat unrecognized conclusions as incomplete)
+func mapCheckRunStatus(conclusion *string) string {
+	if conclusion == nil {
+		// Still running or queued
+		return "pending"
+	}
+	switch *conclusion {
+	case "success":
+		return "success"
+	case "failure", "action_required", "timed_out":
+		return "failure"
+	case "cancelled", "skipped", "neutral":
+		return "success" // non-blocking: these do not indicate a blocking failure per GitHub check suite semantics
+	case "stale":
+		return "pending"
+	default:
+		return "pending"
+	}
+}
+

github/pr_test.go

@@ -0,0 +1,676 @@
+package github
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+	"time"
+)
+
+func TestGetPullRequest_HappyPath(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path != "/repos/owner/repo/pulls/42" {
+			t.Errorf("unexpected path: %s", r.URL.Path)
+		}
+		json.NewEncoder(w).Encode(map[string]interface{}{
+			"number": 42,
+			"title":  "Test PR",
+			"body":   "Description",
+			"head":   map[string]string{"sha": "abc123", "ref": "feature-branch"},
+			"base":   map[string]string{"ref": "main"},
+		})
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+
+	pr, err := c.GetPullRequest(context.Background(), "owner", "repo", 42)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if pr.Number != 42 {
+		t.Errorf("expected number 42, got %d", pr.Number)
+	}
+	if pr.Title != "Test PR" {
+		t.Errorf("expected title 'Test PR', got %q", pr.Title)
+	}
+	if pr.Body != "Description" {
+		t.Errorf("expected body 'Description', got %q", pr.Body)
+	}
+	if pr.Head.SHA != "abc123" {
+		t.Errorf("expected head SHA 'abc123', got %q", pr.Head.SHA)
+	}
+	if pr.Head.Ref != "feature-branch" {
+		t.Errorf("expected head ref 'feature-branch', got %q", pr.Head.Ref)
+	}
+	if pr.Base.Ref != "main" {
+		t.Errorf("expected base ref 'main', got %q", pr.Base.Ref)
+	}
+}
+
+func TestGetPullRequest_404(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(404)
+		w.Write([]byte(`{"message":"Not Found"}`))
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+
+	_, err := c.GetPullRequest(context.Background(), "owner", "repo", 999)
+	if err == nil {
+		t.Fatal("expected error for 404")
+	}
+	if !IsNotFound(err) {
+		t.Errorf("expected IsNotFound=true, got error: %v", err)
+	}
+}
+
+func TestGetPullRequest_401(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(401)
+		w.Write([]byte(`{"message":"Bad credentials"}`))
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+
+	_, err := c.GetPullRequest(context.Background(), "owner", "repo", 1)
+	if err == nil {
+		t.Fatal("expected error for 401")
+	}
+	if !IsUnauthorized(err) {
+		t.Errorf("expected IsUnauthorized=true, got error: %v", err)
+	}
+}
+
+func TestGetPullRequest_429Retry(t *testing.T) {
+	attempts := 0
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		attempts++
+		if attempts == 1 {
+			w.WriteHeader(429)
+			w.Write([]byte(`{"message":"rate limit"}`))
+			return
+		}
+		json.NewEncoder(w).Encode(map[string]interface{}{
+			"number": 1,
+			"title":  "PR",
+			"body":   "",
+			"head":   map[string]string{"sha": "abc", "ref": "br"},
+			"base":   map[string]string{"ref": "main"},
+		})
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+	c.SetRetryBackoff([]time.Duration{1 * time.Millisecond})
+
+	pr, err := c.GetPullRequest(context.Background(), "owner", "repo", 1)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if pr.Number != 1 {
+		t.Errorf("expected number 1, got %d", pr.Number)
+	}
+	if attempts != 2 {
+		t.Errorf("expected 2 attempts, got %d", attempts)
+	}
+}
+
+func TestGetPullRequest_MalformedJSON(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(200)
+		w.Write([]byte(`{invalid json`))
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+
+	_, err := c.GetPullRequest(context.Background(), "owner", "repo", 1)
+	if err == nil {
+		t.Fatal("expected error for malformed JSON")
+	}
+	if !strings.Contains(err.Error(), "parse PR JSON") {
+		t.Errorf("expected parse error, got: %v", err)
+	}
+}
+
+func TestGetPullRequestDiff_HappyPath(t *testing.T) {
+	expectedDiff := "diff --git a/file.go b/file.go\n--- a/file.go\n+++ b/file.go\n@@ -1,3 +1,4 @@\n+// new line\n"
+	var gotAccept string
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		gotAccept = r.Header.Get("Accept")
+		w.WriteHeader(200)
+		w.Write([]byte(expectedDiff))
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+
+	diff, err := c.GetPullRequestDiff(context.Background(), "owner", "repo", 42)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if diff != expectedDiff {
+		t.Errorf("unexpected diff: %q", diff)
+	}
+	if gotAccept != "application/vnd.github.diff" {
+		t.Errorf("expected diff Accept header, got %q", gotAccept)
+	}
+}
+
+func TestGetPullRequestDiff_404(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(404)
+		w.Write([]byte(`{"message":"Not Found"}`))
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+
+	_, err := c.GetPullRequestDiff(context.Background(), "owner", "repo", 999)
+	if err == nil {
+		t.Fatal("expected error for 404")
+	}
+}
+
+func TestGetPullRequestDiff_401(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(401)
+		w.Write([]byte(`{"message":"Bad credentials"}`))
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+
+	_, err := c.GetPullRequestDiff(context.Background(), "owner", "repo", 1)
+	if err == nil {
+		t.Fatal("expected error for 401")
+	}
+}
+
+func TestGetPullRequestFiles_HappyPath(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		json.NewEncoder(w).Encode([]map[string]interface{}{
+			{"filename": "main.go", "status": "modified", "patch": "@@ -1,3 +1,4 @@\n+line"},
+			{"filename": "test.go", "status": "added", "patch": "@@ -0,0 +1,5 @@\n+new file"},
+		})
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+
+	files, err := c.GetPullRequestFiles(context.Background(), "owner", "repo", 1)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if len(files) != 2 {
+		t.Fatalf("expected 2 files, got %d", len(files))
+	}
+	if files[0].Filename != "main.go" {
+		t.Errorf("expected filename 'main.go', got %q", files[0].Filename)
+	}
+	if files[0].Status != "modified" {
+		t.Errorf("expected status 'modified', got %q", files[0].Status)
+	}
+	if files[0].Patch != "@@ -1,3 +1,4 @@\n+line" {
+		t.Errorf("unexpected patch: %q", files[0].Patch)
+	}
+}
+
+func TestGetPullRequestFiles_Pagination(t *testing.T) {
+	// Simulate > 100 files requiring pagination
+	page1Files := make([]map[string]string, 100)
+	for i := 0; i < 100; i++ {
+		page1Files[i] = map[string]string{
+			"filename": fmt.Sprintf("file%d.go", i),
+			"status":   "modified",
+			"patch":    fmt.Sprintf("patch%d", i),
+		}
+	}
+	page2Files := []map[string]string{
+		{"filename": "file100.go", "status": "added", "patch": "patch100"},
+	}
+
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		page := r.URL.Query().Get("page")
+		if page == "" || page == "1" {
+			json.NewEncoder(w).Encode(page1Files)
+		} else {
+			json.NewEncoder(w).Encode(page2Files)
+		}
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+
+	files, err := c.GetPullRequestFiles(context.Background(), "owner", "repo", 1)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if len(files) != 101 {
+		t.Errorf("expected 101 files (paginated), got %d", len(files))
+	}
+	if files[100].Filename != "file100.go" {
+		t.Errorf("expected last file 'file100.go', got %q", files[100].Filename)
+	}
+	if files[100].Patch != "patch100" {
+		t.Errorf("expected last patch 'patch100', got %q", files[100].Patch)
+	}
+}
+
+func TestGetPullRequestFiles_BinaryFile_NoPatch(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		// Binary files have no patch field in GitHub response
+		json.NewEncoder(w).Encode([]map[string]interface{}{
+			{"filename": "image.png", "status": "added"},
+		})
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+
+	files, err := c.GetPullRequestFiles(context.Background(), "owner", "repo", 1)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if len(files) != 1 {
+		t.Fatalf("expected 1 file, got %d", len(files))
+	}
+	if files[0].Patch != "" {
+		t.Errorf("expected empty patch for binary file, got %q", files[0].Patch)
+	}
+}
+
+func TestGetPullRequestFiles_404(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(404)
+		w.Write([]byte(`{"message":"Not Found"}`))
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+
+	_, err := c.GetPullRequestFiles(context.Background(), "owner", "repo", 999)
+	if err == nil {
+		t.Fatal("expected error for 404")
+	}
+}
+
+func TestGetPullRequestFiles_MalformedJSON(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(200)
+		w.Write([]byte(`not json`))
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+
+	_, err := c.GetPullRequestFiles(context.Background(), "owner", "repo", 1)
+	if err == nil {
+		t.Fatal("expected error for malformed JSON")
+	}
+}
+
+func TestGetFileContentAtRef_HappyPath(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path != "/repos/owner/repo/contents/path/to/file.go" {
+			t.Errorf("unexpected path: %s", r.URL.Path)
+		}
+		if r.URL.Query().Get("ref") != "abc123" {
+			t.Errorf("unexpected ref: %s", r.URL.Query().Get("ref"))
+		}
+		json.NewEncoder(w).Encode(map[string]string{
+			"content":  "cGFja2FnZSBtYWlu", // "package main" in base64
+			"encoding": "base64",
+		})
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+
+	content, err := c.GetFileContentAtRef(context.Background(), "owner", "repo", "path/to/file.go", "abc123")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if content != "package main" {
+		t.Errorf("expected 'package main', got %q", content)
+	}
+}
+
+func TestGetFileContentAtRef_EmptyRef(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Query().Get("ref") != "" {
+			t.Errorf("expected no ref param, got %q", r.URL.Query().Get("ref"))
+		}
+		json.NewEncoder(w).Encode(map[string]string{
+			"content":  "aGVsbG8=", // "hello" in base64
+			"encoding": "base64",
+		})
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+
+	content, err := c.GetFileContentAtRef(context.Background(), "owner", "repo", "file.txt", "")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if content != "hello" {
+		t.Errorf("expected 'hello', got %q", content)
+	}
+}
+
+func TestGetFileContentAtRef_404(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(404)
+		w.Write([]byte(`{"message":"Not Found"}`))
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+
+	_, err := c.GetFileContentAtRef(context.Background(), "owner", "repo", "missing.go", "main")
+	if err == nil {
+		t.Fatal("expected error for 404")
+	}
+}
+
+func TestGetFileContentAtRef_401(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(401)
+		w.Write([]byte(`{"message":"Bad credentials"}`))
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+
+	_, err := c.GetFileContentAtRef(context.Background(), "owner", "repo", "file.go", "main")
+	if err == nil {
+		t.Fatal("expected error for 401")
+	}
+}
+
+func TestGetFileContentAtRef_MalformedJSON(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(200)
+		w.Write([]byte(`not valid json`))
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+
+	_, err := c.GetFileContentAtRef(context.Background(), "owner", "repo", "file.go", "main")
+	if err == nil {
+		t.Fatal("expected error for malformed JSON")
+	}
+}
+
+func TestGetFileContentAtRef_429Retry(t *testing.T) {
+	attempts := 0
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		attempts++
+		if attempts == 1 {
+			w.WriteHeader(429)
+			w.Write([]byte(`{"message":"rate limit"}`))
+			return
+		}
+		json.NewEncoder(w).Encode(map[string]string{
+			"content":  "b2s=", // "ok" in base64
+			"encoding": "base64",
+		})
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+	c.SetRetryBackoff([]time.Duration{1 * time.Millisecond})
+
+	content, err := c.GetFileContentAtRef(context.Background(), "owner", "repo", "file.go", "main")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if content != "ok" {
+		t.Errorf("expected 'ok', got %q", content)
+	}
+	if attempts != 2 {
+		t.Errorf("expected 2 attempts, got %d", attempts)
+	}
+}
+
+func TestGetCommitStatuses_HappyPath(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		switch {
+		case strings.Contains(r.URL.Path, "/status"):
+			json.NewEncoder(w).Encode(map[string]interface{}{
+				"state": "success",
+				"statuses": []map[string]string{
+					{
+						"context":     "ci/build",
+						"state":       "success",
+						"description": "Build passed",
+						"target_url":  "https://ci.example.com/1",
+					},
+				},
+			})
+		case strings.Contains(r.URL.Path, "/check-runs"):
+			conclusion := "success"
+			json.NewEncoder(w).Encode(map[string]interface{}{
+				"total_count": 1,
+				"check_runs": []map[string]interface{}{
+					{
+						"name":       "lint",
+						"conclusion": &conclusion,
+						"status":     "completed",
+						"html_url":   "https://github.com/check/1",
+					},
+				},
+			})
+		default:
+			t.Errorf("unexpected path: %s", r.URL.Path)
+			w.WriteHeader(404)
+		}
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+
+	statuses, err := c.GetCommitStatuses(context.Background(), "owner", "repo", "abc123")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if len(statuses) != 2 {
+		t.Fatalf("expected 2 statuses, got %d", len(statuses))
+	}
+	// First should be from commit statuses
+	if statuses[0].Context != "ci/build" {
+		t.Errorf("expected context 'ci/build', got %q", statuses[0].Context)
+	}
+	if statuses[0].Status != "success" {
+		t.Errorf("expected status 'success', got %q", statuses[0].Status)
+	}
+	// Second should be from check runs
+	if statuses[1].Context != "lint" {
+		t.Errorf("expected context 'lint', got %q", statuses[1].Context)
+	}
+	if statuses[1].Status != "success" {
+		t.Errorf("expected status 'success', got %q", statuses[1].Status)
+	}
+}
+
+func TestGetCommitStatuses_CheckRunConclusions(t *testing.T) {
+	tests := []struct {
+		conclusion *string
+		status     string
+		want       string
+	}{
+		{stringPtr("success"), "completed", "success"},
+		{stringPtr("failure"), "completed", "failure"},
+		{stringPtr("action_required"), "completed", "failure"},
+		{stringPtr("timed_out"), "completed", "failure"},
+		{stringPtr("cancelled"), "completed", "success"},
+		{stringPtr("skipped"), "completed", "success"},
+		{stringPtr("neutral"), "completed", "success"},
+		{nil, "in_progress", "pending"},
+		{nil, "queued", "pending"},
+	}
+
+	for _, tt := range tests {
+		name := "nil"
+		if tt.conclusion != nil {
+			name = *tt.conclusion
+		}
+		t.Run(name, func(t *testing.T) {
+			t.Parallel()
+			srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+				if strings.Contains(r.URL.Path, "/status") {
+					json.NewEncoder(w).Encode(map[string]interface{}{
+						"state":    "success",
+						"statuses": []interface{}{},
+					})
+					return
+				}
+				json.NewEncoder(w).Encode(map[string]interface{}{
+					"total_count": 1,
+					"check_runs": []map[string]interface{}{
+						{
+							"name":       "check",
+							"conclusion": tt.conclusion,
+							"status":     tt.status,
+							"html_url":   "https://github.com/check/1",
+						},
+					},
+				})
+			}))
+			defer srv.Close()
+
+			c := NewClient("token", srv.URL, AllowInsecureHTTP())
+			c.SetHTTPClient(srv.Client())
+
+			statuses, err := c.GetCommitStatuses(context.Background(), "owner", "repo", "sha1")
+			if err != nil {
+				t.Fatalf("unexpected error: %v", err)
+			}
+			if len(statuses) != 1 {
+				t.Fatalf("expected 1 status, got %d", len(statuses))
+			}
+			if statuses[0].Status != tt.want {
+				t.Errorf("expected status %q, got %q", tt.want, statuses[0].Status)
+			}
+		})
+	}
+}
+
+func TestGetCommitStatuses_404(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(404)
+		w.Write([]byte(`{"message":"Not Found"}`))
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+
+	_, err := c.GetCommitStatuses(context.Background(), "owner", "repo", "badsha")
+	if err == nil {
+		t.Fatal("expected error for 404")
+	}
+}
+
+func TestGetCommitStatuses_401(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(401)
+		w.Write([]byte(`{"message":"Bad credentials"}`))
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+
+	_, err := c.GetCommitStatuses(context.Background(), "owner", "repo", "sha")
+	if err == nil {
+		t.Fatal("expected error for 401")
+	}
+}
+
+func TestGetCommitStatuses_MalformedJSON(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(200)
+		w.Write([]byte(`not json`))
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+
+	_, err := c.GetCommitStatuses(context.Background(), "owner", "repo", "sha")
+	if err == nil {
+		t.Fatal("expected error for malformed JSON")
+	}
+}
+
+func TestGetCommitStatuses_CheckRunsErrorAfterStatusesSucceed(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		switch {
+		case strings.Contains(r.URL.Path, "/status"):
+			// Statuses succeed
+			json.NewEncoder(w).Encode(map[string]interface{}{
+				"state": "success",
+				"statuses": []map[string]string{
+					{
+						"context":     "ci/build",
+						"state":       "success",
+						"description": "Build passed",
+						"target_url":  "https://ci.example.com/1",
+					},
+				},
+			})
+		case strings.Contains(r.URL.Path, "/check-runs"):
+			// Check runs fail with 500
+			w.WriteHeader(500)
+			w.Write([]byte(`{"message":"Internal Server Error"}`))
+		default:
+			w.WriteHeader(404)
+		}
+	}))
+	defer srv.Close()
+
+	c := NewClient("token", srv.URL, AllowInsecureHTTP())
+	c.SetHTTPClient(srv.Client())
+
+	_, err := c.GetCommitStatuses(context.Background(), "owner", "repo", "abc123")
+	if err == nil {
+		t.Fatal("expected error when check-runs endpoint fails after statuses succeed")
+	}
+	if !strings.Contains(err.Error(), "fetch check runs") {
+		t.Errorf("expected check runs error, got: %v", err)
+	}
+}
+
+func stringPtr(s string) *string {
+	return &s
+}

github/review_test.go

@@ -0,0 +1,677 @@
+package github
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"strings"
+	"testing"
+
+	"gitea.weiker.me/rodin/review-bot/vcs"
+)
+
+// --- PostReview tests ---
+
+func TestPostReview_HappyPath(t *testing.T) {
+	c := newTestClient(t, func(w http.ResponseWriter, r *http.Request) {
+		if r.Method != "POST" {
+			t.Fatalf("expected POST, got %s", r.Method)
+		}
+		if r.URL.Path != "/repos/owner/repo/pulls/5/reviews" {
+			t.Fatalf("unexpected path: %s", r.URL.Path)
+		}
+		if r.Header.Get("Content-Type") != "application/json" {
+			t.Errorf("expected Content-Type application/json, got %q", r.Header.Get("Content-Type"))
+		}
+
+		// Verify request body
+		body, _ := io.ReadAll(r.Body)
+		var req postReviewRequest
+		if err := json.Unmarshal(body, &req); err != nil {
+			t.Fatalf("unmarshal request: %v", err)
+		}
+		if req.Event != "APPROVE" {
+			t.Errorf("expected event APPROVE, got %q", req.Event)
+		}
+		if req.Body != "LGTM" {
+			t.Errorf("expected body 'LGTM', got %q", req.Body)
+		}
+		if req.CommitID != "abc123" {
+			t.Errorf("expected commit_id 'abc123', got %q", req.CommitID)
+		}
+		if len(req.Comments) != 1 {
+			t.Fatalf("expected 1 comment, got %d", len(req.Comments))
+		}
+		if req.Comments[0].Path != "main.go" {
+			t.Errorf("expected comment path 'main.go', got %q", req.Comments[0].Path)
+		}
+		if req.Comments[0].Position != 4 {
+			t.Errorf("expected comment position 4, got %d", req.Comments[0].Position)
+		}
+
+		json.NewEncoder(w).Encode(map[string]interface{}{
+			"id":        100,
+			"body":      "LGTM",
+			"state":     "APPROVED",
+			"commit_id": "abc123",
+			"user":      map[string]string{"login": "reviewer"},
+		})
+	})
+
+	review, err := c.PostReview(context.Background(), "owner", "repo", 5, vcs.ReviewRequest{
+		Body:  "LGTM",
+		Event: vcs.ReviewEventApprove,
+		Comments: []vcs.ReviewComment{
+			{Path: "main.go", Position: 4, CommitID: "abc123", Body: "nit: rename"},
+		},
+	})
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if review.ID != 100 {
+		t.Errorf("expected ID 100, got %d", review.ID)
+	}
+	if review.Body != "LGTM" {
+		t.Errorf("expected body 'LGTM', got %q", review.Body)
+	}
+	if review.State != "APPROVED" {
+		t.Errorf("expected state 'APPROVED', got %q", review.State)
+	}
+	if review.User.Login != "reviewer" {
+		t.Errorf("expected user 'reviewer', got %q", review.User.Login)
+	}
+	if review.CommitID != "abc123" {
+		t.Errorf("expected commit_id 'abc123', got %q", review.CommitID)
+	}
+}
+
+func TestPostReview_401(t *testing.T) {
+	c := newTestClient(t, func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(401)
+		w.Write([]byte(`{"message":"Bad credentials"}`))
+	})
+
+	_, err := c.PostReview(context.Background(), "owner", "repo", 5, vcs.ReviewRequest{
+		Body:  "LGTM",
+		Event: vcs.ReviewEventApprove,
+	})
+	if err == nil {
+		t.Fatal("expected error for 401")
+	}
+	if !IsUnauthorized(err) {
+		t.Errorf("expected IsUnauthorized=true, got error: %v", err)
+	}
+}
+
+func TestPostReview_422(t *testing.T) {
+	c := newTestClient(t, func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(422)
+		w.Write([]byte(`{"message":"Unprocessable Entity"}`))
+	})
+
+	_, err := c.PostReview(context.Background(), "owner", "repo", 5, vcs.ReviewRequest{
+		Body:  "LGTM",
+		Event: vcs.ReviewEventApprove,
+	})
+	if err == nil {
+		t.Fatal("expected error for 422")
+	}
+	// 422 should surface as a wrapped APIError
+	var apiErr *APIError
+	if !errors.As(err, &apiErr) {
+		t.Fatalf("expected *APIError, got %T: %v", err, err)
+	}
+	if apiErr.StatusCode != 422 {
+		t.Errorf("expected status 422, got %d", apiErr.StatusCode)
+	}
+}
+
+func TestPostReview_MalformedResponse(t *testing.T) {
+	c := newTestClient(t, func(w http.ResponseWriter, r *http.Request) {
+		w.Write([]byte(`not json`))
+	})
+
+	_, err := c.PostReview(context.Background(), "owner", "repo", 5, vcs.ReviewRequest{
+		Body:  "LGTM",
+		Event: vcs.ReviewEventApprove,
+	})
+	if err == nil {
+		t.Fatal("expected error for malformed response")
+	}
+	if !strings.Contains(err.Error(), "parse review response") {
+		t.Errorf("expected parse error, got: %v", err)
+	}
+}
+
+// --- ListReviews tests ---
+
+func TestListReviews_HappyPath(t *testing.T) {
+	c := newTestClient(t, func(w http.ResponseWriter, r *http.Request) {
+		if r.Method != "GET" {
+			t.Fatalf("expected GET, got %s", r.Method)
+		}
+		if r.URL.Path != "/repos/owner/repo/pulls/3/reviews" {
+			t.Fatalf("unexpected path: %s", r.URL.Path)
+		}
+		json.NewEncoder(w).Encode([]map[string]interface{}{
+			{
+				"id":        1,
+				"body":      "Approved",
+				"state":     "APPROVED",
+				"commit_id": "sha1",
+				"user":      map[string]string{"login": "user1"},
+			},
+			{
+				"id":        2,
+				"body":      "Needs work",
+				"state":     "CHANGES_REQUESTED",
+				"commit_id": "sha2",
+				"user":      map[string]string{"login": "user2"},
+			},
+			{
+				"id":        3,
+				"body":      "Comment only",
+				"state":     "COMMENTED",
+				"commit_id": "sha3",
+				"user":      map[string]string{"login": "user3"},
+			},
+			{
+				"id":        4,
+				"body":      "Old review",
+				"state":     "DISMISSED",
+				"commit_id": "sha4",
+				"user":      map[string]string{"login": "user4"},
+			},
+		})
+	})
+
+	reviews, err := c.ListReviews(context.Background(), "owner", "repo", 3)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if len(reviews) != 4 {
+		t.Fatalf("expected 4 reviews, got %d", len(reviews))
+	}
+
+	// Check state translation
+	expected := []struct {
+		id    int64
+		state string
+	}{
+		{1, "APPROVED"},
+		{2, "REQUEST_CHANGES"},
+		{3, "COMMENT"},
+		{4, "DISMISSED"},
+	}
+	for i, e := range expected {
+		if reviews[i].ID != e.id {
+			t.Errorf("review[%d]: expected ID %d, got %d", i, e.id, reviews[i].ID)
+		}
+		if reviews[i].State != e.state {
+			t.Errorf("review[%d]: expected state %q, got %q", i, e.state, reviews[i].State)
+		}
+	}
+}
+
+func TestListReviews_404(t *testing.T) {
+	c := newTestClient(t, func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(404)
+		w.Write([]byte(`{"message":"Not Found"}`))
+	})
+
+	_, err := c.ListReviews(context.Background(), "owner", "repo", 999)
+	if err == nil {
+		t.Fatal("expected error for 404")
+	}
+	if !IsNotFound(err) {
+		t.Errorf("expected IsNotFound=true, got error: %v", err)
+	}
+}
+
+func TestListReviews_401(t *testing.T) {
+	c := newTestClient(t, func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(401)
+		w.Write([]byte(`{"message":"Bad credentials"}`))
+	})
+
+	_, err := c.ListReviews(context.Background(), "owner", "repo", 3)
+	if err == nil {
+		t.Fatal("expected error for 401")
+	}
+	if !IsUnauthorized(err) {
+		t.Errorf("expected IsUnauthorized=true, got error: %v", err)
+	}
+}
+
+// --- DeleteReview tests ---
+
+func TestDeleteReview_HappyPath(t *testing.T) {
+	c := newTestClient(t, func(w http.ResponseWriter, r *http.Request) {
+		if r.Method != "DELETE" {
+			t.Fatalf("expected DELETE, got %s", r.Method)
+		}
+		if r.URL.Path != "/repos/owner/repo/pulls/5/reviews/42" {
+			t.Fatalf("unexpected path: %s", r.URL.Path)
+		}
+		w.WriteHeader(204)
+	})
+
+	err := c.DeleteReview(context.Background(), "owner", "repo", 5, 42)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+}
+
+func TestDeleteReview_422_SubmittedReview(t *testing.T) {
+	c := newTestClient(t, func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(422)
+		w.Write([]byte(`{"message":"Can not delete a non pending review"}`))
+	})
+
+	err := c.DeleteReview(context.Background(), "owner", "repo", 5, 42)
+	if err == nil {
+		t.Fatal("expected error for 422")
+	}
+	if !errors.Is(err, ErrCannotDeleteSubmittedReview) {
+		t.Errorf("expected ErrCannotDeleteSubmittedReview, got: %v", err)
+	}
+}
+
+// --- DismissReview tests ---
+
+func TestDismissReview_HappyPath(t *testing.T) {
+	c := newTestClient(t, func(w http.ResponseWriter, r *http.Request) {
+		if r.Method != "PUT" {
+			t.Fatalf("expected PUT, got %s", r.Method)
+		}
+		if r.URL.Path != "/repos/owner/repo/pulls/5/reviews/10/dismissals" {
+			t.Fatalf("unexpected path: %s", r.URL.Path)
+		}
+
+		body, _ := io.ReadAll(r.Body)
+		var req dismissReviewRequest
+		if err := json.Unmarshal(body, &req); err != nil {
+			t.Fatalf("unmarshal request: %v", err)
+		}
+		if req.Message != "Superseded by new review" {
+			t.Errorf("expected message 'Superseded by new review', got %q", req.Message)
+		}
+		if req.Event != "DISMISS" {
+			t.Errorf("expected event 'DISMISS', got %q", req.Event)
+		}
+
+		json.NewEncoder(w).Encode(map[string]interface{}{
+			"id":    10,
+			"state": "DISMISSED",
+		})
+	})
+
+	err := c.DismissReview(context.Background(), "owner", "repo", 5, 10, "Superseded by new review")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+}
+
+func TestDismissReview_404(t *testing.T) {
+	c := newTestClient(t, func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(404)
+		w.Write([]byte(`{"message":"Not Found"}`))
+	})
+
+	err := c.DismissReview(context.Background(), "owner", "repo", 5, 999, "dismiss")
+	if err == nil {
+		t.Fatal("expected error for 404")
+	}
+	if !IsNotFound(err) {
+		t.Errorf("expected IsNotFound=true, got error: %v", err)
+	}
+}
+
+func TestDismissReview_401(t *testing.T) {
+	c := newTestClient(t, func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(401)
+		w.Write([]byte(`{"message":"Bad credentials"}`))
+	})
+
+	err := c.DismissReview(context.Background(), "owner", "repo", 5, 10, "dismiss")
+	if err == nil {
+		t.Fatal("expected error for 401")
+	}
+	if !IsUnauthorized(err) {
+		t.Errorf("expected IsUnauthorized=true, got error: %v", err)
+	}
+}
+
+// --- State translation tests ---
+
+func TestTranslateGitHubReviewState(t *testing.T) {
+	tests := []struct {
+		name  string
+		input string
+		want  string
+	}{
+		{"approved passes through", "APPROVED", "APPROVED"},
+		{"changes_requested maps to REQUEST_CHANGES", "CHANGES_REQUESTED", "REQUEST_CHANGES"},
+		{"commented maps to COMMENT", "COMMENTED", "COMMENT"},
+		{"dismissed passes through", "DISMISSED", "DISMISSED"},
+		{"unknown state passes through", "UNKNOWN_STATE", "UNKNOWN_STATE"},
+		{"empty string passes through", "", ""},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := translateGitHubReviewState(tt.input)
+			if got != tt.want {
+				t.Errorf("translateGitHubReviewState(%q) = %q, want %q", tt.input, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestPostReview_ConflictingCommitIDs(t *testing.T) {
+	c := newTestClient(t, func(w http.ResponseWriter, r *http.Request) {
+		t.Fatal("request should not be sent when commit IDs conflict")
+	})
+
+	_, err := c.PostReview(context.Background(), "owner", "repo", 5, vcs.ReviewRequest{
+		Body:  "Review",
+		Event: vcs.ReviewEventComment,
+		Comments: []vcs.ReviewComment{
+			{Path: "a.go", Position: 1, CommitID: "sha-1", Body: "first"},
+			{Path: "b.go", Position: 2, CommitID: "sha-2", Body: "second"},
+		},
+	})
+	if err == nil {
+		t.Fatal("expected error for conflicting commit IDs")
+	}
+	if !errors.Is(err, ErrConflictingCommitIDs) {
+		t.Errorf("expected ErrConflictingCommitIDs, got: %v", err)
+	}
+}
+
+func TestPostReview_RequestCommitID_TakesPriority(t *testing.T) {
+	var gotPayload struct {
+		CommitID string `json:"commit_id"`
+		Body     string `json:"body"`
+	}
+
+	c := newTestClient(t, func(w http.ResponseWriter, r *http.Request) {
+		json.NewDecoder(r.Body).Decode(&gotPayload)
+		w.Header().Set("Content-Type", "application/json")
+		json.NewEncoder(w).Encode(map[string]any{
+			"id":        42,
+			"body":      "LGTM",
+			"state":     "APPROVED",
+			"commit_id": "req-level-sha",
+			"user":      map[string]any{"login": "bot"},
+		})
+	})
+
+	review, err := c.PostReview(context.Background(), "owner", "repo", 1, vcs.ReviewRequest{
+		Body:     "LGTM",
+		Event:    vcs.ReviewEventApprove,
+		CommitID: "req-level-sha",
+		Comments: []vcs.ReviewComment{
+			{Path: "a.go", Position: 1, CommitID: "req-level-sha", Body: "looks good"},
+		},
+	})
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if gotPayload.CommitID != "req-level-sha" {
+		t.Errorf("sent commit_id = %q, want %q", gotPayload.CommitID, "req-level-sha")
+	}
+	if review.CommitID != "req-level-sha" {
+		t.Errorf("review.CommitID = %q, want %q", review.CommitID, "req-level-sha")
+	}
+}
+
+func TestPostReview_RequestCommitID_ConflictsWithComment(t *testing.T) {
+	c := newTestClient(t, func(w http.ResponseWriter, r *http.Request) {
+		t.Fatal("request should not be sent when commit IDs conflict")
+	})
+
+	// req.CommitID is set, and a comment has a different CommitID → conflict
+	_, err := c.PostReview(context.Background(), "owner", "repo", 1, vcs.ReviewRequest{
+		Body:     "Review",
+		Event:    vcs.ReviewEventComment,
+		CommitID: "req-sha",
+		Comments: []vcs.ReviewComment{
+			{Path: "a.go", Position: 1, CommitID: "different-sha", Body: "nit"},
+		},
+	})
+	if err == nil {
+		t.Fatal("expected error for conflicting commit IDs")
+	}
+	if !errors.Is(err, ErrConflictingCommitIDs) {
+		t.Errorf("expected ErrConflictingCommitIDs, got: %v", err)
+	}
+}
+
+func TestPostReview_RequestCommitID_FallbackToComment(t *testing.T) {
+	var gotPayload struct {
+		CommitID string `json:"commit_id"`
+	}
+
+	c := newTestClient(t, func(w http.ResponseWriter, r *http.Request) {
+		json.NewDecoder(r.Body).Decode(&gotPayload)
+		w.Header().Set("Content-Type", "application/json")
+		json.NewEncoder(w).Encode(map[string]any{
+			"id":        43,
+			"body":      "ok",
+			"state":     "COMMENTED",
+			"commit_id": "comment-sha",
+			"user":      map[string]any{"login": "bot"},
+		})
+	})
+
+	// req.CommitID is empty, so it falls back to the comment's CommitID
+	_, err := c.PostReview(context.Background(), "owner", "repo", 1, vcs.ReviewRequest{
+		Body:  "ok",
+		Event: vcs.ReviewEventComment,
+		// CommitID intentionally empty
+		Comments: []vcs.ReviewComment{
+			{Path: "a.go", Position: 1, CommitID: "comment-sha", Body: "note"},
+		},
+	})
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if gotPayload.CommitID != "comment-sha" {
+		t.Errorf("sent commit_id = %q, want %q (fallback from comment)", gotPayload.CommitID, "comment-sha")
+	}
+}
+
+// --- ListReviews pagination tests ---
+
+func TestListReviews_MultiPage(t *testing.T) {
+	// Test multi-page pagination: 2 full pages + 1 partial page.
+	// pageSize=3, so pages return [3, 3, 2] reviews = 8 total.
+	const pageSize = 3
+	callCount := 0
+
+	c := newTestClient(t, func(w http.ResponseWriter, r *http.Request) {
+		if r.Method != "GET" {
+			t.Fatalf("expected GET, got %s", r.Method)
+		}
+		callCount++
+
+		page := r.URL.Query().Get("page")
+		var reviews []map[string]interface{}
+
+		switch page {
+		case "1":
+			for i := 1; i <= pageSize; i++ {
+				reviews = append(reviews, map[string]interface{}{
+					"id": i, "body": fmt.Sprintf("review %d", i),
+					"state": "APPROVED", "commit_id": "sha1",
+					"user": map[string]string{"login": "user1"},
+				})
+			}
+		case "2":
+			for i := pageSize + 1; i <= pageSize*2; i++ {
+				reviews = append(reviews, map[string]interface{}{
+					"id": i, "body": fmt.Sprintf("review %d", i),
+					"state": "COMMENTED", "commit_id": "sha1",
+					"user": map[string]string{"login": "user2"},
+				})
+			}
+		case "3":
+			// Partial page: only 2 reviews (less than pageSize)
+			for i := pageSize*2 + 1; i <= pageSize*2+2; i++ {
+				reviews = append(reviews, map[string]interface{}{
+					"id": i, "body": fmt.Sprintf("review %d", i),
+					"state": "CHANGES_REQUESTED", "commit_id": "sha1",
+					"user": map[string]string{"login": "user3"},
+				})
+			}
+		default:
+			t.Fatalf("unexpected page: %s", page)
+		}
+
+		json.NewEncoder(w).Encode(reviews)
+	})
+	c.SetReviewPagination(pageSize, 10)
+
+	reviews, err := c.ListReviews(context.Background(), "owner", "repo", 1)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if len(reviews) != 8 {
+		t.Fatalf("expected 8 reviews, got %d", len(reviews))
+	}
+	if callCount != 3 {
+		t.Errorf("expected 3 API calls, got %d", callCount)
+	}
+
+	// Verify reviews are correctly concatenated in order
+	for i, r := range reviews {
+		expectedID := int64(i + 1)
+		if r.ID != expectedID {
+			t.Errorf("review[%d]: expected ID %d, got %d", i, expectedID, r.ID)
+		}
+	}
+}
+
+func TestListReviews_ExactMultipleOfPageSize(t *testing.T) {
+	// When total reviews is an exact multiple of pageSize, an extra request
+	// returning 0 results terminates the loop. No truncation warning.
+	const pageSize = 2
+	callCount := 0
+
+	c := newTestClient(t, func(w http.ResponseWriter, r *http.Request) {
+		callCount++
+		page := r.URL.Query().Get("page")
+
+		var reviews []map[string]interface{}
+		switch page {
+		case "1":
+			reviews = []map[string]interface{}{
+				{"id": 1, "body": "r1", "state": "APPROVED", "commit_id": "s1", "user": map[string]string{"login": "u1"}},
+				{"id": 2, "body": "r2", "state": "APPROVED", "commit_id": "s1", "user": map[string]string{"login": "u2"}},
+			}
+		case "2":
+			reviews = []map[string]interface{}{
+				{"id": 3, "body": "r3", "state": "APPROVED", "commit_id": "s1", "user": map[string]string{"login": "u3"}},
+				{"id": 4, "body": "r4", "state": "APPROVED", "commit_id": "s1", "user": map[string]string{"login": "u4"}},
+			}
+		case "3":
+			// Empty page — signals end of data
+			reviews = []map[string]interface{}{}
+		default:
+			t.Fatalf("unexpected page: %s", page)
+		}
+
+		json.NewEncoder(w).Encode(reviews)
+	})
+	c.SetReviewPagination(pageSize, 10)
+
+	reviews, err := c.ListReviews(context.Background(), "owner", "repo", 1)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if len(reviews) != 4 {
+		t.Fatalf("expected 4 reviews, got %d", len(reviews))
+	}
+	// 3 calls: page 1 (full), page 2 (full), page 3 (empty)
+	if callCount != 3 {
+		t.Errorf("expected 3 API calls, got %d", callCount)
+	}
+}
+
+func TestListReviews_MaxPagesCutoff(t *testing.T) {
+	// When maxPages is hit and the last page is full, results are truncated
+	// and a warning would fire (we verify the reviews are still returned).
+	const pageSize = 2
+	const maxPages = 2
+	callCount := 0
+
+	c := newTestClient(t, func(w http.ResponseWriter, r *http.Request) {
+		callCount++
+		page := r.URL.Query().Get("page")
+
+		// Always return a full page (simulating more data exists)
+		var reviews []map[string]interface{}
+		var baseID int
+		switch page {
+		case "1":
+			baseID = 0
+		case "2":
+			baseID = pageSize
+		default:
+			t.Fatalf("unexpected page %s (should not exceed maxPages)", page)
+		}
+		for i := 1; i <= pageSize; i++ {
+			reviews = append(reviews, map[string]interface{}{
+				"id": baseID + i, "body": fmt.Sprintf("r%d", baseID+i),
+				"state": "APPROVED", "commit_id": "sha1",
+				"user": map[string]string{"login": "user"},
+			})
+		}
+
+		json.NewEncoder(w).Encode(reviews)
+	})
+	c.SetReviewPagination(pageSize, maxPages)
+
+	reviews, err := c.ListReviews(context.Background(), "owner", "repo", 1)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	// Should return all reviews fetched within the cap
+	expectedCount := pageSize * maxPages
+	if len(reviews) != expectedCount {
+		t.Fatalf("expected %d reviews, got %d", expectedCount, len(reviews))
+	}
+	if callCount != maxPages {
+		t.Errorf("expected %d API calls, got %d", maxPages, callCount)
+	}
+	// Verify concatenation order
+	for i, r := range reviews {
+		if r.ID != int64(i+1) {
+			t.Errorf("review[%d]: expected ID %d, got %d", i, i+1, r.ID)
+		}
+	}
+}
+
+func TestListReviews_EmptyFirstPage(t *testing.T) {
+	// PR with no reviews: first page returns empty array.
+	callCount := 0
+	c := newTestClient(t, func(w http.ResponseWriter, r *http.Request) {
+		callCount++
+		json.NewEncoder(w).Encode([]map[string]interface{}{})
+	})
+	c.SetReviewPagination(10, 5)
+
+	reviews, err := c.ListReviews(context.Background(), "owner", "repo", 1)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if len(reviews) != 0 {
+		t.Fatalf("expected 0 reviews, got %d", len(reviews))
+	}
+	if callCount != 1 {
+		t.Errorf("expected 1 API call, got %d", callCount)
+	}
+}

github/reviews.go

@@ -0,0 +1,284 @@
+package github
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"log/slog"
+	"net/http"
+	"net/url"
+
+	"gitea.weiker.me/rodin/review-bot/vcs"
+)
+
+const (
+	// reviewsPerPage is the number of reviews to fetch per API page.
+	reviewsPerPage = 100
+	// maxReviewPages is the maximum number of pages to paginate through
+	// when listing reviews. Acts as a safeguard against infinite pagination.
+	maxReviewPages = 100
+)
+
+// ErrCannotDeleteSubmittedReview is returned when DeleteReview is called on
+// a review that has already been submitted (APPROVED, REQUEST_CHANGES, COMMENT).
+// GitHub only allows deletion of PENDING reviews. Callers that need to replace
+// a submitted review should use DismissReview instead.
+var ErrCannotDeleteSubmittedReview = errors.New("cannot delete submitted review: use DismissReview instead")
+
+// ErrConflictingCommitIDs is returned when PostReview receives comments with
+// differing non-empty CommitIDs. The GitHub API accepts only a single commit_id
+// per review submission; callers must ensure all comments target the same commit.
+var ErrConflictingCommitIDs = errors.New("comments contain conflicting commit IDs: all must target the same commit")
+
+// postReviewRequest is the GitHub API request body for creating a review.
+type postReviewRequest struct {
+	CommitID string               `json:"commit_id,omitempty"`
+	Body     string               `json:"body"`
+	Event    string               `json:"event"`
+	Comments []reviewCommentEntry `json:"comments,omitempty"`
+}
+
+// reviewCommentEntry is a single inline comment in a review creation request.
+type reviewCommentEntry struct {
+	Path     string `json:"path"`
+	Position int    `json:"position"`
+	Body     string `json:"body"`
+}
+
+// reviewResponse is the GitHub API response for a review.
+type reviewResponse struct {
+	ID       int64  `json:"id"`
+	Body     string `json:"body"`
+	State    string `json:"state"`
+	CommitID string `json:"commit_id"`
+	User     struct {
+		Login string `json:"login"`
+	} `json:"user"`
+}
+
+// dismissReviewRequest is the GitHub API request body for dismissing a review.
+type dismissReviewRequest struct {
+	Message string `json:"message"`
+	Event   string `json:"event"`
+}
+
+// userResponse is the GitHub API response for the authenticated user.
+type userResponse struct {
+	Login string `json:"login"`
+}
+
+// translateGitHubReviewState translates a GitHub API review state to the
+// canonical vcs.Review.State value.
+func translateGitHubReviewState(state string) string {
+	switch state {
+	case "CHANGES_REQUESTED":
+		return "REQUEST_CHANGES"
+	case "COMMENTED":
+		return "COMMENT"
+	default:
+		// States like APPROVED, DISMISSED, and PENDING pass through unchanged
+		// as they already match the canonical vcs representation. PENDING appears
+		// on draft reviews that have not yet been submitted via the GitHub UI or API.
+		return state
+	}
+}
+
+// PostReview submits a review on a pull request.
+//
+// The vcs.ReviewEvent constants (ReviewEventApprove, ReviewEventRequestChanges,
+// ReviewEventComment) have string values that match GitHub's wire-format event
+// strings (APPROVE, REQUEST_CHANGES, COMMENT), so Event is cast directly to
+// string without translation.
+//
+// ReviewComment.Position maps directly to the GitHub API position field.
+// When req.Comments is empty, the payload omits the comments field entirely
+// (via the omitempty tag on postReviewRequest.Comments).
+//
+// The GitHub API accepts a single commit_id per review submission. PostReview
+// uses req.CommitID as the primary commit anchor. If req.CommitID is empty,
+// it falls back to extracting from the first comment with a non-empty CommitID.
+// If any subsequent comment specifies a different CommitID, PostReview returns
+// ErrConflictingCommitIDs. Comments with an empty CommitID are allowed and
+// inherit the review-level value.
+func (c *Client) PostReview(ctx context.Context, owner, repo string, number int, req vcs.ReviewRequest) (*vcs.Review, error) {
+	reqURL := fmt.Sprintf("%s/repos/%s/%s/pulls/%d/reviews",
+		c.baseURL, url.PathEscape(owner), url.PathEscape(repo), number)
+
+	payload := postReviewRequest{
+		Body:     req.Body,
+		Event:    string(req.Event),
+		CommitID: req.CommitID,
+	}
+
+	// Build the payload in one pass. The GitHub API accepts a single commit_id
+	// per review. req.CommitID is the primary source; if empty, we extract from
+	// the first comment that supplies one. Reject if any comment disagrees with
+	// the resolved commit_id.
+	for _, comment := range req.Comments {
+		if comment.CommitID != "" {
+			if payload.CommitID == "" { // only reachable when req.CommitID is empty
+				payload.CommitID = comment.CommitID
+			} else if payload.CommitID != comment.CommitID {
+				return nil, ErrConflictingCommitIDs
+			}
+			// else: matching SHA is a no-op by design
+		}
+		payload.Comments = append(payload.Comments, reviewCommentEntry{
+			Path:     comment.Path,
+			Position: comment.Position,
+			Body:     comment.Body,
+		})
+	}
+
+	body, err := c.doJSONRequest(ctx, http.MethodPost, reqURL, payload)
+	if err != nil {
+		return nil, fmt.Errorf("post review: %w", err)
+	}
+
+	var resp reviewResponse
+	if err := json.Unmarshal(body, &resp); err != nil {
+		return nil, fmt.Errorf("parse review response: %w", err)
+	}
+
+	return &vcs.Review{
+		ID:       resp.ID,
+		Body:     resp.Body,
+		User:     vcs.UserInfo{Login: resp.User.Login},
+		State:    translateGitHubReviewState(resp.State),
+		CommitID: resp.CommitID,
+	}, nil
+}
+
+// ListReviews retrieves all reviews for a pull request with pagination.
+// GitHub review states are translated to canonical vcs values.
+func (c *Client) ListReviews(ctx context.Context, owner, repo string, number int) ([]vcs.Review, error) {
+	perPage := reviewsPerPage
+	if c.reviewPageSize > 0 {
+		perPage = c.reviewPageSize
+	}
+	maxPages := maxReviewPages
+	if c.reviewMaxPages > 0 {
+		maxPages = c.reviewMaxPages
+	}
+
+	var allReviews []vcs.Review
+	truncated := false
+
+	for page := 1; page <= maxPages; page++ {
+		reqURL := fmt.Sprintf("%s/repos/%s/%s/pulls/%d/reviews?per_page=%d&page=%d",
+			c.baseURL, url.PathEscape(owner), url.PathEscape(repo), number, perPage, page)
+
+		body, err := c.doGet(ctx, reqURL)
+		if err != nil {
+			return nil, fmt.Errorf("list reviews page %d: %w", page, err)
+		}
+
+		var responses []reviewResponse
+		if err := json.Unmarshal(body, &responses); err != nil {
+			return nil, fmt.Errorf("parse reviews response: %w", err)
+		}
+
+		if len(responses) == 0 {
+			break
+		}
+
+		for _, r := range responses {
+			allReviews = append(allReviews, vcs.Review{
+				ID:       r.ID,
+				Body:     r.Body,
+				User:     vcs.UserInfo{Login: r.User.Login},
+				State:    translateGitHubReviewState(r.State),
+				CommitID: r.CommitID,
+			})
+		}
+
+		if len(responses) < perPage {
+			break
+		}
+
+		// Truncation detection: this runs on the final allowed iteration
+		// (page == maxPages) only when the page was full (the len < perPage
+		// early-break above didn't fire). A full final page means additional
+		// reviews likely exist beyond our pagination limit.
+		if page == maxPages {
+			truncated = true
+		}
+	}
+
+	if truncated {
+		slog.Warn("ListReviews hit page limit; results may be truncated",
+			"owner", owner, "repo", repo, "pr", number,
+			"maxPages", maxPages, "reviewsFetched", len(allReviews))
+	}
+
+	return allReviews, nil
+}
+
+// DeleteReview deletes a pull request review.
+// Only PENDING reviews can be deleted; attempting to delete a submitted review
+// (APPROVED, CHANGES_REQUESTED, or COMMENTED per GitHub API naming) returns
+// ErrCannotDeleteSubmittedReview.
+func (c *Client) DeleteReview(ctx context.Context, owner, repo string, number int, reviewID int64) error {
+	reqURL := fmt.Sprintf("%s/repos/%s/%s/pulls/%d/reviews/%d",
+		c.baseURL, url.PathEscape(owner), url.PathEscape(repo), number, reviewID)
+
+	// nil body: the GitHub DELETE endpoint for reviews requires no request body.
+	_, err := c.doRequestWithBody(ctx, http.MethodDelete, reqURL, nil)
+	if err != nil {
+		var apiErr *APIError
+		if errors.As(err, &apiErr) && apiErr.StatusCode == 422 {
+			return fmt.Errorf("delete review: %w", ErrCannotDeleteSubmittedReview)
+		}
+		return fmt.Errorf("delete review: %w", err)
+	}
+	return nil
+}
+
+// DismissReview dismisses a submitted review on a pull request.
+// This is the correct way to "remove" a submitted review (APPROVED, REQUEST_CHANGES).
+// GitHub does not allow deleting submitted reviews — they must be dismissed.
+func (c *Client) DismissReview(ctx context.Context, owner, repo string, number int, reviewID int64, message string) error {
+	reqURL := fmt.Sprintf("%s/repos/%s/%s/pulls/%d/reviews/%d/dismissals",
+		c.baseURL, url.PathEscape(owner), url.PathEscape(repo), number, reviewID)
+
+	payload := dismissReviewRequest{
+		Message: message,
+		// Event is required by the GitHub API for dismissal requests, even though
+		// "DISMISS" is the only valid value for this endpoint.
+		Event: "DISMISS",
+	}
+
+	_, err := c.doJSONRequest(ctx, http.MethodPut, reqURL, payload)
+	if err != nil {
+		return fmt.Errorf("dismiss review: %w", err)
+	}
+	return nil
+}
+
+// SupersedeReviews marks prior reviews as superseded by dismissing them.
+// This implements vcs.ReviewSuperseder for the GitHub adapter.
+// The baseURL and sentinel parameters are unused for GitHub (dismissal is the mechanism).
+func (c *Client) SupersedeReviews(ctx context.Context, owner, repo string, prNumber int, oldReviews []vcs.Review, newReviewID int64, _, _ string) error {
+	var errs []error
+	for _, old := range oldReviews {
+		if err := c.DismissReview(ctx, owner, repo, prNumber, old.ID, "Superseded by new review"); err != nil {
+			errs = append(errs, fmt.Errorf("dismiss review %d: %w", old.ID, err))
+		}
+	}
+	return errors.Join(errs...)
+}
+
+// GetAuthenticatedUser returns the login name of the authenticated user.
+func (c *Client) GetAuthenticatedUser(ctx context.Context) (string, error) {
+	reqURL := fmt.Sprintf("%s/user", c.baseURL)
+	body, err := c.doGet(ctx, reqURL)
+	if err != nil {
+		return "", fmt.Errorf("get authenticated user: %w", err)
+	}
+	var resp userResponse
+	if err := json.Unmarshal(body, &resp); err != nil {
+		return "", fmt.Errorf("parse user response: %w", err)
+	}
+	return resp.Login, nil
+}

go.mod

@@ -1,3 +1,5 @@
 module gitea.weiker.me/rodin/review-bot
 
 go 1.26.2
+
+require gopkg.in/yaml.v3 v3.0.1

go.sum

@@ -0,0 +1,4 @@
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

integration_test.go

@@ -3,8 +3,10 @@
 package main
 
 import (
+	"context"
 	"os"
 	"strconv"
+	"strings"
 	"testing"
 
 	"gitea.weiker.me/rodin/review-bot/gitea"
@@ -42,28 +44,27 @@ func TestIntegration_FullReviewFlow(t *testing.T) {
 	}
 
 	// Parse owner/repo
-	owner, repoName := "", ""
-	for i, c := range giteaRepo {
-		if c == / {
-			owner = giteaRepo[:i]
-			repoName = giteaRepo[i+1:]
-			break
-		}
+	parts := strings.SplitN(giteaRepo, "/", 2)
+	if len(parts) != 2 {
+		t.Fatalf("Invalid repo format %q", giteaRepo)
 	}
+	owner, repoName := parts[0], parts[1]
 	if owner == "" || repoName == "" {
 		t.Fatalf("Invalid repo format %q", giteaRepo)
 	}
 
+	ctx := context.Background()
+
 	// Step 1: Fetch PR
 	giteaClient := gitea.NewClient(giteaURL, giteaToken)
-	pr, err := giteaClient.GetPullRequest(owner, repoName, prNumber)
+	pr, err := giteaClient.GetPullRequest(ctx, owner, repoName, prNumber)
 	if err != nil {
 		t.Fatalf("GetPullRequest: %v", err)
 	}
 	t.Logf("PR: %s (sha: %s)", pr.Title, pr.Head.Sha)
 
 	// Step 2: Fetch diff
-	diff, err := giteaClient.GetPullRequestDiff(owner, repoName, prNumber)
+	diff, err := giteaClient.GetPullRequestDiff(ctx, owner, repoName, prNumber)
 	if err != nil {
 		t.Fatalf("GetPullRequestDiff: %v", err)
 	}
@@ -73,12 +74,12 @@ func TestIntegration_FullReviewFlow(t *testing.T) {
 	t.Logf("Diff size: %d bytes", len(diff))
 
 	// Step 3: Build prompts
-	systemPrompt := review.BuildSystemPrompt("")
-	userPrompt := review.BuildUserPrompt(pr.Title, pr.Body, diff, true, "")
+	systemPrompt := review.BuildSystemPrompt("", "")
+	userPrompt := review.BuildUserPrompt(pr.Title, pr.Body, diff, "", true, "")
 
 	// Step 4: Call LLM
 	llmClient := llm.NewClient(llmBaseURL, llmAPIKey, llmModel)
-	response, err := llmClient.Complete([]llm.Message{
+	response, err := llmClient.Complete(ctx, []llm.Message{
 		{Role: "system", Content: systemPrompt},
 		{Role: "user", Content: userPrompt},
 	})

llm/aicore.go

@@ -0,0 +1,391 @@
+package llm
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"strings"
+	"sync"
+	"time"
+)
+
+// AICoreOpenAIAPIVersion is the API version used for OpenAI models through AI Core.
+// Update this when SAP AI Core releases a new stable version.
+const AICoreOpenAIAPIVersion = "2024-12-01-preview"
+
+// maxErrorBodyLen limits the length of response bodies included in error messages
+// to prevent leaking potentially sensitive upstream details in logs.
+const maxErrorBodyLen = 200
+
+// AICoreConfig holds SAP AI Core authentication and connection settings.
+type AICoreConfig struct {
+	ClientID      string
+	ClientSecret  string
+	AuthURL       string
+	APIURL        string
+	ResourceGroup string
+}
+
+// AICoreClient wraps AI Core authentication and deployment discovery.
+// Thread-safe for concurrent use after construction.
+//
+// Design: The deployment cache is populated once and never invalidated. This is
+// acceptable for short-lived CI runner processes, but longer-lived deployments
+// may want to add a TTL or re-fetch on errors.
+type AICoreClient struct {
+	config AICoreConfig
+	http   *http.Client
+
+	mu          sync.RWMutex
+	token       string
+	tokenExpiry time.Time
+	deployments map[string]string // model name -> deployment URL
+}
+
+// NewAICoreClient creates a new AI Core client with the given configuration.
+// The client uses a default 5-minute timeout; use WithTimeout to customize.
+func NewAICoreClient(cfg AICoreConfig) *AICoreClient {
+	return &AICoreClient{
+		config:      cfg,
+		http:        &http.Client{Timeout: 5 * time.Minute},
+		deployments: make(map[string]string),
+	}
+}
+
+// WithTimeout sets the HTTP request timeout for AI Core calls.
+// This should be called during construction, before concurrent use.
+func (c *AICoreClient) WithTimeout(d time.Duration) *AICoreClient {
+	c.http.Timeout = d
+	return c
+}
+
+// truncateBody truncates a response body for inclusion in error messages.
+// This prevents leaking potentially sensitive upstream response details in logs.
+func truncateBody(body []byte) string {
+	if len(body) <= maxErrorBodyLen {
+		return string(body)
+	}
+	return string(body[:maxErrorBodyLen]) + "..."
+}
+
+// getToken returns a valid OAuth token, refreshing if necessary.
+func (c *AICoreClient) getToken(ctx context.Context) (string, error) {
+	c.mu.RLock()
+	if c.token != "" && time.Now().Add(5*time.Minute).Before(c.tokenExpiry) {
+		token := c.token
+		c.mu.RUnlock()
+		return token, nil
+	}
+	c.mu.RUnlock()
+
+	c.mu.Lock()
+	defer c.mu.Unlock()
+
+	// Double-check after acquiring write lock
+	if c.token != "" && time.Now().Add(5*time.Minute).Before(c.tokenExpiry) {
+		return c.token, nil
+	}
+
+	token, expiry, err := c.fetchToken(ctx)
+	if err != nil {
+		return "", err
+	}
+	c.token = token
+	c.tokenExpiry = expiry
+	return token, nil
+}
+
+func (c *AICoreClient) fetchToken(ctx context.Context) (string, time.Time, error) {
+	tokenURL := strings.TrimRight(c.config.AuthURL, "/") + "/oauth/token"
+
+	data := url.Values{}
+	data.Set("grant_type", "client_credentials")
+	data.Set("client_id", c.config.ClientID)
+	data.Set("client_secret", c.config.ClientSecret)
+
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, tokenURL, strings.NewReader(data.Encode()))
+	if err != nil {
+		return "", time.Time{}, fmt.Errorf("create token request: %w", err)
+	}
+	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+
+	resp, err := c.http.Do(req)
+	if err != nil {
+		return "", time.Time{}, fmt.Errorf("token request: %w", err)
+	}
+	defer resp.Body.Close()
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return "", time.Time{}, fmt.Errorf("read token response: %w", err)
+	}
+
+	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
+		return "", time.Time{}, fmt.Errorf("token request failed (status %d): %s", resp.StatusCode, truncateBody(body))
+	}
+
+	var tokenResp struct {
+		AccessToken string `json:"access_token"`
+		ExpiresIn   int    `json:"expires_in"`
+	}
+	if err := json.Unmarshal(body, &tokenResp); err != nil {
+		return "", time.Time{}, fmt.Errorf("parse token response: %w", err)
+	}
+
+	if tokenResp.AccessToken == "" {
+		return "", time.Time{}, fmt.Errorf("empty access token in response")
+	}
+
+	expiry := time.Now().Add(time.Duration(tokenResp.ExpiresIn) * time.Second)
+	return tokenResp.AccessToken, expiry, nil
+}
+
+// getDeploymentURL returns the deployment URL for a model, fetching deployments if needed.
+// getDeploymentURL returns the deployment URL for a model, fetching deployments if needed.
+// Also returns a valid token for use by the caller, avoiding redundant getToken calls.
+//
+// Note: The token is fetched before acquiring the write lock to avoid holding the lock
+// during network I/O. In rare cases where multiple goroutines race and one waits a long
+// time for the write lock, the token could theoretically expire. The 5-minute refresh
+// buffer in getToken makes this extremely unlikely in practice.
+func (c *AICoreClient) getDeploymentURL(ctx context.Context, model string) (deployURL, token string, err error) {
+	c.mu.RLock()
+	if u, ok := c.deployments[model]; ok {
+		c.mu.RUnlock()
+		// Still need a token for the caller
+		token, err = c.getToken(ctx)
+		if err != nil {
+			return "", "", fmt.Errorf("get token: %w", err)
+		}
+		return u, token, nil
+	}
+	c.mu.RUnlock()
+
+	// Fetch token first (before acquiring write lock to avoid holding lock during I/O)
+	token, err = c.getToken(ctx)
+	if err != nil {
+		return "", "", fmt.Errorf("get token for deployments: %w", err)
+	}
+
+	c.mu.Lock()
+	defer c.mu.Unlock()
+
+	// Double-check after acquiring write lock
+	if u, ok := c.deployments[model]; ok {
+		return u, token, nil
+	}
+
+	if err := c.fetchDeployments(ctx, token); err != nil {
+		return "", "", err
+	}
+
+	if u, ok := c.deployments[model]; ok {
+		return u, token, nil
+	}
+	return "", "", fmt.Errorf("no deployment found for model %q", model)
+}
+
+func (c *AICoreClient) fetchDeployments(ctx context.Context, token string) error {
+	deployURL := strings.TrimRight(c.config.APIURL, "/") + "/v2/lm/deployments"
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, deployURL, nil)
+	if err != nil {
+		return fmt.Errorf("create deployments request: %w", err)
+	}
+	req.Header.Set("Authorization", "Bearer "+token)
+	req.Header.Set("AI-Resource-Group", c.config.ResourceGroup)
+
+	resp, err := c.http.Do(req)
+	if err != nil {
+		return fmt.Errorf("deployments request: %w", err)
+	}
+	defer resp.Body.Close()
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return fmt.Errorf("read deployments response: %w", err)
+	}
+
+	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
+		return fmt.Errorf("deployments request failed (status %d): %s", resp.StatusCode, truncateBody(body))
+	}
+
+	var deployResp struct {
+		Resources []struct {
+			DeploymentURL string `json:"deploymentUrl"`
+			Status        string `json:"status"`
+			Details       struct {
+				Resources struct {
+					BackendDetails struct {
+						Model struct {
+							Name string `json:"name"`
+						} `json:"model"`
+					} `json:"backend_details"`
+				} `json:"resources"`
+			} `json:"details"`
+		} `json:"resources"`
+	}
+	if err := json.Unmarshal(body, &deployResp); err != nil {
+		return fmt.Errorf("parse deployments response: %w", err)
+	}
+
+	for _, r := range deployResp.Resources {
+		if r.Status != "RUNNING" {
+			continue
+		}
+		modelName := r.Details.Resources.BackendDetails.Model.Name
+		if modelName == "" {
+			continue
+		}
+		c.deployments[modelName] = r.DeploymentURL
+	}
+
+	return nil
+}
+
+// CompleteAnthropic sends a request to an Anthropic model via AI Core.
+func (c *AICoreClient) CompleteAnthropic(ctx context.Context, model string, messages []Message, maxTokens int, temperature float64) (string, error) {
+	deployURL, token, err := c.getDeploymentURL(ctx, model)
+	if err != nil {
+		return "", err
+	}
+
+	// Extract system message
+	var system string
+	var userMessages []anthropicMsg
+	for _, m := range messages {
+		if m.Role == "system" {
+			system = m.Content
+		} else {
+			userMessages = append(userMessages, anthropicMsg{
+				Role:    m.Role,
+				Content: m.Content,
+			})
+		}
+	}
+
+	reqBody := anthropicRequest{
+		AnthropicVersion: "bedrock-2023-05-31", // SAP AI Core uses Bedrock format
+		// Model omitted - AI Core deployment already specifies model
+		MaxTokens: maxTokens,
+		System:    system,
+		Messages:  userMessages,
+	}
+	if temperature > 0 {
+		reqBody.Temperature = temperature
+	}
+
+	data, err := json.Marshal(reqBody)
+	if err != nil {
+		return "", fmt.Errorf("marshal request: %w", err)
+	}
+
+	// AI Core uses /invoke for Anthropic models
+	invokeURL := strings.TrimRight(deployURL, "/") + "/invoke"
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, invokeURL, bytes.NewReader(data))
+	if err != nil {
+		return "", fmt.Errorf("create request: %w", err)
+	}
+	req.Header.Set("Authorization", "Bearer "+token)
+	req.Header.Set("AI-Resource-Group", c.config.ResourceGroup)
+	req.Header.Set("Content-Type", "application/json")
+
+	resp, err := c.http.Do(req)
+	if err != nil {
+		return "", fmt.Errorf("AI Core request: %w", err)
+	}
+	defer resp.Body.Close()
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return "", fmt.Errorf("read response: %w", err)
+	}
+
+	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
+		return "", fmt.Errorf("AI Core API error (status %d): %s", resp.StatusCode, truncateBody(body))
+	}
+
+	var anthropicResp anthropicResponse
+	if err := json.Unmarshal(body, &anthropicResp); err != nil {
+		return "", fmt.Errorf("parse response: %w", err)
+	}
+
+	if len(anthropicResp.Content) == 0 {
+		return "", fmt.Errorf("no content in response")
+	}
+
+	var sb strings.Builder
+	for _, block := range anthropicResp.Content {
+		if block.Type == "text" {
+			sb.WriteString(block.Text)
+		}
+	}
+	result := sb.String()
+	if result == "" {
+		return "", fmt.Errorf("no text content in response")
+	}
+	return result, nil
+}
+
+// CompleteOpenAI sends a request to an OpenAI model via AI Core.
+func (c *AICoreClient) CompleteOpenAI(ctx context.Context, model string, messages []Message, temperature float64) (string, error) {
+	deployURL, token, err := c.getDeploymentURL(ctx, model)
+	if err != nil {
+		return "", err
+	}
+
+	reqBody := ChatRequest{
+		Model:       model,
+		Temperature: temperature,
+		Messages:    messages,
+	}
+
+	data, err := json.Marshal(reqBody)
+	if err != nil {
+		return "", fmt.Errorf("marshal request: %w", err)
+	}
+
+	// AI Core uses /chat/completions?api-version=<version> for OpenAI models
+	chatURL := strings.TrimRight(deployURL, "/") + "/chat/completions?api-version=" + AICoreOpenAIAPIVersion
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, chatURL, bytes.NewReader(data))
+	if err != nil {
+		return "", fmt.Errorf("create request: %w", err)
+	}
+	req.Header.Set("Authorization", "Bearer "+token)
+	req.Header.Set("AI-Resource-Group", c.config.ResourceGroup)
+	req.Header.Set("Content-Type", "application/json")
+
+	resp, err := c.http.Do(req)
+	if err != nil {
+		return "", fmt.Errorf("AI Core request: %w", err)
+	}
+	defer resp.Body.Close()
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return "", fmt.Errorf("read response: %w", err)
+	}
+
+	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
+		return "", fmt.Errorf("AI Core API error (status %d): %s", resp.StatusCode, truncateBody(body))
+	}
+
+	var openaiResp ChatResponse
+	if err := json.Unmarshal(body, &openaiResp); err != nil {
+		return "", fmt.Errorf("parse response: %w", err)
+	}
+
+	if len(openaiResp.Choices) == 0 {
+		return "", fmt.Errorf("no choices in response")
+	}
+	return openaiResp.Choices[0].Message.Content, nil
+}
+
+// IsAnthropicModel returns true if the model name indicates an Anthropic model.
+// SAP AI Core uses "anthropic--" prefix for Anthropic models (e.g., "anthropic--claude-3-5-sonnet").
+func IsAnthropicModel(model string) bool {
+	return strings.HasPrefix(model, "anthropic--")
+}

llm/aicore_test.go

@@ -0,0 +1,535 @@
+package llm
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"sync/atomic"
+	"testing"
+	"time"
+)
+
+func TestAICoreClient_TokenFetch(t *testing.T) {
+	tokenCalls := int32(0)
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path == "/oauth/token" {
+			atomic.AddInt32(&tokenCalls, 1)
+			if r.Method != http.MethodPost {
+				t.Errorf("expected POST for token, got %s", r.Method)
+			}
+			if r.Header.Get("Content-Type") != "application/x-www-form-urlencoded" {
+				t.Errorf("expected form content type")
+			}
+			w.Header().Set("Content-Type", "application/json")
+			json.NewEncoder(w).Encode(map[string]interface{}{
+				"access_token": "test-token-123",
+				"expires_in":   3600,
+			})
+			return
+		}
+		t.Errorf("unexpected path: %s", r.URL.Path)
+	}))
+	defer server.Close()
+
+	client := NewAICoreClient(AICoreConfig{
+		ClientID:      "test-id",
+		ClientSecret:  "test-secret",
+		AuthURL:       server.URL,
+		APIURL:        server.URL,
+		ResourceGroup: "default",
+	})
+
+	token, err := client.getToken(context.Background())
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if token != "test-token-123" {
+		t.Errorf("expected token 'test-token-123', got %q", token)
+	}
+
+	// Second call should use cached token
+	token2, err := client.getToken(context.Background())
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if token2 != "test-token-123" {
+		t.Errorf("expected cached token")
+	}
+	if atomic.LoadInt32(&tokenCalls) != 1 {
+		t.Errorf("expected 1 token call (cached), got %d", tokenCalls)
+	}
+}
+
+func TestAICoreClient_DeploymentFetch(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path == "/oauth/token" {
+			w.Header().Set("Content-Type", "application/json")
+			json.NewEncoder(w).Encode(map[string]interface{}{
+				"access_token": "test-token",
+				"expires_in":   3600,
+			})
+			return
+		}
+		if r.URL.Path == "/v2/lm/deployments" {
+			if r.Header.Get("Authorization") != "Bearer test-token" {
+				t.Errorf("expected Bearer auth")
+			}
+			if r.Header.Get("AI-Resource-Group") != "default" {
+				t.Errorf("expected resource group header")
+			}
+			w.Header().Set("Content-Type", "application/json")
+			json.NewEncoder(w).Encode(map[string]interface{}{
+				"resources": []map[string]interface{}{
+					{
+						"id":            "deploy-123",
+						"deploymentUrl": "https://example.com/v2/inference/deployments/deploy-123",
+						"status":        "RUNNING",
+						"details": map[string]interface{}{
+							"resources": map[string]interface{}{
+								"backend_details": map[string]interface{}{
+									"model": map[string]interface{}{
+										"name": "anthropic--claude-4.6-sonnet",
+									},
+								},
+							},
+						},
+					},
+					{
+						"id":            "deploy-456",
+						"deploymentUrl": "https://example.com/v2/inference/deployments/deploy-456",
+						"status":        "STOPPED",
+						"details": map[string]interface{}{
+							"resources": map[string]interface{}{
+								"backend_details": map[string]interface{}{
+									"model": map[string]interface{}{
+										"name": "gpt-5",
+									},
+								},
+							},
+						},
+					},
+					{
+						"id":            "deploy-789",
+						"deploymentUrl": "https://example.com/v2/inference/deployments/deploy-789",
+						"status":        "RUNNING",
+						"details": map[string]interface{}{
+							"resources": map[string]interface{}{
+								"backend_details": map[string]interface{}{
+									"model": map[string]interface{}{
+										"name": "gpt-5",
+									},
+								},
+							},
+						},
+					},
+				},
+			})
+			return
+		}
+		t.Errorf("unexpected path: %s", r.URL.Path)
+	}))
+	defer server.Close()
+
+	client := NewAICoreClient(AICoreConfig{
+		ClientID:      "test-id",
+		ClientSecret:  "test-secret",
+		AuthURL:       server.URL,
+		APIURL:        server.URL,
+		ResourceGroup: "default",
+	})
+
+	// Should find running deployment
+	url, _, err := client.getDeploymentURL(context.Background(), "anthropic--claude-4.6-sonnet")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if url != "https://example.com/v2/inference/deployments/deploy-123" {
+		t.Errorf("unexpected URL: %s", url)
+	}
+
+	// Should find running gpt-5, not stopped one
+	url, _, err = client.getDeploymentURL(context.Background(), "gpt-5")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if url != "https://example.com/v2/inference/deployments/deploy-789" {
+		t.Errorf("unexpected URL: %s", url)
+	}
+
+	// Should error on unknown model
+	_, _, err = client.getDeploymentURL(context.Background(), "unknown-model")
+	if err == nil {
+		t.Error("expected error for unknown model")
+	}
+}
+
+func TestAICoreClient_CompleteAnthropic(t *testing.T) {
+	// baseURL is set after server creation; captured by closure in handlers
+	var baseURL string
+	mux := http.NewServeMux()
+	mux.HandleFunc("/oauth/token", func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/json")
+		json.NewEncoder(w).Encode(map[string]interface{}{
+			"access_token": "test-token",
+			"expires_in":   3600,
+		})
+	})
+	mux.HandleFunc("/v2/lm/deployments", func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/json")
+		json.NewEncoder(w).Encode(map[string]interface{}{
+			"resources": []map[string]interface{}{
+				{
+					"id":            "deploy-anthropic",
+					"deploymentUrl": baseURL + "/deployments/anthropic",
+					"status":        "RUNNING",
+					"details": map[string]interface{}{
+						"resources": map[string]interface{}{
+							"backend_details": map[string]interface{}{
+								"model": map[string]interface{}{
+									"name": "anthropic--claude-4.6-sonnet",
+								},
+							},
+						},
+					},
+				},
+			},
+		})
+	})
+	mux.HandleFunc("/deployments/anthropic/invoke", func(w http.ResponseWriter, r *http.Request) {
+		if r.Header.Get("Authorization") != "Bearer test-token" {
+			t.Errorf("expected Bearer auth on invoke")
+		}
+		var req anthropicRequest
+		if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+			t.Fatalf("decode request: %v", err)
+		}
+		if req.AnthropicVersion != "bedrock-2023-05-31" {
+			t.Errorf("expected bedrock anthropic_version in request")
+		}
+		if req.System != "You are helpful" {
+			t.Errorf("expected system prompt: %q", req.System)
+		}
+		w.Header().Set("Content-Type", "application/json")
+		json.NewEncoder(w).Encode(map[string]interface{}{
+			"content": []map[string]interface{}{
+				{"type": "text", "text": "Hello from AI Core!"},
+			},
+		})
+	})
+
+	server := httptest.NewServer(mux)
+	baseURL = server.URL
+	defer server.Close()
+
+	client := NewAICoreClient(AICoreConfig{
+		ClientID:      "test-id",
+		ClientSecret:  "test-secret",
+		AuthURL:       server.URL,
+		APIURL:        server.URL,
+		ResourceGroup: "default",
+	})
+
+	result, err := client.CompleteAnthropic(context.Background(), "anthropic--claude-4.6-sonnet", []Message{
+		{Role: "system", Content: "You are helpful"},
+		{Role: "user", Content: "Hello"},
+	}, 8192, 0)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if result != "Hello from AI Core!" {
+		t.Errorf("expected 'Hello from AI Core!', got %q", result)
+	}
+}
+
+func TestAICoreClient_CompleteOpenAI(t *testing.T) {
+	var baseURL string
+	mux := http.NewServeMux()
+	mux.HandleFunc("/oauth/token", func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/json")
+		json.NewEncoder(w).Encode(map[string]interface{}{
+			"access_token": "test-token",
+			"expires_in":   3600,
+		})
+	})
+	mux.HandleFunc("/v2/lm/deployments", func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/json")
+		json.NewEncoder(w).Encode(map[string]interface{}{
+			"resources": []map[string]interface{}{
+				{
+					"id":            "deploy-openai",
+					"deploymentUrl": baseURL + "/deployments/openai",
+					"status":        "RUNNING",
+					"details": map[string]interface{}{
+						"resources": map[string]interface{}{
+							"backend_details": map[string]interface{}{
+								"model": map[string]interface{}{
+									"name": "gpt-5",
+								},
+							},
+						},
+					},
+				},
+			},
+		})
+	})
+	mux.HandleFunc("/deployments/openai/chat/completions", func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Query().Get("api-version") != AICoreOpenAIAPIVersion {
+			t.Errorf("expected api-version %s, got %s", AICoreOpenAIAPIVersion, r.URL.Query().Get("api-version"))
+		}
+		var req ChatRequest
+		if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+			t.Fatalf("decode request: %v", err)
+		}
+		if req.Model != "gpt-5" {
+			t.Errorf("expected model gpt-5, got %s", req.Model)
+		}
+		w.Header().Set("Content-Type", "application/json")
+		json.NewEncoder(w).Encode(ChatResponse{
+			Choices: []struct {
+				Message struct {
+					Content string `json:"content"`
+				} `json:"message"`
+			}{
+				{Message: struct {
+					Content string `json:"content"`
+				}{Content: "Hello from GPT-5!"}},
+			},
+		})
+	})
+
+	server := httptest.NewServer(mux)
+	baseURL = server.URL
+	defer server.Close()
+
+	client := NewAICoreClient(AICoreConfig{
+		ClientID:      "test-id",
+		ClientSecret:  "test-secret",
+		AuthURL:       server.URL,
+		APIURL:        server.URL,
+		ResourceGroup: "default",
+	})
+
+	result, err := client.CompleteOpenAI(context.Background(), "gpt-5", []Message{
+		{Role: "user", Content: "Hello"},
+	}, 0)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if result != "Hello from GPT-5!" {
+		t.Errorf("expected 'Hello from GPT-5!', got %q", result)
+	}
+}
+
+func TestIsAnthropicModel(t *testing.T) {
+	tests := []struct {
+		model    string
+		expected bool
+	}{
+		// SAP AI Core uses "anthropic--" prefix for Anthropic models
+		{"anthropic--claude-4.6-sonnet", true},
+		{"anthropic--claude-4.6-opus", true},
+		{"anthropic--claude-3-5-sonnet", true},
+		// Non-prefixed model names are not detected as Anthropic
+		// (SAP AI Core always uses the prefix for Anthropic models)
+		{"claude-sonnet-4", false},
+		{"gpt-5", false},
+		{"gpt-4.1", false},
+		{"llama-3", false},
+		{"my-claude-model", false}, // Avoid false positives on "claude" substring
+	}
+
+	for _, tt := range tests {
+		got := IsAnthropicModel(tt.model)
+		if got != tt.expected {
+			t.Errorf("IsAnthropicModel(%q) = %v, want %v", tt.model, got, tt.expected)
+		}
+	}
+}
+
+func TestAICoreClient_TokenExpiry(t *testing.T) {
+	tokenCalls := int32(0)
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path == "/oauth/token" {
+			call := atomic.AddInt32(&tokenCalls, 1)
+			w.Header().Set("Content-Type", "application/json")
+			json.NewEncoder(w).Encode(map[string]interface{}{
+				"access_token": fmt.Sprintf("token-%d", call),
+				"expires_in":   1, // 1 second expiry
+			})
+			return
+		}
+	}))
+	defer server.Close()
+
+	client := NewAICoreClient(AICoreConfig{
+		ClientID:      "test-id",
+		ClientSecret:  "test-secret",
+		AuthURL:       server.URL,
+		APIURL:        server.URL,
+		ResourceGroup: "default",
+	})
+
+	// First call
+	token1, err := client.getToken(context.Background())
+	if err != nil {
+		t.Fatalf("first getToken: %v", err)
+	}
+
+	// Force token expiry by manipulating expiry time
+	client.mu.Lock()
+	client.tokenExpiry = time.Now().Add(-time.Hour)
+	client.mu.Unlock()
+
+	// Should fetch new token
+	token2, err := client.getToken(context.Background())
+	if err != nil {
+		t.Fatalf("second getToken: %v", err)
+	}
+
+	if token1 == token2 {
+		t.Error("expected different tokens after expiry")
+	}
+	if atomic.LoadInt32(&tokenCalls) != 2 {
+		t.Errorf("expected 2 token calls, got %d", tokenCalls)
+	}
+}
+
+func TestAICoreClient_WithTimeout(t *testing.T) {
+	client := NewAICoreClient(AICoreConfig{
+		ClientID:      "test-id",
+		ClientSecret:  "test-secret",
+		AuthURL:       "https://auth.example.com",
+		APIURL:        "https://api.example.com",
+		ResourceGroup: "default",
+	})
+
+	// Default timeout is 5 minutes
+	if client.http.Timeout != 5*time.Minute {
+		t.Errorf("expected default timeout 5m, got %v", client.http.Timeout)
+	}
+
+	// WithTimeout should update the timeout
+	client.WithTimeout(10 * time.Minute)
+	if client.http.Timeout != 10*time.Minute {
+		t.Errorf("expected timeout 10m, got %v", client.http.Timeout)
+	}
+}
+
+func TestClient_WithAICore(t *testing.T) {
+	client := NewClient("http://example.com", "key", "model")
+	if client.provider != ProviderOpenAI {
+		t.Errorf("expected default provider openai, got %s", client.provider)
+	}
+
+	client.WithAICore(AICoreConfig{
+		ClientID:      "id",
+		ClientSecret:  "secret",
+		AuthURL:       "https://auth.example.com",
+		APIURL:        "https://api.example.com",
+		ResourceGroup: "default",
+	})
+
+	if client.provider != ProviderAICore {
+		t.Errorf("expected provider aicore, got %s", client.provider)
+	}
+	if client.aicore == nil {
+		t.Error("expected aicore client to be set")
+	}
+}
+
+func TestClient_WithTimeout_PropagatestoAICore(t *testing.T) {
+	client := NewClient("http://example.com", "key", "model").
+		WithAICore(AICoreConfig{
+			ClientID:      "id",
+			ClientSecret:  "secret",
+			AuthURL:       "https://auth.example.com",
+			APIURL:        "https://api.example.com",
+			ResourceGroup: "default",
+		})
+
+	// Default should be 5 minutes (inherited from parent client)
+	if client.aicore.http.Timeout != 5*time.Minute {
+		t.Errorf("expected aicore default timeout 5m, got %v", client.aicore.http.Timeout)
+	}
+
+	// WithTimeout should propagate to AI Core client
+	client.WithTimeout(15 * time.Minute)
+	if client.http.Timeout != 15*time.Minute {
+		t.Errorf("expected parent timeout 15m, got %v", client.http.Timeout)
+	}
+	if client.aicore.http.Timeout != 15*time.Minute {
+		t.Errorf("expected aicore timeout 15m, got %v", client.aicore.http.Timeout)
+	}
+}
+
+func TestClient_CompleteAICore(t *testing.T) {
+	var baseURL string
+	mux := http.NewServeMux()
+	mux.HandleFunc("/oauth/token", func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/json")
+		json.NewEncoder(w).Encode(map[string]interface{}{
+			"access_token": "test-token",
+			"expires_in":   3600,
+		})
+	})
+	mux.HandleFunc("/v2/lm/deployments", func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/json")
+		json.NewEncoder(w).Encode(map[string]interface{}{
+			"resources": []map[string]interface{}{
+				{
+					"id":            "deploy-test",
+					"deploymentUrl": baseURL + "/deployments/test",
+					"status":        "RUNNING",
+					"details": map[string]interface{}{
+						"resources": map[string]interface{}{
+							"backend_details": map[string]interface{}{
+								"model": map[string]interface{}{
+									"name": "gpt-5",
+								},
+							},
+						},
+					},
+				},
+			},
+		})
+	})
+	mux.HandleFunc("/deployments/test/chat/completions", func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/json")
+		json.NewEncoder(w).Encode(ChatResponse{
+			Choices: []struct {
+				Message struct {
+					Content string `json:"content"`
+				} `json:"message"`
+			}{
+				{Message: struct {
+					Content string `json:"content"`
+				}{Content: "AI Core via Client works!"}},
+			},
+		})
+	})
+
+	server := httptest.NewServer(mux)
+	baseURL = server.URL
+	defer server.Close()
+
+	client := NewClient("", "", "gpt-5").WithAICore(AICoreConfig{
+		ClientID:      "test-id",
+		ClientSecret:  "test-secret",
+		AuthURL:       server.URL,
+		APIURL:        server.URL,
+		ResourceGroup: "default",
+	})
+
+	result, err := client.Complete(context.Background(), []Message{
+		{Role: "user", Content: "Hello"},
+	})
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if !strings.Contains(result, "AI Core via Client works!") {
+		t.Errorf("unexpected result: %s", result)
+	}
+}

llm/client.go

@@ -1,36 +1,84 @@
+// Package llm provides clients for LLM chat completion APIs.
+//
+// Supports OpenAI-compatible (default), Anthropic Messages API, and SAP AI Core providers.
 package llm
 
 import (
 	"bytes"
+	"context"
 	"encoding/json"
 	"fmt"
 	"io"
 	"net/http"
 	"strings"
+	"time"
 )
 
-// Client calls an OpenAI-compatible chat completion API.
+// Provider identifies which API format to use.
+type Provider string
+
+const (
+	// ProviderOpenAI uses the OpenAI-compatible chat/completions endpoint.
+	ProviderOpenAI Provider = "openai"
+	// ProviderAnthropic uses the Anthropic Messages API endpoint.
+	ProviderAnthropic Provider = "anthropic"
+	// ProviderAICore uses SAP AI Core with OAuth authentication.
+	ProviderAICore Provider = "aicore"
+)
+
+// Client calls an LLM chat completion API.
+// A Client is safe for concurrent use by multiple goroutines after construction.
+// WithTimeout, WithTemperature, and WithProvider must be called during setup,
+// before concurrent use.
 type Client struct {
-	BaseURL string
-	APIKey  string
-	Model   string
-	Temperature float64
-	HTTP    *http.Client
+	baseURL     string
+	apiKey      string
+	model       string
+	temperature float64
+	provider    Provider
+	http        *http.Client
+	aicore      *AICoreClient // Only set when provider is aicore
 }
 
-// NewClient creates a new LLM client.
+// NewClient creates a new LLM client. Default provider is OpenAI-compatible.
 func NewClient(baseURL, apiKey, model string) *Client {
 	return &Client{
-		BaseURL: strings.TrimRight(baseURL, "/"),
-		APIKey:  apiKey,
-		Model:   model,
-		HTTP:    &http.Client{},
+		baseURL:  strings.TrimRight(baseURL, "/"),
+		apiKey:   apiKey,
+		model:    model,
+		provider: ProviderOpenAI,
+		http:     &http.Client{Timeout: 5 * time.Minute},
 	}
 }
 
+// WithTimeout sets the HTTP request timeout for LLM calls (default 5 minutes).
+// When using AI Core, this also sets the timeout on the AI Core client.
+func (c *Client) WithTimeout(d time.Duration) *Client {
+	c.http.Timeout = d
+	if c.aicore != nil {
+		c.aicore.WithTimeout(d)
+	}
+	return c
+}
+
 // WithTemperature sets the temperature for LLM requests (0 = omit, uses server default).
 func (c *Client) WithTemperature(t float64) *Client {
-	c.Temperature = t
+	c.temperature = t
+	return c
+}
+
+// WithProvider sets the API provider format (openai, anthropic, or aicore).
+func (c *Client) WithProvider(p Provider) *Client {
+	c.provider = p
+	return c
+}
+
+// WithAICore configures the client to use SAP AI Core for authentication.
+// This sets the provider to aicore automatically.
+// The AI Core client inherits the current HTTP timeout from this client.
+func (c *Client) WithAICore(cfg AICoreConfig) *Client {
+	c.provider = ProviderAICore
+	c.aicore = NewAICoreClient(cfg).WithTimeout(c.http.Timeout)
 	return c
 }
 
@@ -40,14 +88,81 @@ type Message struct {
 	Content string `json:"content"`
 }
 
-// ChatRequest is the request payload.
+// Complete sends a chat completion request and returns the assistant's response content.
+// The first message with role "system" is treated as the system prompt.
+func (c *Client) Complete(ctx context.Context, messages []Message) (string, error) {
+	var result string
+	var err error
+
+	for attempt := 0; attempt < 2; attempt++ {
+		switch c.provider {
+		case ProviderAnthropic:
+			result, err = c.completeAnthropic(ctx, messages)
+		case ProviderAICore:
+			result, err = c.completeAICore(ctx, messages)
+		default:
+			result, err = c.completeOpenAI(ctx, messages)
+		}
+
+		if err == nil {
+			return result, nil
+		}
+
+		// Only retry on response body read errors (transient network issues).
+		// Do not retry on context cancellation, status errors, or parse errors
+		// that indicate a structural API problem.
+		if !isRetryableError(err) {
+			return "", err
+		}
+
+		if attempt == 0 && ctx.Err() == nil {
+			// Brief pause before retry to allow transient issues to resolve.
+			time.Sleep(500 * time.Millisecond)
+		}
+	}
+
+	return "", err
+}
+
+// completeAICore routes to AI Core using the appropriate endpoint based on model type.
+func (c *Client) completeAICore(ctx context.Context, messages []Message) (string, error) {
+	if c.aicore == nil {
+		return "", fmt.Errorf("AI Core client not configured")
+	}
+
+	if IsAnthropicModel(c.model) {
+		return c.aicore.CompleteAnthropic(ctx, c.model, messages, 8192, c.temperature)
+	}
+	return c.aicore.CompleteOpenAI(ctx, c.model, messages, c.temperature)
+}
+
+// isRetryableError returns true for transient errors worth retrying.
+func isRetryableError(err error) bool {
+	if err == nil {
+		return false
+	}
+	s := err.Error()
+	// Body read failures (connection reset, truncation)
+	if strings.Contains(s, "read response") {
+		return true
+	}
+	// Unexpected body length (our content-length validation)
+	if strings.Contains(s, "body length mismatch") {
+		return true
+	}
+	return false
+}
+
+// --- OpenAI-compatible implementation ---
+
+// ChatRequest is the OpenAI request payload.
 type ChatRequest struct {
 	Model       string    `json:"model"`
 	Messages    []Message `json:"messages"`
 	Temperature float64   `json:"temperature,omitempty"`
 }
 
-// ChatResponse is the response from the API.
+// ChatResponse is the OpenAI response.
 type ChatResponse struct {
 	Choices []struct {
 		Message struct {
@@ -56,13 +171,11 @@ type ChatResponse struct {
 	} `json:"choices"`
 }
 
-// Complete sends a chat completion request and returns the assistant's response content.
-func (c *Client) Complete(messages []Message) (string, error) {
+func (c *Client) completeOpenAI(ctx context.Context, messages []Message) (string, error) {
 	reqBody := ChatRequest{
-		Model:       c.Model,
-		Temperature: c.Temperature,
+		Model:       c.model,
+		Temperature: c.temperature,
 		Messages:    messages,
-		
 	}
 
 	data, err := json.Marshal(reqBody)
@@ -70,38 +183,134 @@ func (c *Client) Complete(messages []Message) (string, error) {
 		return "", fmt.Errorf("marshal request: %w", err)
 	}
 
-	url := c.BaseURL + "/chat/completions"
-	req, err := http.NewRequest("POST", url, bytes.NewReader(data))
+	url := c.baseURL + "/chat/completions"
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, url, bytes.NewReader(data))
 	if err != nil {
 		return "", fmt.Errorf("create request: %w", err)
 	}
-	req.Header.Set("Authorization", "Bearer "+c.APIKey)
+	req.Header.Set("Authorization", "Bearer "+c.apiKey)
 	req.Header.Set("Content-Type", "application/json")
 
-	resp, err := c.HTTP.Do(req)
+	return c.doRequest(req, func(body []byte) (string, error) {
+		var resp ChatResponse
+		if err := json.Unmarshal(body, &resp); err != nil {
+			return "", fmt.Errorf("parse response: %w", err)
+		}
+		if len(resp.Choices) == 0 {
+			return "", fmt.Errorf("no choices in LLM response")
+		}
+		return resp.Choices[0].Message.Content, nil
+	})
+}
+
+// --- Anthropic Messages API implementation ---
+
+type anthropicRequest struct {
+	AnthropicVersion string         `json:"anthropic_version,omitempty"`
+	Model       string         `json:"model,omitempty"`
+	MaxTokens   int            `json:"max_tokens"`
+	System      string         `json:"system,omitempty"`
+	Messages    []anthropicMsg `json:"messages"`
+	Temperature float64        `json:"temperature,omitempty"`
+}
+
+type anthropicMsg struct {
+	Role    string `json:"role"`
+	Content string `json:"content"`
+}
+
+type anthropicResponse struct {
+	Content []struct {
+		Type string `json:"type"`
+		Text string `json:"text"`
+	} `json:"content"`
+}
+
+func (c *Client) completeAnthropic(ctx context.Context, messages []Message) (string, error) {
+	// Extract system message (first message with role "system")
+	var system string
+	var userMessages []anthropicMsg
+	for _, m := range messages {
+		if m.Role == "system" {
+			system = m.Content
+		} else {
+			userMessages = append(userMessages, anthropicMsg{
+				Role:    m.Role,
+				Content: m.Content,
+			})
+		}
+	}
+
+	reqBody := anthropicRequest{
+		Model:     c.model,
+		MaxTokens: 8192,
+		System:    system,
+		Messages:  userMessages,
+	}
+	if c.temperature > 0 {
+		reqBody.Temperature = c.temperature
+	}
+
+	data, err := json.Marshal(reqBody)
+	if err != nil {
+		return "", fmt.Errorf("marshal request: %w", err)
+	}
+
+	url := c.baseURL + "/messages"
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, url, bytes.NewReader(data))
+	if err != nil {
+		return "", fmt.Errorf("create request: %w", err)
+	}
+	req.Header.Set("x-api-key", c.apiKey)
+	req.Header.Set("anthropic-version", "2023-06-01")
+	req.Header.Set("Content-Type", "application/json")
+
+	return c.doRequest(req, func(body []byte) (string, error) {
+		var resp anthropicResponse
+		if err := json.Unmarshal(body, &resp); err != nil {
+			return "", fmt.Errorf("parse response: %w", err)
+		}
+		if len(resp.Content) == 0 {
+			return "", fmt.Errorf("no content in Anthropic response")
+		}
+		// Concatenate all text blocks
+		var sb strings.Builder
+		for _, block := range resp.Content {
+			if block.Type == "text" {
+				sb.WriteString(block.Text)
+			}
+		}
+		result := sb.String()
+		if result == "" {
+			return "", fmt.Errorf("no text content in Anthropic response")
+		}
+		return result, nil
+	})
+}
+
+// --- Shared HTTP execution ---
+
+func (c *Client) doRequest(req *http.Request, parse func([]byte) (string, error)) (string, error) {
+	resp, err := c.http.Do(req)
 	if err != nil {
 		return "", fmt.Errorf("LLM request: %w", err)
 	}
 	defer resp.Body.Close()
 
-	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
-		body, _ := io.ReadAll(resp.Body)
-		return "", fmt.Errorf("LLM API error (status %d): %s", resp.StatusCode, string(body))
-	}
-
 	body, err := io.ReadAll(resp.Body)
 	if err != nil {
 		return "", fmt.Errorf("read response: %w", err)
 	}
 
-	var chatResp ChatResponse
-	if err := json.Unmarshal(body, &chatResp); err != nil {
-		return "", fmt.Errorf("parse response: %w", err)
+	// Validate body length against Content-Length header when present.
+	// A mismatch indicates the response was truncated in transit.
+	if cl := resp.ContentLength; cl > 0 && int64(len(body)) < cl {
+		return "", fmt.Errorf("body length mismatch: Content-Length=%d, received=%d", cl, len(body))
 	}
 
-	if len(chatResp.Choices) == 0 {
-		return "", fmt.Errorf("no choices in LLM response")
+	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
+		return "", fmt.Errorf("LLM API error (status %d): %s", resp.StatusCode, string(body))
 	}
 
-	return chatResp.Choices[0].Message.Content, nil
+	return parse(body)
 }

llm/client_test.go

@@ -1,10 +1,13 @@
 package llm
 
 import (
+	"context"
 	"encoding/json"
+	"fmt"
 	"net/http"
 	"net/http/httptest"
 	"testing"
+	"time"
 )
 
 func TestComplete_Success(t *testing.T) {
@@ -51,7 +54,7 @@ func TestComplete_Success(t *testing.T) {
 	defer server.Close()
 
 	client := NewClient(server.URL, "test-key", "gpt-4")
-	got, err := client.Complete([]Message{{Role: "user", Content: "Hi"}})
+	got, err := client.Complete(context.Background(), []Message{{Role: "user", Content: "Hi"}})
 	if err != nil {
 		t.Fatalf("unexpected error: %v", err)
 	}
@@ -68,7 +71,7 @@ func TestComplete_APIError(t *testing.T) {
 	defer server.Close()
 
 	client := NewClient(server.URL, "test-key", "gpt-4")
-	_, err := client.Complete([]Message{{Role: "user", Content: "Hi"}})
+	_, err := client.Complete(context.Background(), []Message{{Role: "user", Content: "Hi"}})
 	if err == nil {
 		t.Fatal("expected error for 429, got nil")
 	}
@@ -82,7 +85,7 @@ func TestComplete_NoChoices(t *testing.T) {
 	defer server.Close()
 
 	client := NewClient(server.URL, "test-key", "gpt-4")
-	_, err := client.Complete([]Message{{Role: "user", Content: "Hi"}})
+	_, err := client.Complete(context.Background(), []Message{{Role: "user", Content: "Hi"}})
 	if err == nil {
 		t.Fatal("expected error for no choices, got nil")
 	}
@@ -95,7 +98,7 @@ func TestComplete_BadJSON(t *testing.T) {
 	defer server.Close()
 
 	client := NewClient(server.URL, "test-key", "gpt-4")
-	_, err := client.Complete([]Message{{Role: "user", Content: "Hi"}})
+	_, err := client.Complete(context.Background(), []Message{{Role: "user", Content: "Hi"}})
 	if err == nil {
 		t.Fatal("expected error for bad JSON, got nil")
 	}
@@ -103,7 +106,7 @@ func TestComplete_BadJSON(t *testing.T) {
 
 func TestComplete_ServerDown(t *testing.T) {
 	client := NewClient("http://127.0.0.1:1", "test-key", "gpt-4")
-	_, err := client.Complete([]Message{{Role: "user", Content: "Hi"}})
+	_, err := client.Complete(context.Background(), []Message{{Role: "user", Content: "Hi"}})
 	if err == nil {
 		t.Fatal("expected error for connection refused, got nil")
 	}
@@ -111,16 +114,16 @@ func TestComplete_ServerDown(t *testing.T) {
 
 func TestWithTemperature(t *testing.T) {
 	client := NewClient("http://example.com", "key", "model")
-	if client.Temperature != 0 {
-		t.Errorf("expected initial temperature 0, got %f", client.Temperature)
+	if client.temperature != 0 {
+		t.Errorf("expected initial temperature 0, got %f", client.temperature)
 	}
 
 	result := client.WithTemperature(0.7)
 	if result != client {
 		t.Error("WithTemperature should return the same client for chaining")
 	}
-	if client.Temperature != 0.7 {
-		t.Errorf("expected temperature 0.7, got %f", client.Temperature)
+	if client.temperature != 0.7 {
+		t.Errorf("expected temperature 0.7, got %f", client.temperature)
 	}
 }
 
@@ -147,7 +150,7 @@ func TestComplete_TemperatureOmittedWhenZero(t *testing.T) {
 	defer server.Close()
 
 	client := NewClient(server.URL, "key", "model")
-	_, err := client.Complete([]Message{{Role: "user", Content: "Hi"}})
+	_, err := client.Complete(context.Background(), []Message{{Role: "user", Content: "Hi"}})
 	if err != nil {
 		t.Fatalf("unexpected error: %v", err)
 	}
@@ -180,8 +183,244 @@ func TestComplete_TemperatureIncludedWhenSet(t *testing.T) {
 	defer server.Close()
 
 	client := NewClient(server.URL, "key", "model").WithTemperature(0.7)
-	_, err := client.Complete([]Message{{Role: "user", Content: "Hi"}})
+	_, err := client.Complete(context.Background(), []Message{{Role: "user", Content: "Hi"}})
 	if err != nil {
 		t.Fatalf("unexpected error: %v", err)
 	}
 }
+
+func TestWithTimeout(t *testing.T) {
+	client := NewClient("http://example.com", "key", "model")
+	result := client.WithTimeout(10 * time.Second)
+	if result != client {
+		t.Error("WithTimeout should return the same client for chaining")
+	}
+	// Verify timeout causes failure on slow server
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		time.Sleep(200 * time.Millisecond)
+		w.Header().Set("Content-Type", "application/json")
+		w.Write([]byte(`{"choices":[{"message":{"content":"ok"}}]}`))
+	}))
+	defer server.Close()
+
+	shortClient := NewClient(server.URL, "key", "model").WithTimeout(50 * time.Millisecond)
+	_, err := shortClient.Complete(context.Background(), []Message{{Role: "user", Content: "hi"}})
+	if err == nil {
+		t.Error("expected timeout error with 50ms timeout and 200ms server delay")
+	}
+}
+
+
+func TestComplete_Anthropic_Success(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path != "/messages" {
+			t.Errorf("unexpected path: %s", r.URL.Path)
+		}
+		if r.Header.Get("x-api-key") != "test-key" {
+			t.Errorf("expected x-api-key header, got %q", r.Header.Get("x-api-key"))
+		}
+		if r.Header.Get("anthropic-version") != "2023-06-01" {
+			t.Errorf("expected anthropic-version header, got %q", r.Header.Get("anthropic-version"))
+		}
+
+		var req map[string]interface{}
+		json.NewDecoder(r.Body).Decode(&req)
+
+		if req["system"] != "You are helpful" {
+			t.Errorf("expected system prompt, got %v", req["system"])
+		}
+		msgs := req["messages"].([]interface{})
+		if len(msgs) != 1 {
+			t.Errorf("expected 1 user message, got %d", len(msgs))
+		}
+		if req["max_tokens"] != float64(8192) {
+			t.Errorf("expected max_tokens 8192, got %v", req["max_tokens"])
+		}
+
+		w.Header().Set("Content-Type", "application/json")
+		w.Write([]byte(`{"content":[{"type":"text","text":"Hello from Claude!"}]}`))
+	}))
+	defer server.Close()
+
+	client := NewClient(server.URL, "test-key", "claude-sonnet").WithProvider(ProviderAnthropic)
+	got, err := client.Complete(context.Background(), []Message{
+		{Role: "system", Content: "You are helpful"},
+		{Role: "user", Content: "Hi"},
+	})
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if got != "Hello from Claude!" {
+		t.Errorf("expected %q, got %q", "Hello from Claude!", got)
+	}
+}
+
+func TestComplete_Anthropic_NoContent(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/json")
+		w.Write([]byte(`{"content":[]}`))
+	}))
+	defer server.Close()
+
+	client := NewClient(server.URL, "test-key", "claude-sonnet").WithProvider(ProviderAnthropic)
+	_, err := client.Complete(context.Background(), []Message{{Role: "user", Content: "Hi"}})
+	if err == nil {
+		t.Fatal("expected error for empty content, got nil")
+	}
+}
+
+func TestComplete_Anthropic_APIError(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusBadRequest)
+		w.Write([]byte(`{"error":{"message":"invalid request"}}`))
+	}))
+	defer server.Close()
+
+	client := NewClient(server.URL, "test-key", "claude-sonnet").WithProvider(ProviderAnthropic)
+	_, err := client.Complete(context.Background(), []Message{{Role: "user", Content: "Hi"}})
+	if err == nil {
+		t.Fatal("expected error for 400, got nil")
+	}
+}
+
+func TestWithProvider(t *testing.T) {
+	client := NewClient("http://example.com", "key", "model")
+	if client.provider != ProviderOpenAI {
+		t.Errorf("expected default provider openai, got %s", client.provider)
+	}
+	result := client.WithProvider(ProviderAnthropic)
+	if result != client {
+		t.Error("WithProvider should return the same client for chaining")
+	}
+	if client.provider != ProviderAnthropic {
+		t.Errorf("expected provider anthropic, got %s", client.provider)
+	}
+}
+
+func TestComplete_RetryOnBodyReadError(t *testing.T) {
+	attempts := 0
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		attempts++
+		if attempts == 1 {
+			// First attempt: send headers then close connection abruptly
+			// Simulate by writing partial response and flushing with wrong Content-Length
+			w.Header().Set("Content-Length", "1000")
+			w.WriteHeader(http.StatusOK)
+			w.Write([]byte(`{"choices":[{"message":{"con`))
+			// The test HTTP server will close the connection after handler returns,
+			// but Content-Length mismatch means client gets fewer bytes than expected
+			return
+		}
+		// Second attempt: succeed
+		w.Header().Set("Content-Type", "application/json")
+		json.NewEncoder(w).Encode(ChatResponse{
+			Choices: []struct {
+				Message struct {
+					Content string `json:"content"`
+				} `json:"message"`
+			}{{Message: struct {
+				Content string `json:"content"`
+			}{Content: "success"}}},
+		})
+	}))
+	defer server.Close()
+
+	client := NewClient(server.URL, "key", "model")
+	got, err := client.Complete(context.Background(), []Message{{Role: "user", Content: "Hi"}})
+	if err != nil {
+		t.Fatalf("expected retry to succeed, got error: %v", err)
+	}
+	if got != "success" {
+		t.Errorf("expected %q, got %q", "success", got)
+	}
+	if attempts != 2 {
+		t.Errorf("expected 2 attempts, got %d", attempts)
+	}
+}
+
+func TestComplete_ContentLengthMismatch(t *testing.T) {
+	attempts := 0
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		attempts++
+		if attempts == 1 {
+			// Claim Content-Length is larger than actual body
+			w.Header().Set("Content-Length", "500")
+			w.Header().Set("Content-Type", "application/json")
+			w.WriteHeader(http.StatusOK)
+			// Write less than 500 bytes
+			w.Write([]byte(`{"choices":[{"message":{"content":"partial"}}]}`))
+			return
+		}
+		// Second attempt succeeds
+		w.Header().Set("Content-Type", "application/json")
+		json.NewEncoder(w).Encode(ChatResponse{
+			Choices: []struct {
+				Message struct {
+					Content string `json:"content"`
+				} `json:"message"`
+			}{{Message: struct {
+				Content string `json:"content"`
+			}{Content: "complete"}}},
+		})
+	}))
+	defer server.Close()
+
+	client := NewClient(server.URL, "key", "model")
+	got, err := client.Complete(context.Background(), []Message{{Role: "user", Content: "Hi"}})
+	if err != nil {
+		t.Fatalf("expected retry to succeed on content-length mismatch, got: %v", err)
+	}
+	if got != "complete" {
+		t.Errorf("expected %q, got %q", "complete", got)
+	}
+}
+
+func TestComplete_NoRetryOnAPIError(t *testing.T) {
+	attempts := 0
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		attempts++
+		w.WriteHeader(http.StatusBadRequest)
+		w.Write([]byte(`{"error":"bad request"}`))
+	}))
+	defer server.Close()
+
+	client := NewClient(server.URL, "key", "model")
+	_, err := client.Complete(context.Background(), []Message{{Role: "user", Content: "Hi"}})
+	if err == nil {
+		t.Fatal("expected error for 400, got nil")
+	}
+	if attempts != 1 {
+		t.Errorf("should not retry on API errors, got %d attempts", attempts)
+	}
+}
+
+func TestIsRetryableError(t *testing.T) {
+	tests := []struct {
+		name     string
+		err      string
+		expected bool
+	}{
+		{"nil formatted", "", false},
+		{"read response error", "read response: unexpected EOF", true},
+		{"body length mismatch", "body length mismatch: Content-Length=1000, received=500", true},
+		{"API error", "LLM API error (status 400): bad request", false},
+		{"parse error", "parse response: unexpected end of JSON input", false},
+		{"request error", "LLM request: connection refused", false},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if tt.err == "" {
+				if isRetryableError(nil) {
+					t.Error("nil error should not be retryable")
+				}
+				return
+			}
+			err := fmt.Errorf("%s", tt.err)
+			got := isRetryableError(err)
+			if got != tt.expected {
+				t.Errorf("isRetryableError(%q) = %v, want %v", tt.err, got, tt.expected)
+			}
+		})
+	}
+}

review/formatter.go

@@ -7,8 +7,28 @@ import (
 
 // FormatMarkdown formats a ReviewResult into the markdown body for a Gitea review.
 func FormatMarkdown(result *ReviewResult, reviewerName string) string {
+	return FormatMarkdownWithDisplay(result, reviewerName, reviewerName)
+}
+
+// FormatMarkdownWithDisplay formats a ReviewResult with separate display name and sentinel name.
+// Note: displayName is not HTML-escaped as Gitea sanitizes rendered Markdown.
+// Persona display names are controlled by repo owners (trusted input).
+// displayName is used for the header title, sentinelName is used for the cleanup sentinel.
+// If displayName is empty, sentinelName is used for both.
+func FormatMarkdownWithDisplay(result *ReviewResult, displayName, sentinelName string) string {
 	var sb strings.Builder
 
+	// Use display name for header, or fall back to sentinel name
+	headerName := displayName
+	if headerName == "" {
+		headerName = sentinelName
+	}
+
+	if headerName != "" {
+		title := CapitalizeFirst(headerName)
+		sb.WriteString(fmt.Sprintf("# %s Review\n\n", title))
+	}
+
 	sb.WriteString("## Summary\n\n")
 	sb.WriteString(result.Summary)
 	sb.WriteString("\n\n")
@@ -28,21 +48,11 @@ func FormatMarkdown(result *ReviewResult, reviewerName string) string {
 	sb.WriteString("## Recommendation\n\n")
 	sb.WriteString(fmt.Sprintf("**%s** — %s\n", result.Verdict, result.Recommendation))
 
-	if reviewerName != "" {
-		sb.WriteString(fmt.Sprintf("\n---\n*Review by %s*\n", reviewerName))
+	if sentinelName != "" {
+		sb.WriteString(fmt.Sprintf("\n---\n*Review by %s*\n", headerName))
+		// Hidden sentinel for identifying this bot's reviews during cleanup
+		sb.WriteString(fmt.Sprintf("\n<!-- review-bot:%s -->\n", sentinelName))
 	}
 
 	return sb.String()
 }
-
-// GiteaEvent converts the verdict to the Gitea API event string.
-func GiteaEvent(verdict string) string {
-	switch verdict {
-	case "APPROVE":
-		return "APPROVED"
-	case "REQUEST_CHANGES":
-		return "REQUEST_CHANGES"
-	default:
-		return "COMMENT"
-	}
-}

review/formatter_test.go

@@ -98,21 +98,100 @@ func TestFormatMarkdown_SpecialChars(t *testing.T) {
 	}
 }
 
-func TestGiteaEvent(t *testing.T) {
-	tests := []struct {
-		verdict  string
-		expected string
-	}{
-		{"APPROVE", "APPROVED"},
-		{"REQUEST_CHANGES", "REQUEST_CHANGES"},
-		{"UNKNOWN", "COMMENT"},
-		{"", "COMMENT"},
+func TestFormatMarkdown_Sentinel(t *testing.T) {
+	result := &ReviewResult{
+		Verdict:        "APPROVE",
+		Summary:        "All good.",
+		Recommendation: "Merge it.",
+	}
+	output := FormatMarkdown(result, "security")
+	if !strings.Contains(output, "<!-- review-bot:security -->") {
+		t.Error("expected sentinel comment in output")
 	}
 
-	for _, tc := range tests {
-		got := GiteaEvent(tc.verdict)
-		if got != tc.expected {
-			t.Errorf("GiteaEvent(%q) = %q, want %q", tc.verdict, got, tc.expected)
-		}
+	// Empty reviewer name should NOT have sentinel
+	output2 := FormatMarkdown(result, "")
+	if strings.Contains(output2, "<!-- review-bot") {
+		t.Error("should not contain sentinel when reviewer name is empty")
 	}
 }
+
+func TestFormatMarkdown_RoleTitle(t *testing.T) {
+	result := &ReviewResult{
+		Verdict:        "APPROVE",
+		Summary:        "All good.",
+		Recommendation: "Merge it.",
+	}
+
+	// With reviewer name: should have title header
+	output := FormatMarkdown(result, "security")
+	if !strings.Contains(output, "# Security Review\n") {
+		t.Error("expected '# Security Review' header when reviewer name is set")
+	}
+
+	output2 := FormatMarkdown(result, "gpt")
+	if !strings.Contains(output2, "# Gpt Review\n") {
+		t.Error("expected '# Gpt Review' header")
+	}
+
+	// Without reviewer name: no title header
+	output3 := FormatMarkdown(result, "")
+	if strings.Contains(output3, "# ") && strings.Contains(output3, " Review\n") {
+		t.Error("should not contain role title header when reviewer name is empty")
+	}
+}
+
+func TestFormatMarkdownWithDisplay(t *testing.T) {
+	result := &ReviewResult{
+		Verdict:        "APPROVE",
+		Summary:        "Test summary",
+		Findings:       nil,
+		Recommendation: "Test recommendation",
+	}
+
+	t.Run("with display name", func(t *testing.T) {
+		body := FormatMarkdownWithDisplay(result, "Security Specialist", "security")
+
+		// Header should use display name
+		if !strings.Contains(body, "# Security Specialist Review") {
+			t.Error("header should use display name")
+		}
+
+		// Sentinel should use sentinel name
+		if !strings.Contains(body, "<!-- review-bot:security -->") {
+			t.Error("sentinel should use sentinel name")
+		}
+
+		// Footer "Review by" should use display name
+		if !strings.Contains(body, "*Review by Security Specialist*") {
+			t.Error("footer should use display name")
+		}
+	})
+
+	t.Run("without display name", func(t *testing.T) {
+		body := FormatMarkdownWithDisplay(result, "", "reviewer")
+
+		// Should fall back to sentinel name for header
+		if !strings.Contains(body, "# Reviewer Review") {
+			t.Error("header should fall back to sentinel name")
+		}
+
+		if !strings.Contains(body, "<!-- review-bot:reviewer -->") {
+			t.Error("sentinel should use sentinel name")
+		}
+	})
+
+	t.Run("empty both names", func(t *testing.T) {
+		body := FormatMarkdownWithDisplay(result, "", "")
+
+		// Should not have header
+		if strings.Contains(body, "# ") && strings.Contains(body, " Review") {
+			t.Error("should not have header when both names empty")
+		}
+
+		// Should not have sentinel
+		if strings.Contains(body, "<!-- review-bot:") {
+			t.Error("should not have sentinel when sentinel name empty")
+		}
+	})
+}

review/parser.go

@@ -29,7 +29,19 @@ func ParseResponse(response string) (*ReviewResult, error) {
 
 	var result ReviewResult
 	if err := json.Unmarshal([]byte(cleaned), &result); err != nil {
-		return nil, fmt.Errorf("parse LLM response as JSON: %w\nRaw response: %s", err, response)
+		// LLMs sometimes produce JSON with unescaped quotes inside string values.
+		// Try to repair before giving up.
+		repaired := repairJSON(cleaned)
+		if err2 := json.Unmarshal([]byte(repaired), &result); err2 != nil {
+			// Include diagnostic info: lengths help identify truncation
+			rawLen := len(response)
+			cleanedLen := len(cleaned)
+			preview := cleaned
+			if len(preview) > 200 {
+				preview = preview[:100] + "..." + preview[len(preview)-100:]
+			}
+			return nil, fmt.Errorf("parse LLM response as JSON: %w\nRaw length: %d, cleaned length: %d\nCleaned preview: %s", err, rawLen, cleanedLen, preview)
+		}
 	}
 
 	// Validate verdict
@@ -74,3 +86,230 @@ func extractJSON(s string) string {
 	s = strings.TrimSpace(s)
 	return s
 }
+
+// repairJSON attempts to fix common LLM JSON issues:
+// - Unescaped double quotes inside string values
+//
+// Strategy: walk the JSON structurally. Object keys are parsed normally (LLMs
+// get those right). For string VALUES, we find all candidate closing quotes and
+// pick the LAST one that leaves valid JSON structure afterward — maximizing
+// string content, which is the correct bias for the "LLM put unescaped quotes
+// in a string value" failure mode.
+func repairJSON(s string) string {
+	runes := []rune(s)
+	var out strings.Builder
+	out.Grow(len(s) + 64)
+
+	i := 0
+	for i < len(runes) {
+		c := runes[i]
+
+		if c != '"' {
+			out.WriteRune(c)
+			i++
+			continue
+		}
+
+		// We hit an opening quote. Determine if this is a key or a value.
+		// Keys: the standard JSON parser in LLMs gets keys right, so we parse
+		// them normally (first unescaped quote closes).
+		// Values: may contain unescaped quotes — use the repair heuristic.
+		isValue := isValuePosition(runes, i)
+
+		if !isValue {
+			// Parse key/simple string normally
+			out.WriteRune('"')
+			i++
+			for i < len(runes) {
+				ch := runes[i]
+				if ch == '\\' && i+1 < len(runes) {
+					out.WriteRune(ch)
+					i++
+					out.WriteRune(runes[i])
+					i++
+					continue
+				}
+				if ch == '"' {
+					out.WriteRune('"')
+					i++
+					break
+				}
+				out.WriteRune(ch)
+				i++
+			}
+			continue
+		}
+
+		// Value string — find the correct close using last-valid-candidate heuristic
+		out.WriteRune('"')
+		i++
+
+		closeIdx := findClosingQuote(runes, i)
+
+		// Write everything between open and close, escaping interior quotes
+		for j := i; j < closeIdx; j++ {
+			ch := runes[j]
+			if ch == '\\' && j+1 < closeIdx {
+				// Already-escaped sequence — pass through
+				out.WriteRune(ch)
+				j++
+				out.WriteRune(runes[j])
+			} else if ch == '"' {
+				out.WriteRune('\\')
+				out.WriteRune('"')
+			} else {
+				out.WriteRune(ch)
+			}
+		}
+
+		// Write the closing quote
+		out.WriteRune('"')
+		i = closeIdx + 1
+	}
+
+	return out.String()
+}
+
+// isValuePosition determines if the quote at position i is opening a JSON value
+// string (as opposed to an object key). We only apply repair to values that
+// follow ':' since those are the free-text fields where LLMs produce unescaped
+// quotes. Array elements and keys are left alone (parsed normally).
+func isValuePosition(runes []rune, i int) bool {
+	// Look backward, skipping whitespace, for the preceding structural char
+	j := i - 1
+	for j >= 0 && (runes[j] == ' ' || runes[j] == '\t' || runes[j] == '\n' || runes[j] == '\r') {
+		j--
+	}
+	if j < 0 {
+		return false
+	}
+	// After ':' → definitely a value
+	return runes[j] == ':'
+}
+
+// findClosingQuote finds the index of the true closing quote for a JSON string
+// value starting at position start (the character after the opening quote).
+// It collects all unescaped quote candidates and returns the FIRST one that
+// produces valid JSON continuation (deeper lookahead verifies the next token).
+func findClosingQuote(runes []rune, start int) int {
+	// Collect all candidate positions for the closing quote.
+	var candidates []int
+	for j := start; j < len(runes); j++ {
+		if runes[j] == '\\' {
+			j++ // skip escaped character
+			continue
+		}
+		if runes[j] == '"' {
+			candidates = append(candidates, j)
+		}
+	}
+
+	if len(candidates) == 0 {
+		return len(runes)
+	}
+
+	if len(candidates) == 1 {
+		return candidates[0]
+	}
+
+	// Try candidates from FIRST to LAST. The correct closing quote is the
+	// earliest one that produces valid JSON structure after it (verified by
+	// deeper lookahead that checks the next token is a valid JSON start).
+	for _, idx := range candidates {
+		if isValidJSONAfterClose(runes, idx+1) {
+			return idx
+		}
+	}
+
+	// Fallback: return the last candidate
+	return candidates[len(candidates)-1]
+}
+
+// isValidJSONAfterClose checks whether the runes after a candidate closing quote
+// look like valid JSON continuation for a VALUE string. Since we only use this
+// for value positions, ':' is NOT a valid continuation (values are never keys).
+// Checks deeper structure to avoid being fooled by JSON-like content in strings.
+func isValidJSONAfterClose(runes []rune, pos int) bool {
+	j := pos
+	for j < len(runes) && (runes[j] == ' ' || runes[j] == '\t' || runes[j] == '\n' || runes[j] == '\r') {
+		j++
+	}
+
+	if j >= len(runes) {
+		return true
+	}
+
+	next := runes[j]
+	if next == '}' || next == ']' {
+		// Closing a container. Verify what follows the close is also valid:
+		// another structural char, comma, or EOF.
+		return isValidAfterContainerClose(runes, j+1)
+	}
+	if next == ',' {
+		// After comma, must be followed by a valid JSON token
+		j++
+		for j < len(runes) && (runes[j] == ' ' || runes[j] == '\t' || runes[j] == '\n' || runes[j] == '\r') {
+			j++
+		}
+		if j >= len(runes) {
+			return false // trailing comma with nothing after — invalid
+		}
+		return isJSONTokenStart(runes, j)
+	}
+	// ':' is NOT valid here — we're in a value position, not a key.
+	// Any other character is also invalid.
+	return false
+}
+
+// isValidAfterContainerClose checks that after a } or ], the continuation is
+// structurally valid: more closes, comma+token, or EOF.
+func isValidAfterContainerClose(runes []rune, pos int) bool {
+	j := pos
+	for j < len(runes) && (runes[j] == ' ' || runes[j] == '\t' || runes[j] == '\n' || runes[j] == '\r') {
+		j++
+	}
+	if j >= len(runes) {
+		return true
+	}
+	next := runes[j]
+	if next == '}' || next == ']' {
+		return isValidAfterContainerClose(runes, j+1)
+	}
+	if next == ',' {
+		j++
+		for j < len(runes) && (runes[j] == ' ' || runes[j] == '\t' || runes[j] == '\n' || runes[j] == '\r') {
+			j++
+		}
+		if j >= len(runes) {
+			return false
+		}
+		return isJSONTokenStart(runes, j)
+	}
+	return false
+}
+
+// isJSONTokenStart returns true if the rune could begin a JSON value or key.
+// For keywords (true/false/null), verifies the full keyword is present.
+func isJSONTokenStart(runes []rune, pos int) bool {
+	if pos >= len(runes) {
+		return false
+	}
+	r := runes[pos]
+	switch {
+	case r == '"': // string
+		return true
+	case r == '{' || r == '[': // object or array
+		return true
+	case r == 't': // true
+		return pos+4 <= len(runes) && string(runes[pos:pos+4]) == "true"
+	case r == 'f': // false
+		return pos+5 <= len(runes) && string(runes[pos:pos+5]) == "false"
+	case r == 'n': // null
+		return pos+4 <= len(runes) && string(runes[pos:pos+4]) == "null"
+	case r >= '0' && r <= '9': // number
+		return true
+	case r == '-': // negative number
+		return true
+	}
+	return false
+}

review/parser_test.go

@@ -1,6 +1,7 @@
 package review
 
 import (
+	"encoding/json"
 	"testing"
 )
 
@@ -112,3 +113,112 @@ func TestParseResponse_MarkdownFencesNoLang(t *testing.T) {
 		t.Errorf("expected APPROVE, got %q", result.Verdict)
 	}
 }
+
+func TestParseResponse_UnescapedQuotesInStrings(t *testing.T) {
+	// Real failure from CI: Sonnet puts unescaped quotes like (e.g. "28") in findings
+	input := `{"verdict": "APPROVE", "summary": "Clean PR", "findings": [{"severity": "NIT", "file": "ci/Dockerfile", "line": 14, "finding": "The comment says OTP_VERSION is the major version (e.g. \"28\") but it actually contains unescaped quotes like (e.g. "28") which breaks JSON"}], "recommendation": "Ship it"}`
+
+	result, err := ParseResponse(input)
+	if err != nil {
+		t.Fatalf("expected repair to handle unescaped quotes, got error: %v", err)
+	}
+	if result.Verdict != "APPROVE" {
+		t.Errorf("expected APPROVE, got %q", result.Verdict)
+	}
+	if len(result.Findings) != 1 {
+		t.Fatalf("expected 1 finding, got %d", len(result.Findings))
+	}
+}
+
+func TestRepairJSON_NoOpOnValid(t *testing.T) {
+	valid := `{"key": "value", "num": 42}`
+	result := repairJSON(valid)
+	if result != valid {
+		t.Errorf("repairJSON should not modify valid JSON\n  got:  %s\n  want: %s", result, valid)
+	}
+}
+
+func TestRepairJSON_FixesUnescapedQuotes(t *testing.T) {
+	// Interior quote followed by non-structural character
+	input := `{"msg": "use "foo" here"}`
+	result := repairJSON(input)
+
+	// Should be parseable now
+	var m map[string]interface{}
+	if err := json.Unmarshal([]byte(result), &m); err != nil {
+		t.Fatalf("repaired JSON should parse, got: %v\nrepaired: %s", err, result)
+	}
+}
+
+func TestRepairJSON_InteriorQuoteBeforeComma(t *testing.T) {
+	// Bug reported by reviewer: interior quoted word immediately before a comma
+	input := `{"msg": "say "yes", and go"}`
+	result := repairJSON(input)
+
+	var m map[string]interface{}
+	if err := json.Unmarshal([]byte(result), &m); err != nil {
+		t.Fatalf("repaired JSON should parse, got: %v\nrepaired: %s", err, result)
+	}
+	// The full string content should be preserved
+	msg, ok := m["msg"].(string)
+	if !ok {
+		t.Fatal("msg field missing or not a string")
+	}
+	if msg != `say "yes", and go` {
+		t.Errorf("unexpected msg content: %q", msg)
+	}
+}
+
+func TestRepairJSON_InteriorQuoteBeforeCloseBrace(t *testing.T) {
+	// Bug reported by reviewer: JSON-shaped syntax inside string values
+	input := `{"msg": "input map {"key": "val"} caused error"}`
+	result := repairJSON(input)
+
+	var m map[string]interface{}
+	if err := json.Unmarshal([]byte(result), &m); err != nil {
+		t.Fatalf("repaired JSON should parse, got: %v\nrepaired: %s", err, result)
+	}
+}
+
+func TestRepairJSON_MultipleFields(t *testing.T) {
+	// Multiple string fields with unescaped quotes in different positions
+	input := `{"a": "hello "world"", "b": "foo"}`
+	result := repairJSON(input)
+
+	var m map[string]interface{}
+	if err := json.Unmarshal([]byte(result), &m); err != nil {
+		t.Fatalf("repaired JSON should parse, got: %v\nrepaired: %s", err, result)
+	}
+	if _, ok := m["b"]; !ok {
+		t.Error("expected 'b' field to be preserved")
+	}
+}
+
+func TestRepairJSON_PreservesEscapedQuotes(t *testing.T) {
+	// Already-escaped quotes should not be double-escaped
+	input := `{"msg": "already \"escaped\" here"}`
+	result := repairJSON(input)
+
+	if result != input {
+		t.Errorf("repairJSON should not modify already-escaped quotes\n  got:  %s\n  want: %s", result, input)
+	}
+
+	var m map[string]interface{}
+	if err := json.Unmarshal([]byte(result), &m); err != nil {
+		t.Fatalf("repaired JSON should parse, got: %v\nrepaired: %s", err, result)
+	}
+}
+
+func TestRepairJSON_ComplexNestedContent(t *testing.T) {
+	// Combines both reviewer bugs: quoted words before commas AND JSON-like content
+	input := `{"verdict": "APPROVE", "findings": [{"finding": "The map {"key": "val"} and (e.g. "28") and say "yes", then stop"}]}`
+	result := repairJSON(input)
+
+	var parsed map[string]interface{}
+	if err := json.Unmarshal([]byte(result), &parsed); err != nil {
+		t.Fatalf("repaired JSON should parse, got: %v\nrepaired: %s", err, result)
+	}
+	if parsed["verdict"] != "APPROVE" {
+		t.Errorf("expected verdict APPROVE, got %v", parsed["verdict"])
+	}
+}

review/persona.go

@@ -0,0 +1,259 @@
+package review
+
+import (
+	"bytes"
+	"embed"
+	"encoding/json"
+	"fmt"
+	"os"
+	"sort"
+	"strings"
+	"unicode/utf8"
+
+	"gopkg.in/yaml.v3"
+)
+
+//go:embed personas/*.yaml
+var embeddedPersonas embed.FS
+
+// MaxPersonaFileSize is the maximum size for persona files (64 KB).
+// This prevents denial-of-service via excessively large files.
+const MaxPersonaFileSize = 64 * 1024
+
+// MaxYAMLDepth is the maximum nesting depth allowed in YAML persona files.
+// This prevents stack exhaustion from deeply nested structures.
+const MaxYAMLDepth = 20
+
+// MaxYAMLNodes is the maximum number of YAML nodes allowed in persona files.
+// This prevents DoS via wide-but-shallow structures that bypass depth limits.
+const MaxYAMLNodes = 1000
+
+// Persona defines a specialized review role with focused expertise.
+type Persona struct {
+	Name         string   `json:"name" yaml:"name"`
+	DisplayName  string   `json:"display_name" yaml:"display_name"`
+	ModelPref    string   `json:"model_preference,omitempty" yaml:"model_preference,omitempty"`
+	Identity     string   `json:"identity" yaml:"identity"`
+	Focus        []string `json:"focus" yaml:"focus"`
+	Ignore       []string `json:"ignore" yaml:"ignore"`
+	Severity     Severity `json:"severity" yaml:"severity"`
+	OutputFormat string   `json:"output_format,omitempty" yaml:"output_format,omitempty"`
+}
+
+// Severity defines what constitutes each severity level for this persona.
+// These are prompt guidance for the LLM, not output format changes.
+type Severity struct {
+	Major string `json:"major" yaml:"major"`
+	Minor string `json:"minor" yaml:"minor"`
+	Nit   string `json:"nit" yaml:"nit"`
+}
+
+// LoadPersona loads a persona from a JSON or YAML file path.
+// Format is detected by file extension: .yaml/.yml for YAML, .json or other for JSON.
+// Files larger than MaxPersonaFileSize are rejected.
+//
+// Symlinks are supported: os.Stat follows symlinks, so a symlink pointing to
+// a regular file will pass the IsRegular() check. Symlinks to non-regular files
+// (directories, FIFOs, devices) are still rejected.
+func LoadPersona(path string) (*Persona, error) {
+	// os.Stat follows symlinks, so symlinks to regular files are supported.
+	// The IsRegular() check operates on the target, not the symlink itself.
+	info, err := os.Stat(path)
+	if err != nil {
+		return nil, fmt.Errorf("read persona file %s: %w", path, err)
+	}
+	if !info.Mode().IsRegular() {
+		return nil, fmt.Errorf("persona file %s is not a regular file", path)
+	}
+	if info.Size() > MaxPersonaFileSize {
+		return nil, fmt.Errorf("persona file %s exceeds maximum size (%d bytes)", path, MaxPersonaFileSize)
+	}
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return nil, fmt.Errorf("read persona file %s: %w", path, err)
+	}
+	// Re-check size after read to defend against TOCTOU races where file
+	// grows between stat and read (e.g., appending process, replaced file).
+	if len(data) > MaxPersonaFileSize {
+		return nil, fmt.Errorf("persona file %s exceeds maximum size (%d bytes)", path, MaxPersonaFileSize)
+	}
+	return parsePersona(data, path)
+}
+
+// LoadBuiltinPersona loads a built-in persona by name.
+// Returns an error if the persona doesn't exist.
+// Built-in personas are stored in YAML format only (see embed directive).
+func LoadBuiltinPersona(name string) (*Persona, error) {
+	yamlFile := name + ".yaml"
+	data, err := embeddedPersonas.ReadFile("personas/" + yamlFile)
+	if err != nil {
+		available := ListBuiltinPersonas()
+		return nil, fmt.Errorf("unknown built-in persona %q (available: %s)", name, strings.Join(available, ", "))
+	}
+	return parsePersona(data, "builtin:"+yamlFile)
+}
+
+// ListBuiltinPersonas returns the names of all built-in personas in sorted order.
+// Returns an empty slice if the embedded directory cannot be read.
+func ListBuiltinPersonas() []string {
+	entries, err := embeddedPersonas.ReadDir("personas")
+	if err != nil {
+		return []string{}
+	}
+	seen := make(map[string]bool)
+	for _, e := range entries {
+		if e.IsDir() {
+			continue
+		}
+		name := e.Name()
+		// Strip extension to get persona name
+		var personaName string
+		switch {
+		case strings.HasSuffix(name, ".yaml"):
+			personaName = strings.TrimSuffix(name, ".yaml")
+		case strings.HasSuffix(name, ".yml"):
+			personaName = strings.TrimSuffix(name, ".yml")
+		case strings.HasSuffix(name, ".json"):
+			personaName = strings.TrimSuffix(name, ".json")
+		default:
+			continue
+		}
+		if !seen[personaName] {
+			seen[personaName] = true
+		}
+	}
+	names := make([]string, 0, len(seen))
+	for name := range seen {
+		names = append(names, name)
+	}
+	sort.Strings(names)
+	return names
+}
+
+// parsePersona parses persona data from JSON or YAML format.
+// Format is detected by the source file extension.
+func parsePersona(data []byte, source string) (*Persona, error) {
+	lowerSource := strings.ToLower(source)
+	isYAML := strings.HasSuffix(lowerSource, ".yaml") || strings.HasSuffix(lowerSource, ".yml")
+
+	var p Persona
+	var err error
+	if isYAML {
+		err = unmarshalYAMLWithDepthLimit(data, &p, MaxYAMLDepth)
+	} else {
+		// Use json.Decoder with DisallowUnknownFields for consistency with
+		// YAML's KnownFields(true) - both reject unknown fields to catch typos.
+		dec := json.NewDecoder(bytes.NewReader(data))
+		dec.DisallowUnknownFields()
+		err = dec.Decode(&p)
+	}
+	if err != nil {
+		return nil, fmt.Errorf("parse persona %s: %w", source, err)
+	}
+	if err := validatePersona(&p, source); err != nil {
+		return nil, err
+	}
+	return &p, nil
+}
+
+// unmarshalYAMLWithDepthLimit unmarshals YAML data with explicit depth limiting
+// and strict field checking. This protects against stack exhaustion from deeply
+// nested structures and catches typos in field names.
+// Multi-document YAML files are rejected to prevent silent data loss.
+func unmarshalYAMLWithDepthLimit(data []byte, out any, maxDepth int) error {
+	// First pass: decode into a yaml.Node to check depth limits and node counts.
+	// This prevents stack exhaustion before we attempt to decode into structs.
+	var node yaml.Node
+	dec := yaml.NewDecoder(bytes.NewReader(data))
+	if err := dec.Decode(&node); err != nil {
+		return err
+	}
+
+	// Reject multi-document YAML files - silently ignoring additional documents
+	// could lead to confusing behavior where users think their changes take effect.
+	var extra yaml.Node
+	if dec.Decode(&extra) == nil {
+		return fmt.Errorf("multi-document YAML is not supported; only single-document files are allowed")
+	}
+
+	nodeCount := 0
+	if err := checkYAMLDepth(&node, 0, maxDepth, MaxYAMLNodes, make(map[*yaml.Node]struct{}), &nodeCount); err != nil {
+		return err
+	}
+
+	// Second pass: decode with strict field checking enabled.
+	// KnownFields(true) rejects unknown keys, catching typos like "focuss" or "identiy".
+	// We must re-decode from the original data because yaml.Node.Decode() doesn't
+	// support the KnownFields option.
+	strictDec := yaml.NewDecoder(bytes.NewReader(data))
+	strictDec.KnownFields(true)
+	return strictDec.Decode(out)
+}
+
+// checkYAMLDepth recursively checks that YAML nodes don't exceed the depth limit
+// or the total node count limit. It also detects alias cycles to prevent infinite
+// recursion from crafted YAML with self-referential aliases.
+func checkYAMLDepth(node *yaml.Node, depth, maxDepth, maxNodes int, seen map[*yaml.Node]struct{}, nodeCount *int) error {
+	if depth > maxDepth {
+		return fmt.Errorf("YAML nesting depth exceeds maximum (%d)", maxDepth)
+	}
+
+	// Track total nodes visited as defense-in-depth against wide-but-shallow attacks.
+	*nodeCount++
+	if *nodeCount > maxNodes {
+		return fmt.Errorf("YAML node count exceeds maximum (%d)", maxNodes)
+	}
+
+	// Cycle detection: if we've seen this node before, we're in a cycle.
+	if _, ok := seen[node]; ok {
+		return nil // Already validated this subtree, skip to avoid infinite recursion.
+	}
+	seen[node] = struct{}{}
+
+	// Handle alias nodes: follow the alias to its anchor target.
+	// Increment depth when following aliases since they expand the effective structure.
+	if node.Kind == yaml.AliasNode && node.Alias != nil {
+		return checkYAMLDepth(node.Alias, depth+1, maxDepth, maxNodes, seen, nodeCount)
+	}
+
+	for _, child := range node.Content {
+		if err := checkYAMLDepth(child, depth+1, maxDepth, maxNodes, seen, nodeCount); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// ParsePersonaBytes parses persona data from bytes with a source label for errors.
+// This is useful for parsing personas fetched from external sources (e.g., Gitea API)
+// without requiring filesystem access. Format is detected by source extension.
+func ParsePersonaBytes(data []byte, source string) (*Persona, error) {
+	return parsePersona(data, source)
+}
+
+func validatePersona(p *Persona, source string) error {
+	if p.Name == "" {
+		return fmt.Errorf("persona %s: name is required", source)
+	}
+	if p.Identity == "" {
+		return fmt.Errorf("persona %s: identity is required", source)
+	}
+	// DisplayName defaults to Name if not set
+	if p.DisplayName == "" {
+		p.DisplayName = p.Name
+	}
+	return nil
+}
+
+// CapitalizeFirst capitalizes the first rune of a string in a Unicode-safe way.
+// Returns the original string if it's empty.
+func CapitalizeFirst(s string) string {
+	if s == "" {
+		return s
+	}
+	r, size := utf8.DecodeRuneInString(s)
+	if r == utf8.RuneError {
+		return s
+	}
+	return strings.ToUpper(string(r)) + s[size:]
+}

review/persona_prompt.go

@@ -0,0 +1,104 @@
+package review
+
+import (
+	"fmt"
+	"strings"
+)
+
+// BuildPersonaSystemPrompt constructs a system prompt from a persona definition.
+// This replaces BuildSystemBase when a persona is provided.
+func BuildPersonaSystemPrompt(p *Persona) string {
+	var sb strings.Builder
+
+	// Identity section
+	sb.WriteString(p.Identity)
+	sb.WriteString("\n\n")
+
+	// Focus section
+	if len(p.Focus) > 0 {
+		sb.WriteString("## Focus Areas\n\n")
+		sb.WriteString("Concentrate your review on:\n")
+		for _, f := range p.Focus {
+			sb.WriteString(fmt.Sprintf("- %s\n", f))
+		}
+		sb.WriteString("\n")
+	}
+
+	// Ignore section
+	if len(p.Ignore) > 0 {
+		sb.WriteString("## Explicitly Out of Scope\n\n")
+		sb.WriteString("Do NOT comment on:\n")
+		for _, i := range p.Ignore {
+			sb.WriteString(fmt.Sprintf("- %s\n", i))
+		}
+		sb.WriteString("\n")
+	}
+
+	// Severity calibration
+	if p.Severity.Major != "" || p.Severity.Minor != "" || p.Severity.Nit != "" {
+		sb.WriteString("## Severity Calibration\n\n")
+		sb.WriteString("Use these severity definitions for YOUR domain:\n")
+		if p.Severity.Major != "" {
+			sb.WriteString(fmt.Sprintf("- **MAJOR**: %s\n", p.Severity.Major))
+		}
+		if p.Severity.Minor != "" {
+			sb.WriteString(fmt.Sprintf("- **MINOR**: %s\n", p.Severity.Minor))
+		}
+		if p.Severity.Nit != "" {
+			sb.WriteString(fmt.Sprintf("- **NIT**: %s\n", p.Severity.Nit))
+		}
+		sb.WriteString("\n")
+	}
+
+	// Output format instructions (shared schema from prompt.go)
+	sb.WriteString("## Review Instructions\n\n")
+	sb.WriteString("CONTEXT:\n")
+	sb.WriteString("- You will receive the full content of modified files for reference, followed by the diff showing what changed.\n")
+	sb.WriteString("- The diff shows ONLY what was added/removed. The full file content provides complete context.\n")
+	sb.WriteString("- Focus your review on the CHANGES (the diff), using the full files for context.\n\n")
+	sb.WriteString("Your task:\n")
+	sb.WriteString("1. Review the diff for issues within YOUR focus areas only.\n")
+	sb.WriteString("2. Consider the CI status — if CI has failed, that is an automatic REQUEST_CHANGES regardless of code quality.\n")
+	sb.WriteString("3. Output your review as structured JSON (and ONLY JSON, no markdown fences or other text).\n\n")
+	sb.WriteString("Output format:\n")
+	sb.WriteString(outputSchemaJSON)
+	sb.WriteString("\n\n")
+	sb.WriteString(verdictRules)
+	sb.WriteString("\n- Only report findings within your focus areas. Ignore everything else.\n")
+	sb.WriteString("- Line numbers should reference the new file line numbers from the diff headers.\n")
+	sb.WriteString("- If the diff has no changes relevant to your focus areas, APPROVE with no findings.\n")
+
+	// Custom output format if provided
+	if p.OutputFormat != "" {
+		sb.WriteString("\n\n## Additional Output Guidelines\n\n")
+		sb.WriteString(p.OutputFormat)
+	}
+
+	return sb.String()
+}
+
+// BuildSystemPromptWithPersona constructs the full system prompt, using either
+// a persona or the default generic prompt. This is a convenience wrapper that
+// combines BuildPersonaSystemPrompt (or BuildSystemBase) with patterns and conventions.
+// It is exported for use by callers who want one-shot prompt assembly.
+func BuildSystemPromptWithPersona(persona *Persona, conventions, patterns string) string {
+	var base string
+	if persona != nil {
+		base = BuildPersonaSystemPrompt(persona)
+	} else {
+		base = BuildSystemBase()
+	}
+
+	var sb strings.Builder
+	sb.WriteString(base)
+
+	if patterns != "" {
+		sb.WriteString(fmt.Sprintf("\n\n## Language Patterns & Idioms\n\nUse the following patterns as review criteria. Code that violates these established patterns is a finding:\n\n%s\n", patterns))
+	}
+
+	if conventions != "" {
+		sb.WriteString(fmt.Sprintf("\n\n## Repository Conventions\n\nThe repository has the following coding conventions that must be respected:\n\n%s\n", conventions))
+	}
+
+	return sb.String()
+}

review/persona_prompt_test.go

@@ -0,0 +1,157 @@
+package review
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestBuildPersonaSystemPrompt(t *testing.T) {
+	p := &Persona{
+		Name:        "security",
+		DisplayName: "Security Specialist",
+		Identity:    "You are a security specialist.",
+		Focus:       []string{"injection attacks", "auth bypass"},
+		Ignore:      []string{"code style", "performance"},
+		Severity: Severity{
+			Major: "exploitable vulnerabilities",
+			Minor: "defense in depth",
+			Nit:   "theoretical risks",
+		},
+	}
+
+	prompt := BuildPersonaSystemPrompt(p)
+
+	// Check identity is included
+	if !strings.Contains(prompt, "You are a security specialist.") {
+		t.Error("prompt should contain identity")
+	}
+
+	// Check focus areas
+	if !strings.Contains(prompt, "Focus Areas") {
+		t.Error("prompt should contain Focus Areas section")
+	}
+	if !strings.Contains(prompt, "injection attacks") {
+		t.Error("prompt should contain focus item")
+	}
+
+	// Check ignore section
+	if !strings.Contains(prompt, "Out of Scope") {
+		t.Error("prompt should contain Out of Scope section")
+	}
+	if !strings.Contains(prompt, "code style") {
+		t.Error("prompt should contain ignore item")
+	}
+
+	// Check severity calibration
+	if !strings.Contains(prompt, "Severity Calibration") {
+		t.Error("prompt should contain Severity Calibration section")
+	}
+	if !strings.Contains(prompt, "exploitable vulnerabilities") {
+		t.Error("prompt should contain major severity definition")
+	}
+
+	// Check JSON output format is included
+	if !strings.Contains(prompt, `"verdict"`) {
+		t.Error("prompt should contain JSON output format")
+	}
+	if !strings.Contains(prompt, "APPROVE") {
+		t.Error("prompt should mention APPROVE verdict")
+	}
+}
+
+func TestBuildPersonaSystemPromptMinimal(t *testing.T) {
+	// Minimal persona with only required fields
+	p := &Persona{
+		Name:     "minimal",
+		Identity: "You are a minimal reviewer.",
+	}
+
+	prompt := BuildPersonaSystemPrompt(p)
+
+	// Should still work without optional fields
+	if !strings.Contains(prompt, "You are a minimal reviewer.") {
+		t.Error("prompt should contain identity")
+	}
+
+	// Should not have empty sections
+	if strings.Contains(prompt, "Focus Areas") && !strings.Contains(prompt, "Concentrate your review on:") {
+		t.Error("should not have Focus Areas header without content")
+	}
+}
+
+func TestBuildSystemPromptWithPersona(t *testing.T) {
+	t.Run("with persona", func(t *testing.T) {
+		p := &Persona{
+			Name:     "test",
+			Identity: "Test persona identity.",
+			Focus:    []string{"testing"},
+		}
+
+		prompt := BuildSystemPromptWithPersona(p, "test conventions", "test patterns")
+
+		if !strings.Contains(prompt, "Test persona identity.") {
+			t.Error("should contain persona identity")
+		}
+		if !strings.Contains(prompt, "test conventions") {
+			t.Error("should contain conventions")
+		}
+		if !strings.Contains(prompt, "test patterns") {
+			t.Error("should contain patterns")
+		}
+	})
+
+	t.Run("without persona", func(t *testing.T) {
+		prompt := BuildSystemPromptWithPersona(nil, "test conventions", "test patterns")
+
+		// Should use default system base
+		if !strings.Contains(prompt, "expert code reviewer") {
+			t.Error("should contain default system base when no persona")
+		}
+		if !strings.Contains(prompt, "test conventions") {
+			t.Error("should contain conventions")
+		}
+	})
+
+	t.Run("empty conventions and patterns", func(t *testing.T) {
+		p := &Persona{
+			Name:     "test",
+			Identity: "Test identity.",
+		}
+
+		prompt := BuildSystemPromptWithPersona(p, "", "")
+
+		if strings.Contains(prompt, "Language Patterns") {
+			t.Error("should not contain patterns section when empty")
+		}
+		if strings.Contains(prompt, "Repository Conventions") {
+			t.Error("should not contain conventions section when empty")
+		}
+	})
+}
+
+func TestPersonaPromptContainsOutputRules(t *testing.T) {
+	p := &Persona{
+		Name:     "test",
+		Identity: "Test.",
+	}
+
+	prompt := BuildPersonaSystemPrompt(p)
+
+	// Must contain the critical output rules
+	requiredStrings := []string{
+		"APPROVE",
+		"REQUEST_CHANGES",
+		"MAJOR",
+		"MINOR",
+		"NIT",
+		"verdict",
+		"findings",
+		"CI",
+	}
+
+	for _, s := range requiredStrings {
+		if !strings.Contains(prompt, s) {
+			t.Errorf("prompt should contain %q", s)
+		}
+	}
+}

review/persona_test.go

@@ -0,0 +1,778 @@
+package review
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"gopkg.in/yaml.v3"
+)
+
+func TestLoadBuiltinPersona(t *testing.T) {
+	tests := []struct {
+		name        string
+		personaName string
+		wantErr     bool
+		wantDisplay string
+	}{
+		{
+			name:        "security persona",
+			personaName: "security",
+			wantErr:     false,
+			wantDisplay: "Security Specialist",
+		},
+		{
+			name:        "architect persona",
+			personaName: "architect",
+			wantErr:     false,
+			wantDisplay: "Software Architect",
+		},
+		{
+			name:        "docs persona",
+			personaName: "docs",
+			wantErr:     false,
+			wantDisplay: "Documentation Reviewer",
+		},
+		{
+			name:        "unknown persona",
+			personaName: "nonexistent",
+			wantErr:     true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			p, err := LoadBuiltinPersona(tt.personaName)
+			if tt.wantErr {
+				if err == nil {
+					t.Error("expected error, got nil")
+				}
+				return
+			}
+			if err != nil {
+				t.Fatalf("unexpected error: %v", err)
+			}
+			if p.Name != tt.personaName {
+				t.Errorf("Name = %q, want %q", p.Name, tt.personaName)
+			}
+			if p.DisplayName != tt.wantDisplay {
+				t.Errorf("DisplayName = %q, want %q", p.DisplayName, tt.wantDisplay)
+			}
+			if p.Identity == "" {
+				t.Error("Identity should not be empty")
+			}
+			if len(p.Focus) == 0 {
+				t.Error("Focus should not be empty")
+			}
+		})
+	}
+}
+
+func TestListBuiltinPersonas(t *testing.T) {
+	names := ListBuiltinPersonas()
+	if len(names) == 0 {
+		t.Fatal("expected at least one built-in persona")
+	}
+
+	// Check for expected personas
+	expected := map[string]bool{"security": false, "architect": false, "docs": false}
+	for _, name := range names {
+		if _, ok := expected[name]; ok {
+			expected[name] = true
+		}
+	}
+	for name, found := range expected {
+		if !found {
+			t.Errorf("expected built-in persona %q not found", name)
+		}
+	}
+}
+
+func TestLoadPersonaFromYAMLFile(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "test.yaml")
+
+	content := `# Test persona
+name: test
+display_name: Test Persona
+identity: |
+  You are a test persona.
+  Multi-line identity works.
+focus:
+  - testing
+  - validation
+ignore:
+  - nothing
+severity:
+  major: Big problems
+  minor: Small problems
+  nit: Tiny problems
+`
+
+	if err := os.WriteFile(path, []byte(content), 0644); err != nil {
+		t.Fatalf("failed to write test file: %v", err)
+	}
+
+	p, err := LoadPersona(path)
+	if err != nil {
+		t.Fatalf("LoadPersona failed: %v", err)
+	}
+
+	if p.Name != "test" {
+		t.Errorf("Name = %q, want %q", p.Name, "test")
+	}
+	if p.DisplayName != "Test Persona" {
+		t.Errorf("DisplayName = %q, want %q", p.DisplayName, "Test Persona")
+	}
+	if len(p.Focus) != 2 {
+		t.Errorf("Focus len = %d, want 2", len(p.Focus))
+	}
+	if !strings.Contains(p.Identity, "Multi-line") {
+		t.Error("Identity should contain multi-line content")
+	}
+}
+
+func TestLoadPersonaFromYMLFile(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "test.yml")
+
+	content := `name: test
+display_name: Test YML
+identity: Test identity
+focus:
+  - testing
+ignore: []
+severity:
+  major: Big
+  minor: Small
+  nit: Tiny
+`
+
+	if err := os.WriteFile(path, []byte(content), 0644); err != nil {
+		t.Fatalf("failed to write test file: %v", err)
+	}
+
+	p, err := LoadPersona(path)
+	if err != nil {
+		t.Fatalf("LoadPersona failed: %v", err)
+	}
+
+	if p.Name != "test" {
+		t.Errorf("Name = %q, want %q", p.Name, "test")
+	}
+	if p.DisplayName != "Test YML" {
+		t.Errorf("DisplayName = %q, want %q", p.DisplayName, "Test YML")
+	}
+}
+
+func TestLoadPersonaFromJSONFile(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "test.json")
+
+	content := `{
+		"name": "test",
+		"display_name": "Test Persona",
+		"identity": "You are a test persona.\nMulti-line identity works.",
+		"focus": ["testing", "validation"],
+
+		"ignore": ["nothing"],
+		"severity": {
+			"major": "Big problems",
+			"minor": "Small problems",
+			"nit": "Tiny problems"
+		}
+	}`
+
+	if err := os.WriteFile(path, []byte(content), 0644); err != nil {
+		t.Fatalf("failed to write test file: %v", err)
+	}
+
+	p, err := LoadPersona(path)
+	if err != nil {
+		t.Fatalf("LoadPersona failed: %v", err)
+	}
+
+	if p.Name != "test" {
+		t.Errorf("Name = %q, want %q", p.Name, "test")
+	}
+	if p.DisplayName != "Test Persona" {
+		t.Errorf("DisplayName = %q, want %q", p.DisplayName, "Test Persona")
+	}
+	if len(p.Focus) != 2 {
+		t.Errorf("Focus len = %d, want 2", len(p.Focus))
+	}
+	if !strings.Contains(p.Identity, "Multi-line") {
+		t.Error("Identity should contain multi-line content")
+	}
+}
+
+func TestLoadPersonaValidation(t *testing.T) {
+	tests := []struct {
+		name    string
+		content string
+		ext     string
+		wantErr string
+	}{
+		{
+			name:    "missing name yaml",
+			content: "identity: test\n",
+			ext:     ".yaml",
+			wantErr: "name is required",
+		},
+		{
+			name:    "missing identity yaml",
+			content: "name: test\n",
+			ext:     ".yaml",
+			wantErr: "identity is required",
+		},
+		{
+			name:    "missing name json",
+			content: `{"identity": "test"}`,
+			ext:     ".json",
+			wantErr: "name is required",
+		},
+		{
+			name:    "missing identity json",
+			content: `{"name": "test"}`,
+			ext:     ".json",
+			wantErr: "identity is required",
+		},
+		{
+			name:    "display_name defaults to name",
+			content: "name: test\nidentity: test identity\n",
+			ext:     ".yaml",
+			// No error expected - should succeed
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			dir := t.TempDir()
+			path := filepath.Join(dir, "test"+tt.ext)
+			if err := os.WriteFile(path, []byte(tt.content), 0644); err != nil {
+				t.Fatalf("failed to write test file: %v", err)
+			}
+
+			p, err := LoadPersona(path)
+			if tt.wantErr != "" {
+				if err == nil {
+					t.Errorf("expected error containing %q, got nil", tt.wantErr)
+					return
+				}
+				if !strings.Contains(err.Error(), tt.wantErr) {
+					t.Errorf("error = %q, want containing %q", err.Error(), tt.wantErr)
+				}
+				return
+			}
+			if err != nil {
+				t.Fatalf("unexpected error: %v", err)
+			}
+			// Check display_name defaulting
+			if p.DisplayName == "" {
+				t.Error("DisplayName should default to Name")
+			}
+			if p.DisplayName != p.Name {
+				t.Errorf("DisplayName should default to Name, got %q", p.DisplayName)
+			}
+		})
+	}
+}
+
+func TestLoadPersonaFileNotFound(t *testing.T) {
+	_, err := LoadPersona("/nonexistent/path/persona.yaml")
+	if err == nil {
+		t.Error("expected error for nonexistent file")
+	}
+}
+
+func TestLoadPersonaInvalidYAML(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "invalid.yaml")
+	if err := os.WriteFile(path, []byte("not valid yaml:\n  - [broken"), 0644); err != nil {
+		t.Fatalf("failed to write test file: %v", err)
+	}
+
+	_, err := LoadPersona(path)
+	if err == nil {
+		t.Error("expected error for invalid YAML")
+	}
+}
+
+func TestLoadPersonaInvalidJSON(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "invalid.json")
+	if err := os.WriteFile(path, []byte("not valid json {"), 0644); err != nil {
+		t.Fatalf("failed to write test file: %v", err)
+	}
+
+	_, err := LoadPersona(path)
+	if err == nil {
+		t.Error("expected error for invalid JSON")
+	}
+}
+
+func TestLoadPersonaCaseInsensitiveExtension(t *testing.T) {
+	tests := []struct {
+		name string
+		ext  string
+	}{
+		{"lowercase yaml", ".yaml"},
+		{"uppercase YAML", ".YAML"},
+		{"mixed case Yaml", ".Yaml"},
+		{"lowercase yml", ".yml"},
+		{"uppercase YML", ".YML"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			dir := t.TempDir()
+			path := filepath.Join(dir, "test"+tt.ext)
+			content := "name: test\nidentity: test identity\n"
+			if err := os.WriteFile(path, []byte(content), 0644); err != nil {
+				t.Fatalf("failed to write test file: %v", err)
+			}
+
+			p, err := LoadPersona(path)
+			if err != nil {
+				t.Fatalf("LoadPersona failed for extension %s: %v", tt.ext, err)
+			}
+			if p.Name != "test" {
+				t.Errorf("Name = %q, want %q", p.Name, "test")
+			}
+		})
+	}
+}
+
+func TestCapitalizeFirst(t *testing.T) {
+	tests := []struct {
+		input string
+		want  string
+	}{
+		{"hello", "Hello"},
+		{"Hello", "Hello"},
+		{"HELLO", "HELLO"},
+		{"a", "A"},
+		{"", ""},
+		{"日本語", "日本語"},     // Non-ASCII: Japanese doesn't have case
+		{"über", "Über"},   // German umlaut
+		{"élève", "Élève"}, // French accent
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.input, func(t *testing.T) {
+			got := CapitalizeFirst(tt.input)
+			if got != tt.want {
+				t.Errorf("CapitalizeFirst(%q) = %q, want %q", tt.input, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestListBuiltinPersonasReturnsEmptySlice(t *testing.T) {
+	// ListBuiltinPersonas should return an empty slice (not nil) on error.
+	// We can't easily test the error case, but we can verify the success case
+	// returns a proper slice.
+	names := ListBuiltinPersonas()
+	if names == nil {
+		t.Error("ListBuiltinPersonas should return empty slice, not nil")
+	}
+}
+
+func TestYAMLMultilineStrings(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "multiline.yaml")
+
+	// Test literal block scalar (|) which preserves newlines
+	content := `name: multiline
+display_name: Multiline Test
+identity: |
+  First line.
+  Second line.
+  Third line.
+focus:
+  - item one
+ignore: []
+severity:
+  major: Major issue
+  minor: Minor issue
+  nit: Nit
+`
+
+	if err := os.WriteFile(path, []byte(content), 0644); err != nil {
+		t.Fatalf("failed to write test file: %v", err)
+	}
+
+	p, err := LoadPersona(path)
+	if err != nil {
+		t.Fatalf("LoadPersona failed: %v", err)
+	}
+
+	// Literal block scalar preserves newlines
+	if !strings.Contains(p.Identity, "\n") {
+		t.Error("Identity should contain newlines from literal block scalar")
+	}
+	if !strings.Contains(p.Identity, "Second line") {
+		t.Error("Identity should contain 'Second line'")
+	}
+}
+
+func TestYAMLComments(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "comments.yaml")
+
+	content := `# This is a comment
+name: commented  # inline comment
+display_name: Commented Persona
+# Another comment
+identity: Test identity
+focus:
+  - item  # comment after item
+ignore: []
+severity:
+  major: Major
+  minor: Minor
+  nit: Nit
+`
+
+	if err := os.WriteFile(path, []byte(content), 0644); err != nil {
+		t.Fatalf("failed to write test file: %v", err)
+	}
+
+	p, err := LoadPersona(path)
+	if err != nil {
+		t.Fatalf("LoadPersona failed: %v", err)
+	}
+
+	// Comments should be ignored
+	if p.Name != "commented" {
+		t.Errorf("Name = %q, want %q", p.Name, "commented")
+	}
+	if p.Focus[0] != "item" {
+		t.Errorf("Focus[0] = %q, want %q", p.Focus[0], "item")
+	}
+}
+
+func TestYAMLDeeplyNestedRejection(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "deeply-nested.yaml")
+
+	// Build a deeply nested YAML structure that exceeds MaxYAMLDepth (20).
+	// Each level adds 2 to the depth count (key + value mapping).
+	var sb strings.Builder
+	sb.WriteString("name: test\nidentity: test\nnested:\n")
+	indent := "  "
+	for i := 0; i < 25; i++ {
+		sb.WriteString(strings.Repeat(indent, i+1))
+		sb.WriteString(fmt.Sprintf("level%d:\n", i))
+	}
+	sb.WriteString(strings.Repeat(indent, 26))
+	sb.WriteString("value: too-deep\n")
+
+	if err := os.WriteFile(path, []byte(sb.String()), 0644); err != nil {
+		t.Fatalf("failed to write test file: %v", err)
+	}
+
+	_, err := LoadPersona(path)
+	if err == nil {
+		t.Error("expected error for deeply nested YAML, got nil")
+	}
+	if !strings.Contains(err.Error(), "nesting depth exceeds") {
+		t.Errorf("error = %q, want containing 'nesting depth exceeds'", err.Error())
+	}
+}
+
+func TestYAMLFileSizeLimit(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "huge.yaml")
+
+	// Create a file larger than MaxPersonaFileSize (64 KB)
+	content := "name: test\nidentity: " + strings.Repeat("x", MaxPersonaFileSize+1) + "\n"
+	if err := os.WriteFile(path, []byte(content), 0644); err != nil {
+		t.Fatalf("failed to write test file: %v", err)
+	}
+
+	_, err := LoadPersona(path)
+	if err == nil {
+		t.Error("expected error for oversized file, got nil")
+	}
+	if !strings.Contains(err.Error(), "exceeds maximum size") {
+		t.Errorf("error = %q, want containing 'exceeds maximum size'", err.Error())
+	}
+}
+
+func TestYAMLAliasCycleDetection(t *testing.T) {
+	// Test that our checkYAMLDepth function handles alias cycles gracefully
+	// by using the seen map to prevent infinite recursion.
+	// We test this directly because go-yaml's parser handles most cycles
+	// at parse time, but we need to ensure our checker is robust.
+
+	// Create a node structure where an alias points to a parent node,
+	// simulating what could happen with malicious input that bypasses
+	// go-yaml's cycle detection.
+	parent := &yaml.Node{
+		Kind: yaml.MappingNode,
+		Content: []*yaml.Node{
+			{Kind: yaml.ScalarNode, Value: "name"},
+			{Kind: yaml.ScalarNode, Value: "test"},
+			{Kind: yaml.ScalarNode, Value: "nested"},
+		},
+	}
+
+	// Create a child that aliases back to the parent (artificial cycle)
+	aliasToParent := &yaml.Node{
+		Kind:  yaml.AliasNode,
+		Alias: parent,
+	}
+	parent.Content = append(parent.Content, aliasToParent)
+
+	nodeCount := 0
+	seen := make(map[*yaml.Node]struct{})
+
+	// This should NOT hang or stack overflow - the seen map prevents infinite recursion
+	err := checkYAMLDepth(parent, 0, MaxYAMLDepth, MaxYAMLNodes, seen, &nodeCount)
+	if err != nil {
+		t.Errorf("unexpected error traversing cyclic structure: %v", err)
+	}
+
+	// Verify we tracked the parent in the seen map
+	if _, ok := seen[parent]; !ok {
+		t.Error("parent node not tracked in seen map")
+	}
+}
+
+func TestYAMLMultiDocumentRejection(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "multi.yaml")
+
+	// Multi-document YAML (documents separated by ---)
+	content := `name: first
+identity: first document
+---
+name: second
+identity: second document
+`
+	if err := os.WriteFile(path, []byte(content), 0644); err != nil {
+		t.Fatalf("failed to write test file: %v", err)
+	}
+
+	_, err := LoadPersona(path)
+	if err == nil {
+		t.Error("expected error for multi-document YAML, got nil")
+	}
+	if !strings.Contains(err.Error(), "multi-document") {
+		t.Errorf("error = %q, want containing 'multi-document'", err.Error())
+	}
+}
+
+func TestYAMLNodeCountLimit(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "wide.yaml")
+
+	// Build a YAML structure that's shallow but wide - many keys at the same level
+	// to test the node count limit (should exceed MaxYAMLNodes = 1000)
+	var sb strings.Builder
+	sb.WriteString("name: test\nidentity: test\n")
+	for i := 0; i < 600; i++ {
+		sb.WriteString(fmt.Sprintf("key%d: value%d\n", i, i))
+	}
+
+	if err := os.WriteFile(path, []byte(sb.String()), 0644); err != nil {
+		t.Fatalf("failed to write test file: %v", err)
+	}
+
+	_, err := LoadPersona(path)
+	if err == nil {
+		t.Error("expected error for wide YAML exceeding node count, got nil")
+	}
+	if !strings.Contains(err.Error(), "node count exceeds") {
+		t.Errorf("error = %q, want containing 'node count exceeds'", err.Error())
+	}
+}
+
+func TestCheckYAMLDepthCycleDetectionDirect(t *testing.T) {
+	// Direct test of cycle detection in checkYAMLDepth by creating
+	// a node structure with an artificial cycle.
+	// This tests the seen map logic independent of go-yaml's parsing.
+	node := &yaml.Node{
+		Kind: yaml.MappingNode,
+		Content: []*yaml.Node{
+			{Kind: yaml.ScalarNode, Value: "key"},
+			{Kind: yaml.ScalarNode, Value: "value"},
+		},
+	}
+
+	// Create a cycle by making a child reference the parent
+	cycleChild := &yaml.Node{
+		Kind:  yaml.AliasNode,
+		Alias: node, // Points back to the parent
+	}
+	node.Content = append(node.Content,
+		&yaml.Node{Kind: yaml.ScalarNode, Value: "cyclic"},
+		cycleChild,
+	)
+
+	nodeCount := 0
+	seen := make(map[*yaml.Node]struct{})
+	err := checkYAMLDepth(node, 0, MaxYAMLDepth, MaxYAMLNodes, seen, &nodeCount)
+
+	// Should complete without infinite recursion due to cycle detection
+	if err != nil {
+		t.Errorf("unexpected error: %v", err)
+	}
+	// The seen map should contain multiple entries
+	if len(seen) < 2 {
+		t.Errorf("seen map has %d entries, expected at least 2", len(seen))
+	}
+}
+
+func TestListBuiltinPersonasSortedOrder(t *testing.T) {
+	names := ListBuiltinPersonas()
+	if len(names) < 2 {
+		t.Skip("need at least 2 personas to test ordering")
+	}
+
+	// Verify the list is sorted
+	for i := 1; i < len(names); i++ {
+		if names[i-1] > names[i] {
+			t.Errorf("ListBuiltinPersonas not sorted: %q > %q", names[i-1], names[i])
+		}
+	}
+}
+
+func TestYAMLUnknownFieldsRejected(t *testing.T) {
+	tests := []struct {
+		name    string
+		content string
+		wantErr string
+	}{
+		{
+			name: "unknown top-level field",
+			content: `name: test
+identity: test identity
+unknown_field: should fail
+`,
+			wantErr: "unknown_field",
+		},
+		{
+			name: "typo in field name",
+			content: `name: test
+identiy: typo should fail
+`,
+			wantErr: "identiy",
+		},
+		{
+			name: "unknown field in severity",
+			content: `name: test
+identity: test
+severity:
+  major: Major
+  minro: typo
+`,
+			wantErr: "minro",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			dir := t.TempDir()
+			path := filepath.Join(dir, "unknown.yaml")
+			if err := os.WriteFile(path, []byte(tt.content), 0644); err != nil {
+				t.Fatalf("failed to write test file: %v", err)
+			}
+
+			_, err := LoadPersona(path)
+			if err == nil {
+				t.Errorf("expected error for unknown field %q, got nil", tt.wantErr)
+				return
+			}
+			if !strings.Contains(err.Error(), tt.wantErr) {
+				t.Errorf("error = %q, want containing %q", err.Error(), tt.wantErr)
+			}
+		})
+	}
+}
+
+func TestJSONUnknownFieldsRejected(t *testing.T) {
+	tests := []struct {
+		name    string
+		content string
+		wantErr string
+	}{
+		{
+			name: "unknown top-level field",
+			content: `{
+				"name": "test",
+				"identity": "test identity",
+				"unknown_field": "should fail"
+			}`,
+			wantErr: "unknown_field",
+		},
+		{
+			name: "typo in field name",
+			content: `{
+				"name": "test",
+				"identiy": "typo should fail"
+			}`,
+			wantErr: "identiy",
+		},
+		{
+			name: "unknown field in severity",
+			content: `{
+				"name": "test",
+				"identity": "test",
+				"severity": {
+					"major": "ok",
+					"miner": "typo"
+				}
+			}`,
+			wantErr: "miner",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			dir := t.TempDir()
+			path := filepath.Join(dir, "test.json")
+			if err := os.WriteFile(path, []byte(tt.content), 0644); err != nil {
+				t.Fatalf("failed to write test file: %v", err)
+			}
+
+			_, err := LoadPersona(path)
+			if err == nil {
+				t.Fatal("expected error for unknown field, got nil")
+			}
+			if !strings.Contains(err.Error(), tt.wantErr) {
+				t.Errorf("error = %q, want to contain %q", err.Error(), tt.wantErr)
+			}
+		})
+	}
+}
+
+func TestLoadPersonaSymlink(t *testing.T) {
+	// Create a regular persona file
+	dir := t.TempDir()
+	realFile := filepath.Join(dir, "real.yaml")
+	content := `name: test
+identity: test identity
+`
+	if err := os.WriteFile(realFile, []byte(content), 0644); err != nil {
+		t.Fatalf("failed to write test file: %v", err)
+	}
+
+	// Create a symlink to it
+	symlink := filepath.Join(dir, "link.yaml")
+	if err := os.Symlink(realFile, symlink); err != nil {
+		t.Fatalf("failed to create symlink: %v", err)
+	}
+
+	// LoadPersona should work via symlink
+	p, err := LoadPersona(symlink)
+	if err != nil {
+		t.Fatalf("LoadPersona via symlink failed: %v", err)
+	}
+	if p.Name != "test" {
+		t.Errorf("Name = %q, want %q", p.Name, "test")
+	}
+}

review/personas/architect.yaml

@@ -0,0 +1,37 @@
+# Software Architect Persona
+# Focuses on design quality, patterns, and code organization
+
+name: architect
+display_name: Software Architect
+
+identity: |
+  You are a software architect reviewing code for design quality.
+
+  Your expertise:
+  - Design patterns and anti-patterns
+  - Code organization and module boundaries
+  - API design and contracts
+  - Testability and dependency injection
+  - Consistency with existing architecture
+  - Technical debt identification
+
+focus:
+  - Design pattern violations or misuse
+  - Module boundary violations (inappropriate coupling)
+  - API design issues (unclear contracts, leaky abstractions)
+  - Testability problems (hidden dependencies, god objects)
+  - Inconsistency with existing codebase patterns
+  - Unnecessary complexity or over-engineering
+  - Missing abstractions or premature abstraction
+
+ignore:
+  - Security vulnerabilities (security persona handles these)
+  - Performance micro-optimizations
+  - Code style and formatting
+  - Documentation typos
+  - Test implementation details
+
+severity:
+  major: "Architectural violations that will cause maintenance problems or make the codebase harder to evolve"
+  minor: "Design issues that reduce clarity or testability but don't block progress"
+  nit: "Minor pattern deviations or style preferences"

review/personas/docs.yaml

@@ -0,0 +1,36 @@
+# Documentation Reviewer Persona
+# Focuses on clarity, documentation quality, and self-documenting code
+
+name: docs
+display_name: Documentation Reviewer
+
+identity: |
+  You are a documentation specialist reviewing code for clarity and documentation quality.
+
+  Your expertise:
+  - API documentation and examples
+  - Code comments and their accuracy
+  - Error message clarity
+  - README and guide quality
+  - Naming clarity and self-documenting code
+
+focus:
+  - Missing or outdated documentation
+  - Unclear or misleading comments
+  - Poor error messages (cryptic, unhelpful, missing context)
+  - Confusing naming (functions, variables, types)
+  - Missing examples for complex APIs
+  - Inconsistent terminology
+  - Documentation that contradicts the code
+
+ignore:
+  - Security vulnerabilities
+  - Performance issues
+  - Design patterns
+  - Test coverage
+  - Code style (unless it affects readability)
+
+severity:
+  major: "Documentation that actively misleads or missing docs for critical functionality"
+  minor: "Unclear documentation or poor error messages that will confuse users"
+  nit: "Minor clarity improvements or typo fixes"

review/personas/security.yaml

@@ -0,0 +1,37 @@
+# Security Specialist Persona
+# Focuses on vulnerabilities, auth issues, and security best practices
+
+name: security
+display_name: Security Specialist
+
+identity: |
+  You are a security specialist reviewing code for vulnerabilities.
+
+  Your expertise:
+  - OWASP Top 10 vulnerabilities
+  - Injection attacks (SQL, command, path traversal, template)
+  - Authentication and authorization patterns
+  - Secrets management and exposure risks
+  - Race conditions with security implications
+  - Event sourcing attack vectors (replay attacks, event injection)
+
+focus:
+  - Injection attacks (SQL, command, path traversal, template injection)
+  - Authentication and authorization gaps or bypasses
+  - Secrets exposure (hardcoded credentials, tokens in logs, config leaks)
+  - Input validation failures (unsanitized input, unsafe deserialization)
+  - Race conditions that could be exploited
+  - Cryptographic weaknesses (weak algorithms, improper key handling)
+  - Information disclosure through error messages or logs
+
+ignore:
+  - Code style and naming conventions
+  - Performance optimizations (unless security-related)
+  - Documentation quality
+  - General code quality or readability
+  - Test coverage
+
+severity:
+  major: "Exploitable vulnerabilities: auth bypass, injection, data exfiltration, privilege escalation, RCE"
+  minor: "Defense-in-depth issues: missing rate limiting, verbose errors, weak input validation"
+  nit: "Theoretical risks with low exploitability or impact"

review/prompt.go

@@ -1,3 +1,5 @@
+// Package review builds prompts for AI code review and parses LLM responses
+// into structured review results.
 package review
 
 import (
@@ -5,8 +7,32 @@ import (
 	"strings"
 )
 
-// BuildSystemPrompt constructs the system prompt for the LLM reviewer.
-func BuildSystemPrompt(conventions, patterns string) string {
+// outputSchemaJSON is the shared JSON output format specification used by both
+// the generic reviewer and persona-based reviewers.
+const outputSchemaJSON = `{
+  "verdict": "APPROVE" or "REQUEST_CHANGES",
+  "summary": "Brief overall assessment (1-3 sentences)",
+  "findings": [
+    {
+      "severity": "MAJOR" or "MINOR" or "NIT",
+      "file": "path/to/file",
+      "line": <line number from the diff>,
+      "finding": "Description of the issue"
+    }
+  ],
+  "recommendation": "Full recommendation text explaining your verdict"
+}`
+
+// verdictRules is the shared verdict determination rules.
+const verdictRules = `Rules:
+- If there are any MAJOR findings → verdict must be REQUEST_CHANGES
+- If there are no MAJOR findings → verdict should be APPROVE
+- If CI has failed → verdict must be REQUEST_CHANGES with a finding noting the CI failure`
+
+// BuildSystemBase returns the core system prompt instructions without
+// patterns or conventions. Used by the budget package to separate
+// trimmable from non-trimmable content.
+func BuildSystemBase() string {
 	var sb strings.Builder
 
 	sb.WriteString("You are an expert code reviewer. Review the provided pull request diff carefully.\n\n")
@@ -19,27 +45,22 @@ func BuildSystemPrompt(conventions, patterns string) string {
 	sb.WriteString("2. Consider the CI status — if CI has failed, that is an automatic REQUEST_CHANGES regardless of code quality.\n")
 	sb.WriteString("3. Output your review as structured JSON (and ONLY JSON, no markdown fences or other text).\n\n")
 	sb.WriteString("Output format:\n")
-	sb.WriteString("{\n")
-	sb.WriteString("  \"verdict\": \"APPROVE\" or \"REQUEST_CHANGES\",\n")
-	sb.WriteString("  \"summary\": \"Brief overall assessment (1-3 sentences)\",\n")
-	sb.WriteString("  \"findings\": [\n")
-	sb.WriteString("    {\n")
-	sb.WriteString("      \"severity\": \"MAJOR\" or \"MINOR\" or \"NIT\",\n")
-	sb.WriteString("      \"file\": \"path/to/file\",\n")
-	sb.WriteString("      \"line\": <line number from the diff>,\n")
-	sb.WriteString("      \"finding\": \"Description of the issue\"\n")
-	sb.WriteString("    }\n")
-	sb.WriteString("  ],\n")
-	sb.WriteString("  \"recommendation\": \"Full recommendation text explaining your verdict\"\n")
-	sb.WriteString("}\n\n")
-	sb.WriteString("Rules:\n")
-	sb.WriteString("- If there are any MAJOR findings → verdict must be REQUEST_CHANGES\n")
-	sb.WriteString("- If there are no MAJOR findings → verdict should be APPROVE\n")
-	sb.WriteString("- If CI has failed → verdict must be REQUEST_CHANGES with a finding noting the CI failure\n")
-	sb.WriteString("- Be thorough but fair. Don't nitpick style unless it impacts readability significantly.\n")
+	sb.WriteString(outputSchemaJSON)
+	sb.WriteString("\n\n")
+	sb.WriteString(verdictRules)
+	sb.WriteString("\n- Be thorough but fair. Don't nitpick style unless it impacts readability significantly.\n")
 	sb.WriteString("- Line numbers should reference the new file line numbers from the diff headers.\n")
 	sb.WriteString("- If the diff is empty or trivial (only formatting/whitespace), APPROVE with no findings.\n")
 
+	return sb.String()
+}
+
+// BuildSystemPrompt constructs the full system prompt with patterns and conventions.
+// Deprecated: Use BuildSystemBase with budget.Fit for context-aware assembly.
+func BuildSystemPrompt(conventions, patterns string) string {
+	var sb strings.Builder
+	sb.WriteString(BuildSystemBase())
+
 	if patterns != "" {
 		sb.WriteString(fmt.Sprintf("\n\n## Language Patterns & Idioms\n\nUse the following patterns as review criteria. Code that violates these established patterns is a finding:\n\n%s\n", patterns))
 	}
@@ -51,8 +72,9 @@ func BuildSystemPrompt(conventions, patterns string) string {
 	return sb.String()
 }
 
-// BuildUserPrompt constructs the user message with PR context.
-func BuildUserPrompt(title, description, diff, fileContext string, ciPassed bool, ciDetails string) string {
+// BuildUserMeta returns the PR metadata header (title, description, CI status)
+// without the diff or file context. Used by the budget package.
+func BuildUserMeta(title, description string, ciPassed bool, ciDetails string) string {
 	var sb strings.Builder
 
 	sb.WriteString(fmt.Sprintf("## Pull Request: %s\n\n", title))
@@ -71,6 +93,16 @@ func BuildUserPrompt(title, description, diff, fileContext string, ciPassed bool
 		sb.WriteString(fmt.Sprintf("CI Details: %s\n", ciDetails))
 	}
 
+	return sb.String()
+}
+
+// BuildUserPrompt constructs the user message with PR context.
+// Deprecated: Use BuildUserMeta with budget.Fit for context-aware assembly.
+func BuildUserPrompt(title, description, diff, fileContext string, ciPassed bool, ciDetails string) string {
+	var sb strings.Builder
+
+	sb.WriteString(BuildUserMeta(title, description, ciPassed, ciDetails))
+
 	if fileContext != "" {
 		sb.WriteString("\n### Full File Context (modified files)\n\n")
 		sb.WriteString(fileContext)

review/prompt_test.go

@@ -116,3 +116,43 @@ func TestBuildUserPrompt_WithoutFileContext(t *testing.T) {
 		t.Error("should not include file context section when empty")
 	}
 }
+
+
+func TestBuildSystemBase(t *testing.T) {
+	result := BuildSystemBase()
+	if result == "" {
+		t.Fatal("BuildSystemBase returned empty string")
+	}
+	if !strings.Contains(result, "expert code reviewer") {
+		t.Error("expected reviewer role in system base")
+	}
+	if !strings.Contains(result, "REQUEST_CHANGES") {
+		t.Error("expected verdict format in system base")
+	}
+	if !strings.Contains(result, "JSON") {
+		t.Error("expected JSON output instruction in system base")
+	}
+}
+
+func TestBuildUserMeta(t *testing.T) {
+	result := BuildUserMeta("Fix bug", "Some description", true, "all checks passed")
+	if !strings.Contains(result, "Fix bug") {
+		t.Error("expected title in user meta")
+	}
+	if !strings.Contains(result, "Some description") {
+		t.Error("expected description in user meta")
+	}
+	if !strings.Contains(result, "PASSED") {
+		t.Error("expected CI PASSED status")
+	}
+}
+
+func TestBuildUserMeta_CIFailed(t *testing.T) {
+	result := BuildUserMeta("Title", "", false, "test job failed")
+	if !strings.Contains(result, "FAILED") {
+		t.Error("expected CI FAILED status")
+	}
+	if strings.Contains(result, "Description") {
+		t.Error("expected no description section when empty")
+	}
+}

review/repo_persona.go

@@ -0,0 +1,137 @@
+package review
+
+import (
+	"context"
+	"log/slog"
+	"strings"
+
+	"gitea.weiker.me/rodin/review-bot/vcs"
+)
+
+// RepoPersonaPath is the directory path where repo-specific personas are stored.
+const RepoPersonaPath = ".review-bot/personas"
+
+// LoadRepoPersonas fetches personas from a repository's .review-bot/personas/ directory.
+// Returns an empty map (not nil) if the directory doesn't exist or is empty.
+// Individual parse failures are logged and skipped; the remaining personas are still returned.
+// Auth errors and other non-404 errors are propagated.
+// Files exceeding MaxPersonaFileSize are rejected to prevent resource exhaustion.
+func LoadRepoPersonas(ctx context.Context, client vcs.FileReader, owner, repo string) (map[string]*Persona, error) {
+	result := make(map[string]*Persona)
+
+	entries, err := client.ListContents(ctx, owner, repo, RepoPersonaPath)
+	if err != nil {
+		// Check if this is a 404 (directory doesn't exist) - expected case
+		if isNotFoundError(err) {
+			slog.Debug("no repo personas directory found", "repo", owner+"/"+repo)
+			return result, nil
+		}
+		// Other errors (auth, server) should propagate
+		return nil, err
+	}
+
+	if len(entries) == 0 {
+		slog.Debug("repo personas directory is empty", "repo", owner+"/"+repo)
+		return result, nil
+	}
+
+	for _, entry := range entries {
+		if entry.Type != "file" {
+			continue
+		}
+		// Only process YAML files
+		if !isYAMLFile(entry.Name) {
+			continue
+		}
+
+		content, err := client.GetFileContent(ctx, owner, repo, entry.Path, "")
+		if err != nil {
+			slog.Warn("could not fetch repo persona file",
+				"file", entry.Path,
+				"repo", owner+"/"+repo,
+				"error", err)
+			continue
+		}
+
+		// Enforce size limit before parsing to prevent resource exhaustion
+		if len(content) > MaxPersonaFileSize {
+			slog.Warn("repo persona file exceeds maximum size",
+				"file", entry.Path,
+				"repo", owner+"/"+repo,
+				"size", len(content),
+				"max", MaxPersonaFileSize)
+			continue
+		}
+
+		persona, err := ParsePersonaBytes([]byte(content), entry.Path)
+		if err != nil {
+			slog.Warn("could not parse repo persona file",
+				"file", entry.Path,
+				"repo", owner+"/"+repo,
+				"error", err)
+			continue
+		}
+
+		result[persona.Name] = persona
+		slog.Debug("loaded repo persona",
+			"name", persona.Name,
+			"file", entry.Path,
+			"repo", owner+"/"+repo)
+	}
+
+	return result, nil
+}
+
+// MergePersonas combines built-in personas with repo personas.
+// Repo personas take precedence on name collision.
+// Returns a new map; inputs are not modified.
+func MergePersonas(builtin, repo map[string]*Persona) map[string]*Persona {
+	result := make(map[string]*Persona, len(builtin)+len(repo))
+
+	// Copy built-in personas first
+	for name, p := range builtin {
+		result[name] = p
+	}
+
+	// Overlay repo personas (override on collision)
+	for name, p := range repo {
+		if _, exists := result[name]; exists {
+			slog.Debug("repo persona overrides built-in", "name", name)
+		}
+		result[name] = p
+	}
+
+	return result
+}
+
+// GetBuiltinPersonasMap returns all built-in personas as a map keyed by name.
+// Returns an empty map (not nil) if loading fails.
+func GetBuiltinPersonasMap() map[string]*Persona {
+	result := make(map[string]*Persona)
+	for _, name := range ListBuiltinPersonas() {
+		p, err := LoadBuiltinPersona(name)
+		if err != nil {
+			slog.Warn("could not load built-in persona", "name", name, "error", err)
+			continue
+		}
+		result[name] = p
+	}
+	return result
+}
+
+// isYAMLFile checks if a filename has a YAML extension.
+func isYAMLFile(name string) bool {
+	lower := strings.ToLower(name)
+	return strings.HasSuffix(lower, ".yaml") || strings.HasSuffix(lower, ".yml")
+}
+
+// isNotFoundError checks if an error represents a 404 response.
+// This uses a specific "HTTP 404" substring match rather than a generic "not found"
+// match to avoid masking authentication failures or transport errors that might
+// contain "not found" in their message.
+func isNotFoundError(err error) bool {
+	if err == nil {
+		return false
+	}
+	return strings.Contains(err.Error(), "HTTP 404")
+}

review/repo_persona_test.go

@@ -0,0 +1,412 @@
+package review
+
+import (
+	"context"
+	"errors"
+	"strings"
+	"testing"
+
+	"gitea.weiker.me/rodin/review-bot/vcs"
+)
+
+func TestParsePersonaBytes(t *testing.T) {
+	tests := []struct {
+		name     string
+		data     string
+		source   string
+		wantName string
+		wantErr  string
+	}{
+		{
+			name: "valid yaml",
+			data: "name: test\nidentity: test identity\nfocus:\n  - testing\n",
+			source:   "test.yaml",
+			wantName: "test",
+		},
+		{
+			name:    "missing name",
+			data:    "identity: test\n",
+			source:  "test.yaml",
+			wantErr: "name is required",
+		},
+		{
+			name:    "invalid yaml",
+			data:    "not: valid:\n  yaml: [broken",
+			source:  "test.yaml",
+			wantErr: "parse",
+		},
+		{
+			name:     "json format by extension",
+			data:     `{"name": "jsontest", "identity": "json identity"}`,
+			source:   "test.json",
+			wantName: "jsontest",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			p, err := ParsePersonaBytes([]byte(tt.data), tt.source)
+			if tt.wantErr != "" {
+				if err == nil {
+					t.Fatalf("expected error containing %q, got nil", tt.wantErr)
+				}
+				if !strings.Contains(err.Error(), tt.wantErr) {
+					t.Errorf("error = %q, want containing %q", err.Error(), tt.wantErr)
+				}
+				return
+			}
+			if err != nil {
+				t.Fatalf("unexpected error: %v", err)
+			}
+			if p.Name != tt.wantName {
+				t.Errorf("Name = %q, want %q", p.Name, tt.wantName)
+			}
+		})
+	}
+}
+
+// mockGiteaClient implements vcs.FileReader for testing.
+type mockGiteaClient struct {
+	contents map[string][]vcs.ContentEntry // path -> entries
+	files    map[string]string             // path -> content
+	listErr  error
+	fileErr  map[string]error // path -> error
+}
+
+func (m *mockGiteaClient) ListContents(ctx context.Context, owner, repo, path string) ([]vcs.ContentEntry, error) {
+	if m.listErr != nil {
+		return nil, m.listErr
+	}
+	entries, ok := m.contents[path]
+	if !ok {
+		return nil, errors.New("list contents .review-bot/personas: HTTP 404: not found")
+	}
+	return entries, nil
+}
+
+func (m *mockGiteaClient) GetFileContent(ctx context.Context, owner, repo, filepath, ref string) (string, error) {
+	if m.fileErr != nil {
+		if err, ok := m.fileErr[filepath]; ok {
+			return "", err
+		}
+	}
+	content, ok := m.files[filepath]
+	if !ok {
+		return "", errors.New("HTTP 404: file not found")
+	}
+	return content, nil
+}
+
+func TestLoadRepoPersonas(t *testing.T) {
+	ctx := context.Background()
+
+	t.Run("directory not found returns empty map", func(t *testing.T) {
+		client := &mockGiteaClient{} // No contents configured -> 404
+		personas, err := LoadRepoPersonas(ctx, client, "owner", "repo")
+		if err != nil {
+			t.Fatalf("unexpected error: %v", err)
+		}
+		if personas == nil {
+			t.Error("expected empty map, got nil")
+		}
+		if len(personas) != 0 {
+			t.Errorf("expected 0 personas, got %d", len(personas))
+		}
+	})
+
+	t.Run("empty directory returns empty map", func(t *testing.T) {
+		client := &mockGiteaClient{
+			contents: map[string][]vcs.ContentEntry{
+				RepoPersonaPath: {},
+			},
+		}
+		personas, err := LoadRepoPersonas(ctx, client, "owner", "repo")
+		if err != nil {
+			t.Fatalf("unexpected error: %v", err)
+		}
+		if len(personas) != 0 {
+			t.Errorf("expected 0 personas, got %d", len(personas))
+		}
+	})
+
+	t.Run("loads valid personas", func(t *testing.T) {
+		client := &mockGiteaClient{
+			contents: map[string][]vcs.ContentEntry{
+				RepoPersonaPath: {
+					{Name: "trading.yaml", Path: ".review-bot/personas/trading.yaml", Type: "file"},
+					{Name: "crypto.yaml", Path: ".review-bot/personas/crypto.yaml", Type: "file"},
+				},
+			},
+			files: map[string]string{
+				".review-bot/personas/trading.yaml": "name: trading\ndisplay_name: Trading Expert\nidentity: You are a trading expert.\nfocus:\n  - order handling\n  - risk management\n",
+				".review-bot/personas/crypto.yaml":  "name: crypto\ndisplay_name: Crypto Expert\nidentity: You are a cryptography expert.\nfocus:\n  - key management\n  - encryption\n",
+			},
+		}
+		personas, err := LoadRepoPersonas(ctx, client, "owner", "repo")
+		if err != nil {
+			t.Fatalf("unexpected error: %v", err)
+		}
+		if len(personas) != 2 {
+			t.Fatalf("expected 2 personas, got %d", len(personas))
+		}
+		if personas["trading"] == nil {
+			t.Error("expected trading persona")
+		}
+		if personas["crypto"] == nil {
+			t.Error("expected crypto persona")
+		}
+		if personas["trading"].DisplayName != "Trading Expert" {
+			t.Errorf("trading display name = %q, want %q", personas["trading"].DisplayName, "Trading Expert")
+		}
+	})
+
+	t.Run("skips invalid persona files", func(t *testing.T) {
+		client := &mockGiteaClient{
+			contents: map[string][]vcs.ContentEntry{
+				RepoPersonaPath: {
+					{Name: "valid.yaml", Path: ".review-bot/personas/valid.yaml", Type: "file"},
+					{Name: "invalid.yaml", Path: ".review-bot/personas/invalid.yaml", Type: "file"},
+				},
+			},
+			files: map[string]string{
+				".review-bot/personas/valid.yaml":   "name: valid\nidentity: Valid persona\n",
+				".review-bot/personas/invalid.yaml": "not valid yaml: [broken",
+			},
+		}
+		personas, err := LoadRepoPersonas(ctx, client, "owner", "repo")
+		if err != nil {
+			t.Fatalf("unexpected error: %v", err)
+		}
+		if len(personas) != 1 {
+			t.Fatalf("expected 1 persona (skipped invalid), got %d", len(personas))
+		}
+		if personas["valid"] == nil {
+			t.Error("expected valid persona")
+		}
+	})
+
+	t.Run("skips non-yaml files", func(t *testing.T) {
+		client := &mockGiteaClient{
+			contents: map[string][]vcs.ContentEntry{
+				RepoPersonaPath: {
+					{Name: "persona.yaml", Path: ".review-bot/personas/persona.yaml", Type: "file"},
+					{Name: "README.md", Path: ".review-bot/personas/README.md", Type: "file"},
+					{Name: "notes.txt", Path: ".review-bot/personas/notes.txt", Type: "file"},
+				},
+			},
+			files: map[string]string{
+				".review-bot/personas/persona.yaml": "name: test\nidentity: Test persona\n",
+				".review-bot/personas/README.md":    "# Personas\n\nPut your personas here.",
+			},
+		}
+		personas, err := LoadRepoPersonas(ctx, client, "owner", "repo")
+		if err != nil {
+			t.Fatalf("unexpected error: %v", err)
+		}
+		if len(personas) != 1 {
+			t.Fatalf("expected 1 persona (yaml only), got %d", len(personas))
+		}
+	})
+
+	t.Run("skips subdirectories", func(t *testing.T) {
+		client := &mockGiteaClient{
+			contents: map[string][]vcs.ContentEntry{
+				RepoPersonaPath: {
+					{Name: "persona.yaml", Path: ".review-bot/personas/persona.yaml", Type: "file"},
+					{Name: "subdir", Path: ".review-bot/personas/subdir", Type: "dir"},
+				},
+			},
+			files: map[string]string{
+				".review-bot/personas/persona.yaml": "name: test\nidentity: Test persona\n",
+			},
+		}
+		personas, err := LoadRepoPersonas(ctx, client, "owner", "repo")
+		if err != nil {
+			t.Fatalf("unexpected error: %v", err)
+		}
+		if len(personas) != 1 {
+			t.Fatalf("expected 1 persona (files only), got %d", len(personas))
+		}
+	})
+
+	t.Run("propagates auth errors", func(t *testing.T) {
+		client := &mockGiteaClient{
+			listErr: errors.New("HTTP 401: unauthorized"),
+		}
+		_, err := LoadRepoPersonas(ctx, client, "owner", "repo")
+		if err == nil {
+			t.Fatal("expected error for auth failure")
+		}
+		if !strings.Contains(err.Error(), "401") {
+			t.Errorf("error = %q, want containing '401'", err.Error())
+		}
+	})
+
+	t.Run("skips files that fail to fetch", func(t *testing.T) {
+		client := &mockGiteaClient{
+			contents: map[string][]vcs.ContentEntry{
+				RepoPersonaPath: {
+					{Name: "good.yaml", Path: ".review-bot/personas/good.yaml", Type: "file"},
+					{Name: "bad.yaml", Path: ".review-bot/personas/bad.yaml", Type: "file"},
+				},
+			},
+			files: map[string]string{
+				".review-bot/personas/good.yaml": "name: good\nidentity: Good persona\n",
+			},
+			fileErr: map[string]error{
+				".review-bot/personas/bad.yaml": errors.New("HTTP 500: internal server error"),
+			},
+		}
+		personas, err := LoadRepoPersonas(ctx, client, "owner", "repo")
+		if err != nil {
+			t.Fatalf("unexpected error: %v", err)
+		}
+		if len(personas) != 1 {
+			t.Fatalf("expected 1 persona (skipped failed fetch), got %d", len(personas))
+		}
+	})
+
+	t.Run("skips oversized files", func(t *testing.T) {
+		oversizedContent := strings.Repeat("a", MaxPersonaFileSize+1)
+		client := &mockGiteaClient{
+			contents: map[string][]vcs.ContentEntry{
+				RepoPersonaPath: {
+					{Name: "normal.yaml", Path: ".review-bot/personas/normal.yaml", Type: "file"},
+					{Name: "huge.yaml", Path: ".review-bot/personas/huge.yaml", Type: "file"},
+				},
+			},
+			files: map[string]string{
+				".review-bot/personas/normal.yaml": "name: normal\nidentity: Normal sized persona\n",
+				".review-bot/personas/huge.yaml":   oversizedContent,
+			},
+		}
+		personas, err := LoadRepoPersonas(ctx, client, "owner", "repo")
+		if err != nil {
+			t.Fatalf("unexpected error: %v", err)
+		}
+		if len(personas) != 1 {
+			t.Fatalf("expected 1 persona (skipped oversized), got %d", len(personas))
+		}
+		if personas["normal"] == nil {
+			t.Error("expected normal persona")
+		}
+	})
+}
+
+func TestMergePersonas(t *testing.T) {
+	builtin := map[string]*Persona{
+		"security": {Name: "security", Identity: "Built-in security"},
+		"docs":     {Name: "docs", Identity: "Built-in docs"},
+	}
+	repo := map[string]*Persona{
+		"security": {Name: "security", Identity: "Repo security override"},
+		"trading":  {Name: "trading", Identity: "Repo trading"},
+	}
+
+	merged := MergePersonas(builtin, repo)
+
+	t.Run("repo overrides builtin on collision", func(t *testing.T) {
+		if merged["security"].Identity != "Repo security override" {
+			t.Errorf("security identity = %q, want repo override", merged["security"].Identity)
+		}
+	})
+
+	t.Run("builtin preserved when no collision", func(t *testing.T) {
+		if merged["docs"].Identity != "Built-in docs" {
+			t.Errorf("docs identity = %q, want built-in", merged["docs"].Identity)
+		}
+	})
+
+	t.Run("repo-only persona added", func(t *testing.T) {
+		if merged["trading"] == nil {
+			t.Error("expected trading persona from repo")
+		}
+		if merged["trading"].Identity != "Repo trading" {
+			t.Errorf("trading identity = %q, want repo", merged["trading"].Identity)
+		}
+	})
+
+	t.Run("original maps not modified", func(t *testing.T) {
+		if builtin["trading"] != nil {
+			t.Error("builtin map was modified")
+		}
+		if len(repo) != 2 {
+			t.Error("repo map was modified")
+		}
+	})
+}
+
+func TestGetBuiltinPersonasMap(t *testing.T) {
+	personas := GetBuiltinPersonasMap()
+
+	if len(personas) == 0 {
+		t.Fatal("expected at least one built-in persona")
+	}
+
+	expected := []string{"security", "architect", "docs"}
+	for _, name := range expected {
+		if personas[name] == nil {
+			t.Errorf("expected built-in persona %q", name)
+		}
+	}
+
+	for name, p := range personas {
+		if p.Name != name {
+			t.Errorf("persona %q has mismatched name %q", name, p.Name)
+		}
+		if p.Identity == "" {
+			t.Errorf("persona %q has empty identity", name)
+		}
+	}
+}
+
+func TestIsYAMLFile(t *testing.T) {
+	tests := []struct {
+		name string
+		want bool
+	}{
+		{"test.yaml", true},
+		{"test.yml", true},
+		{"test.YAML", true},
+		{"test.YML", true},
+		{"test.json", false},
+		{"test.md", false},
+		{"test.txt", false},
+		{"yaml", false},
+		{"yaml.md", false},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := isYAMLFile(tt.name); got != tt.want {
+				t.Errorf("isYAMLFile(%q) = %v, want %v", tt.name, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestIsNotFoundError(t *testing.T) {
+	tests := []struct {
+		err  error
+		want bool
+	}{
+		{nil, false},
+		{errors.New("HTTP 404: not found"), true},
+		{errors.New("HTTP 404"), true},
+		{errors.New("something not found"), false},
+		{errors.New("HTTP 401: unauthorized"), false},
+		{errors.New("connection refused"), false},
+	}
+
+	for _, tt := range tests {
+		name := "nil"
+		if tt.err != nil {
+			name = tt.err.Error()
+		}
+		t.Run(name, func(t *testing.T) {
+			if got := isNotFoundError(tt.err); got != tt.want {
+				t.Errorf("isNotFoundError(%v) = %v, want %v", tt.err, got, tt.want)
+			}
+		})
+	}
+}

scripts/check-deps.sh

@@ -0,0 +1,127 @@
+#!/usr/bin/env bash
+# check-deps.sh - Enforces the strict dependency allowlist from CONVENTIONS.md
+# Exit 1 if any unapproved import is found.
+#
+# Requires: Bash 4+ (for associative arrays), Go toolchain
+# 
+# The allowlist is parsed from CONVENTIONS.md to maintain a single source of truth.
+# Enforces Scope column: "test only" packages cannot appear in non-test code.
+
+set -euo pipefail
+
+# Check bash version
+if ((BASH_VERSINFO[0] < 4)); then
+    echo "❌ Bash 4+ required (found ${BASH_VERSION})"
+    echo "   On macOS: brew install bash"
+    exit 1
+fi
+
+CONVENTIONS_FILE="${1:-CONVENTIONS.md}"
+
+if [ ! -f "$CONVENTIONS_FILE" ]; then
+    echo "❌ CONVENTIONS.md not found"
+    exit 1
+fi
+
+# Parse approved packages from CONVENTIONS.md table using awk (POSIX-compatible)
+# Format: | `package` | use case | scope |
+declare -A ALLOWED_PROD=()
+declare -A ALLOWED_TEST=()
+
+while IFS= read -r line; do
+    # Use awk to extract package and scope from table row
+    pkg=$(echo "$line" | awk -F'|' '{gsub(/^[[:space:]]*`|`[[:space:]]*$/, "", $2); print $2}')
+    scope=$(echo "$line" | awk -F'|' '{gsub(/^[[:space:]]+|[[:space:]]+$/, "", $4); print tolower($4)}')
+    
+    if [ -n "$pkg" ] && [ "$pkg" != "Package" ] && [[ "$pkg" =~ ^[a-zA-Z] ]]; then
+        if [[ "$scope" == *"test"* ]]; then
+            ALLOWED_TEST["$pkg"]=1
+        else
+            ALLOWED_PROD["$pkg"]=1
+        fi
+    fi
+done < <(grep '| `' "$CONVENTIONS_FILE" 2>/dev/null || true)
+
+ALL_ALLOWED=("${!ALLOWED_PROD[@]}" "${!ALLOWED_TEST[@]}")
+
+if [ ${#ALL_ALLOWED[@]} -eq 0 ]; then
+    echo "⚠️  No approved packages found in $CONVENTIONS_FILE"
+    echo "   (This is fine if you want stdlib-only)"
+fi
+
+# Helper: check if import matches any package in an associative array (literal prefix, no glob)
+matches_allowlist() {
+    local import="$1"
+    shift
+    local -n allowlist=$1
+    
+    for allowed in "${!allowlist[@]}"; do
+        # Exact match
+        if [ "$import" = "$allowed" ]; then
+            return 0
+        fi
+        # Literal prefix match for subpackages: must match "pkg/" exactly
+        if [ "${import#"$allowed/"}" != "$import" ]; then
+            return 0
+        fi
+    done
+    return 1
+}
+
+# Get direct module dependencies from go.mod
+DIRECT_IMPORTS=$(go list -m -f '{{if and (not .Indirect) (not .Main)}}{{.Path}}{{end}}' all 2>&1) || {
+    echo "❌ Failed to list dependencies: $DIRECT_IMPORTS"
+    exit 1
+}
+DIRECT_IMPORTS=$(echo "$DIRECT_IMPORTS" | grep -v '^$' || true)
+
+if [ -z "$DIRECT_IMPORTS" ]; then
+    echo "✅ No external dependencies"
+    exit 0
+fi
+
+# Check ALL direct dependencies are in some allowlist
+VIOLATIONS=""
+while IFS= read -r import; do
+    [ -z "$import" ] && continue
+    
+    if ! matches_allowlist "$import" ALLOWED_PROD && ! matches_allowlist "$import" ALLOWED_TEST; then
+        VIOLATIONS="${VIOLATIONS}  - ${import} (not in allowlist)"$'\n'
+    fi
+done <<< "$DIRECT_IMPORTS"
+
+if [ -n "$VIOLATIONS" ]; then
+    echo "❌ UNAPPROVED DEPENDENCIES DETECTED"
+    echo ""
+    echo "The following imports are not in the allowlist:"
+    printf "%s" "$VIOLATIONS"
+    echo ""
+    echo "To add a dependency, update CONVENTIONS.md (requires Aaron's approval)"
+    exit 1
+fi
+
+# Enforce Scope: test-only packages must not appear in non-test code
+# Get imports used by non-test code only (go list -deps without -test excludes test deps)
+PROD_IMPORTS=$(go list -deps -f '{{if not .Standard}}{{.ImportPath}}{{end}}' ./... 2>/dev/null || true)
+
+TEST_ONLY_IN_PROD=""
+for test_pkg in "${!ALLOWED_TEST[@]}"; do
+    # Use word-boundary matching: exact match or followed by /
+    if echo "$PROD_IMPORTS" | grep -qE "^${test_pkg}(/|\$|$)"; then
+        TEST_ONLY_IN_PROD="${TEST_ONLY_IN_PROD}  - ${test_pkg} (marked 'test only' but used in production code)"$'\n'
+    fi
+done
+
+if [ -n "$TEST_ONLY_IN_PROD" ]; then
+    echo "❌ TEST-ONLY DEPENDENCIES IN PRODUCTION CODE"
+    echo ""
+    printf "%s" "$TEST_ONLY_IN_PROD"
+    echo ""
+    echo "These packages are marked 'test only' in CONVENTIONS.md"
+    echo "and must only be imported from *_test.go files."
+    exit 1
+fi
+
+echo "✅ All dependencies are approved"
+echo "   Direct module deps: $(echo "$DIRECT_IMPORTS" | wc -l | tr -d ' ')"
+echo "   Production allowlist: ${#ALLOWED_PROD[@]}, Test-only allowlist: ${#ALLOWED_TEST[@]}"

vcs/check_test.go

@@ -0,0 +1,11 @@
+package vcs_test
+
+import (
+	"gitea.weiker.me/rodin/review-bot/gitea"
+	"gitea.weiker.me/rodin/review-bot/vcs"
+)
+
+// Compile-time assertion: the gitea.Adapter satisfies vcs.Client.
+// (The raw gitea.Client does NOT satisfy vcs.Client due to signature differences;
+// the Adapter bridges them.)
+var _ vcs.Client = (*gitea.Adapter)(nil)

vcs/interfaces.go

@@ -0,0 +1,60 @@
+// Package vcs defines the shared VCS client interface and supporting types.
+// Platform adapters (gitea, github) implement these interfaces so the core
+// review logic can work with any VCS platform without platform-specific code.
+package vcs
+
+import "context"
+
+// PRReader can fetch pull request metadata, diffs, and changed files.
+type PRReader interface {
+	GetPullRequest(ctx context.Context, owner, repo string, number int) (*PullRequest, error)
+	GetPullRequestDiff(ctx context.Context, owner, repo string, number int) (string, error)
+	GetPullRequestFiles(ctx context.Context, owner, repo string, number int) ([]ChangedFile, error)
+	GetFileContentAtRef(ctx context.Context, owner, repo, path, ref string) (string, error)
+	GetCommitStatuses(ctx context.Context, owner, repo, sha string) ([]CommitStatus, error)
+}
+
+// FileReader can fetch file contents and list directory entries.
+type FileReader interface {
+	GetFileContent(ctx context.Context, owner, repo, path, ref string) (string, error)
+	ListContents(ctx context.Context, owner, repo, path string) ([]ContentEntry, error)
+}
+
+// Reviewer can post, list, and delete pull request reviews.
+type Reviewer interface {
+	PostReview(ctx context.Context, owner, repo string, number int, req ReviewRequest) (*Review, error)
+	ListReviews(ctx context.Context, owner, repo string, number int) ([]Review, error)
+	DeleteReview(ctx context.Context, owner, repo string, number int, reviewID int64) error
+	DismissReview(ctx context.Context, owner, repo string, number int, reviewID int64, message string) error
+}
+
+// Identity can report who the authenticated user is.
+type Identity interface {
+	GetAuthenticatedUser(ctx context.Context) (string, error)
+}
+
+// Client is the full VCS interface: PR reads, file reads, review management, and identity.
+// Platform adapters (gitea, github) implement this interface.
+type Client interface {
+	PRReader
+	FileReader
+	Reviewer
+	Identity
+}
+
+// ReviewerSelfRequester is an optional interface implemented by adapters that support
+// requesting the authenticated user as a reviewer on a pull request. This is used for
+// Gitea-specific behavior (ensuring the bot appears in required-reviewer checks).
+// Consumers should use interface assertion: if sr, ok := client.(ReviewerSelfRequester); ok { ... }
+type ReviewerSelfRequester interface {
+	RequestReviewerSelf(ctx context.Context, owner, repo string, number int, user string) error
+}
+
+// ReviewSuperseder is an optional interface implemented by adapters that support
+// marking old reviews as superseded. For Gitea this means editing the review body
+// with a link to the new review and resolving inline comments. For GitHub this
+// means dismissing old reviews.
+// Consumers should use interface assertion: if rs, ok := client.(ReviewSuperseder); ok { ... }
+type ReviewSuperseder interface {
+	SupersedeReviews(ctx context.Context, owner, repo string, prNumber int, oldReviews []Review, newReviewID int64, baseURL, sentinel string) error
+}

vcs/provider.go

@@ -0,0 +1,26 @@
+package vcs
+
+// VCSProvider identifies a VCS platform. Using a typed string instead of bare
+// strings makes provider values compiler-checkable and prevents typos from
+// silently passing validation.
+type VCSProvider string
+
+const (
+	ProviderGitea  VCSProvider = "gitea"
+	ProviderGitHub VCSProvider = "github"
+)
+
+// Valid reports whether p is a known VCS provider.
+func (p VCSProvider) Valid() bool {
+	switch p {
+	case ProviderGitea, ProviderGitHub:
+		return true
+	default:
+		return false
+	}
+}
+
+// String returns the string representation of the provider.
+func (p VCSProvider) String() string {
+	return string(p)
+}

vcs/types.go

@@ -0,0 +1,103 @@
+package vcs
+
+// ReviewEvent is the event type for a pull request review action.
+// Adapters must translate these action constants to/from platform-native values.
+// For example, Gitea uses "APPROVED" as both action and state, while GitHub
+// uses "APPROVE" for the action and returns "approved" as the state.
+type ReviewEvent string
+
+const (
+	// ReviewEventApprove approves the pull request.
+	ReviewEventApprove ReviewEvent = "APPROVE"
+	// ReviewEventRequestChanges requests changes to the pull request.
+	ReviewEventRequestChanges ReviewEvent = "REQUEST_CHANGES"
+	// ReviewEventComment posts a review comment without approval or rejection.
+	ReviewEventComment ReviewEvent = "COMMENT"
+)
+
+// BaseRef identifies the target branch of a pull request.
+type BaseRef struct {
+	Ref string `json:"ref"`
+}
+
+// HeadRef identifies the source branch and latest commit of a pull request.
+type HeadRef struct {
+	SHA string `json:"sha"`
+	Ref string `json:"ref"`
+}
+
+// UserInfo identifies a user by login name.
+type UserInfo struct {
+	Login string `json:"login"`
+}
+
+// PullRequest holds relevant PR metadata.
+type PullRequest struct {
+	Number int     `json:"number"`
+	Title  string  `json:"title"`
+	Body   string  `json:"body"`
+	Head   HeadRef `json:"head"`
+	Base   BaseRef `json:"base"`
+}
+
+// ChangedFile represents a file modified in a PR.
+type ChangedFile struct {
+	Filename string `json:"filename"`
+	Status   string `json:"status"`
+	Patch    string `json:"patch"`
+}
+
+// ContentEntry represents a file or directory entry from the contents API.
+type ContentEntry struct {
+	Name string `json:"name"`
+	Path string `json:"path"`
+	Type string `json:"type"` // "file" or "dir"
+}
+
+// CommitStatus represents a single CI status entry for a commit.
+type CommitStatus struct {
+	Status      string `json:"status"`
+	Context     string `json:"context"`
+	Description string `json:"description"`
+	TargetURL   string `json:"target_url"`
+}
+
+// Review represents a pull request review.
+type Review struct {
+	ID       int64    `json:"id"`
+	Body     string   `json:"body"`
+	User     UserInfo `json:"user"`
+	State    string   `json:"state"`
+	Stale    bool     `json:"stale"`
+	CommitID string   `json:"commit_id"`
+}
+
+// ReviewComment represents an inline comment in a review.
+// All adapters use GitHub diff-position convention:
+//   - Position is a 1-indexed offset from the @@ hunk line in the unified diff.
+//   - CommitID identifies the commit the comment is anchored to.
+//     It is optional; omit (empty string) for review-level comments that are
+//     not attached to a specific commit.
+//
+// Adapters are responsible for translating to/from platform-native formats
+// (e.g. Gitea uses line numbers; GitHub uses diff positions natively).
+type ReviewComment struct {
+	Path     string `json:"path"`
+	Position int    `json:"position"` // diff-position: 1-indexed offset from @@ hunk line
+	CommitID string `json:"commit_id"`
+	Body     string `json:"body"`
+}
+
+// ReviewRequest is the payload for posting a review.
+type ReviewRequest struct {
+	// Body is the top-level review comment.
+	Body string `json:"body"`
+	// Event is the review action (approve, request changes, or comment).
+	Event ReviewEvent `json:"event"`
+	// CommitID anchors the review to a specific commit SHA.
+	// If empty, the platform defaults to the current PR head.
+	// Adapters use this as the primary commit anchor for the review submission.
+	CommitID string `json:"commit_id,omitempty"`
+
+	Comments []ReviewComment `json:"comments,omitempty"`
+}

vcs/util.go

@@ -0,0 +1,193 @@
+package vcs
+
+import (
+	"context"
+	"fmt"
+	"strconv"
+	"strings"
+)
+
+const (
+	// maxFilesInPath is the maximum number of files GetAllFilesInPath will fetch.
+	// Prevents unbounded resource consumption on very large directory trees.
+	maxFilesInPath = 10000
+
+	// maxTotalBytesInPath is the maximum total bytes GetAllFilesInPath will accumulate.
+	// Prevents memory exhaustion when fetching large repositories.
+	maxTotalBytesInPath = 100 * 1024 * 1024 // 100 MB
+)
+
+// GetAllFilesInPath recursively fetches all file contents under a path using the
+// provided FileReader. Returns a map of filepath -> content for all files found.
+// If the path points to an empty directory, returns an empty map.
+//
+// This function uses fail-fast error handling: any error from ListContents or
+// GetFileContent aborts the entire traversal and returns the error immediately.
+// This differs from gitea.Client.GetAllFilesInPath, which logs errors and continues.
+// The fail-fast contract ensures callers can trust that a nil error means all files
+// were successfully fetched.
+//
+// Resource limits: the traversal is bounded by maxFilesInPath (file count) and
+// maxTotalBytesInPath (total accumulated bytes). The context is checked before each
+// recursive call and file fetch to respect cancellation.
+func GetAllFilesInPath(ctx context.Context, client FileReader, owner, repo, path string) (map[string]string, error) {
+	results := make(map[string]string)
+	totalBytes := 0
+
+	var walk func(string) error
+	walk = func(dir string) error {
+		if err := ctx.Err(); err != nil {
+			return fmt.Errorf("context canceled during traversal: %w", err)
+		}
+
+		entries, err := client.ListContents(ctx, owner, repo, dir)
+		if err != nil {
+			return fmt.Errorf("list contents %q: %w", dir, err)
+		}
+
+		for _, entry := range entries {
+			if err := ctx.Err(); err != nil {
+				return fmt.Errorf("context canceled during traversal: %w", err)
+			}
+
+			switch entry.Type {
+			case "file":
+				if len(results) >= maxFilesInPath {
+					return fmt.Errorf("exceeded max file count (%d) in path %q", maxFilesInPath, path)
+				}
+
+				content, err := client.GetFileContent(ctx, owner, repo, entry.Path, "")
+				if err != nil {
+					return fmt.Errorf("get file %q: %w", entry.Path, err)
+				}
+
+				totalBytes += len(content)
+				if totalBytes > maxTotalBytesInPath {
+					return fmt.Errorf("exceeded max total bytes (%d) in path %q", maxTotalBytesInPath, path)
+				}
+
+				results[entry.Path] = content
+			case "dir":
+				if err := walk(entry.Path); err != nil {
+					return err
+				}
+			}
+		}
+		return nil
+	}
+
+	if err := walk(path); err != nil {
+		return nil, err
+	}
+	return results, nil
+}
+
+// BuildLineToPositionMap parses a unified diff and returns a map of
+// filename -> (new line number -> diff position). The diff position is a
+// 1-indexed offset from the @@ hunk header line for each file.
+// Only lines that appear in the new file (context lines and additions) are mapped.
+// Deletion-only lines are not included.
+func BuildLineToPositionMap(diff string) map[string]map[int]int {
+	result := make(map[string]map[int]int)
+
+	lines := strings.Split(diff, "\n")
+	var currentFile string
+	var position int
+	var newLine int
+
+	for _, line := range lines {
+		// Detect new file in diff
+		if strings.HasPrefix(line, "+++ b/") {
+			currentFile = strings.TrimPrefix(line, "+++ b/")
+			position = 0
+			newLine = 0
+			if result[currentFile] == nil {
+				result[currentFile] = make(map[int]int)
+			}
+			continue
+		}
+
+		// Skip --- lines (old file header)
+		if strings.HasPrefix(line, "--- ") {
+			continue
+		}
+
+		// Skip diff --git lines
+		if strings.HasPrefix(line, "diff --git") {
+			continue
+		}
+
+		// Skip index lines
+		if strings.HasPrefix(line, "index ") {
+			continue
+		}
+
+		// Parse hunk headers
+		if strings.HasPrefix(line, "@@") {
+			position++
+			// Extract new file start line from @@ -a,b +c,d @@
+			newLine = parseHunkNewStart(line)
+			continue
+		}
+
+		// We need a current file to map lines
+		if currentFile == "" {
+			continue
+		}
+
+		// Skip "\ No newline at end of file" markers — these are git diff
+		// metadata and not part of the file content.
+		if strings.HasPrefix(line, `\`) {
+			continue
+		}
+
+		// Process diff content lines
+		if strings.HasPrefix(line, "+") {
+			position++
+			result[currentFile][newLine] = position
+			newLine++
+		} else if strings.HasPrefix(line, "-") {
+			position++
+			// Deletion lines don't map to new line numbers
+		} else if strings.HasPrefix(line, " ") {
+			// Context line (space-prefixed).
+			// Only map if position > 0, which means we've seen a hunk header.
+			// Lines before the first hunk header (position == 0) are not part
+			// of any diff hunk and should be skipped.
+			if position > 0 {
+				position++
+				result[currentFile][newLine] = position
+				newLine++
+			}
+		}
+	}
+
+	return result
+}
+
+// parseHunkNewStart extracts the new-file starting line number from a hunk header.
+// Format: @@ -old_start[,old_count] +new_start[,new_count] @@
+func parseHunkNewStart(hunkLine string) int {
+	// Find the +N part
+	plusIdx := strings.Index(hunkLine, "+")
+	if plusIdx < 0 {
+		return 1
+	}
+	rest := hunkLine[plusIdx+1:]
+
+	// Find the end of the number (first non-digit after +)
+	endIdx := 0
+	for endIdx < len(rest) && rest[endIdx] >= '0' && rest[endIdx] <= '9' {
+		endIdx++
+	}
+
+	if endIdx == 0 {
+		return 1
+	}
+
+	n, err := strconv.Atoi(rest[:endIdx])
+	if err != nil {
+		return 1
+	}
+	return n
+}

vcs/util_test.go

@@ -0,0 +1,331 @@
+package vcs_test
+
+import (
+	"context"
+	"fmt"
+	"strings"
+	"testing"
+
+	"gitea.weiker.me/rodin/review-bot/vcs"
+)
+
+// mockFileReader implements vcs.FileReader for testing.
+type mockFileReader struct {
+	contents map[string][]vcs.ContentEntry // path -> entries
+	files    map[string]string             // path -> content
+}
+
+func (m *mockFileReader) GetFileContent(ctx context.Context, owner, repo, path, ref string) (string, error) {
+	content, ok := m.files[path]
+	if !ok {
+		return "", fmt.Errorf("HTTP 404: file not found: %s", path)
+	}
+	return content, nil
+}
+
+func (m *mockFileReader) ListContents(ctx context.Context, owner, repo, path string) ([]vcs.ContentEntry, error) {
+	entries, ok := m.contents[path]
+	if !ok {
+		return nil, fmt.Errorf("HTTP 404: path not found: %s", path)
+	}
+	return entries, nil
+}
+
+func TestGetAllFilesInPath(t *testing.T) {
+	ctx := context.Background()
+
+	t.Run("empty directory", func(t *testing.T) {
+		client := &mockFileReader{
+			contents: map[string][]vcs.ContentEntry{
+				"src": {},
+			},
+		}
+		result, err := vcs.GetAllFilesInPath(ctx, client, "owner", "repo", "src")
+		if err != nil {
+			t.Fatalf("unexpected error: %v", err)
+		}
+		if len(result) != 0 {
+			t.Errorf("expected empty map, got %d entries", len(result))
+		}
+	})
+
+	t.Run("flat directory", func(t *testing.T) {
+		client := &mockFileReader{
+			contents: map[string][]vcs.ContentEntry{
+				"src": {
+					{Name: "main.go", Path: "src/main.go", Type: "file"},
+					{Name: "util.go", Path: "src/util.go", Type: "file"},
+				},
+			},
+			files: map[string]string{
+				"src/main.go": "package main",
+				"src/util.go": "package main\n// util",
+			},
+		}
+		result, err := vcs.GetAllFilesInPath(ctx, client, "owner", "repo", "src")
+		if err != nil {
+			t.Fatalf("unexpected error: %v", err)
+		}
+		if len(result) != 2 {
+			t.Fatalf("expected 2 files, got %d", len(result))
+		}
+		if result["src/main.go"] != "package main" {
+			t.Errorf("main.go content = %q", result["src/main.go"])
+		}
+		if result["src/util.go"] != "package main\n// util" {
+			t.Errorf("util.go content = %q", result["src/util.go"])
+		}
+	})
+
+	t.Run("nested directories", func(t *testing.T) {
+		client := &mockFileReader{
+			contents: map[string][]vcs.ContentEntry{
+				"src": {
+					{Name: "main.go", Path: "src/main.go", Type: "file"},
+					{Name: "pkg", Path: "src/pkg", Type: "dir"},
+				},
+				"src/pkg": {
+					{Name: "lib.go", Path: "src/pkg/lib.go", Type: "file"},
+					{Name: "sub", Path: "src/pkg/sub", Type: "dir"},
+				},
+				"src/pkg/sub": {
+					{Name: "deep.go", Path: "src/pkg/sub/deep.go", Type: "file"},
+				},
+			},
+			files: map[string]string{
+				"src/main.go":         "package main",
+				"src/pkg/lib.go":      "package pkg",
+				"src/pkg/sub/deep.go": "package sub",
+			},
+		}
+		result, err := vcs.GetAllFilesInPath(ctx, client, "owner", "repo", "src")
+		if err != nil {
+			t.Fatalf("unexpected error: %v", err)
+		}
+		if len(result) != 3 {
+			t.Fatalf("expected 3 files, got %d", len(result))
+		}
+		if result["src/main.go"] != "package main" {
+			t.Errorf("main.go content = %q", result["src/main.go"])
+		}
+		if result["src/pkg/lib.go"] != "package pkg" {
+			t.Errorf("lib.go content = %q", result["src/pkg/lib.go"])
+		}
+		if result["src/pkg/sub/deep.go"] != "package sub" {
+			t.Errorf("deep.go content = %q", result["src/pkg/sub/deep.go"])
+		}
+	})
+
+	t.Run("mixed files and dirs", func(t *testing.T) {
+		client := &mockFileReader{
+			contents: map[string][]vcs.ContentEntry{
+				"root": {
+					{Name: "README.md", Path: "root/README.md", Type: "file"},
+					{Name: "docs", Path: "root/docs", Type: "dir"},
+					{Name: "config.yaml", Path: "root/config.yaml", Type: "file"},
+				},
+				"root/docs": {
+					{Name: "guide.md", Path: "root/docs/guide.md", Type: "file"},
+				},
+			},
+			files: map[string]string{
+				"root/README.md":     "# Hello",
+				"root/config.yaml":   "key: value",
+				"root/docs/guide.md": "## Guide",
+			},
+		}
+		result, err := vcs.GetAllFilesInPath(ctx, client, "owner", "repo", "root")
+		if err != nil {
+			t.Fatalf("unexpected error: %v", err)
+		}
+		if len(result) != 3 {
+			t.Fatalf("expected 3 files, got %d", len(result))
+		}
+		if result["root/README.md"] != "# Hello" {
+			t.Errorf("README content = %q", result["root/README.md"])
+		}
+		if result["root/docs/guide.md"] != "## Guide" {
+			t.Errorf("guide content = %q", result["root/docs/guide.md"])
+		}
+	})
+}
+
+func TestBuildLineToPositionMap(t *testing.T) {
+	t.Run("single hunk", func(t *testing.T) {
+		diff := "diff --git a/file.go b/file.go\nindex abc..def 100644\n--- a/file.go\n+++ b/file.go\n@@ -1,3 +1,4 @@\n package main\n \n+// new comment\n func main() {}\n"
+		result := vcs.BuildLineToPositionMap(diff)
+		fileMap, ok := result["file.go"]
+		if !ok {
+			t.Fatal("expected file.go in result")
+		}
+		// Hunk header @@ is position 1
+		// Line 1: " package main" -> position 2
+		if fileMap[1] != 2 {
+			t.Errorf("line 1 position = %d, want 2", fileMap[1])
+		}
+		// Line 2: " " (context) -> position 3
+		if fileMap[2] != 3 {
+			t.Errorf("line 2 position = %d, want 3", fileMap[2])
+		}
+		// Line 3: "+// new comment" -> position 4
+		if fileMap[3] != 4 {
+			t.Errorf("line 3 position = %d, want 4", fileMap[3])
+		}
+		// Line 4: " func main() {}" -> position 5
+		if fileMap[4] != 5 {
+			t.Errorf("line 4 position = %d, want 5", fileMap[4])
+		}
+	})
+
+	t.Run("multi hunk", func(t *testing.T) {
+		diff := "diff --git a/file.go b/file.go\n--- a/file.go\n+++ b/file.go\n@@ -1,3 +1,3 @@\n package main\n \n-// old\n+// new\n@@ -10,3 +10,4 @@\n func foo() {\n+\t// added\n \treturn\n }\n"
+		result := vcs.BuildLineToPositionMap(diff)
+		fileMap, ok := result["file.go"]
+		if !ok {
+			t.Fatal("expected file.go in result")
+		}
+		// First hunk: @@ is position 1
+		// Line 1: " package main" -> position 2
+		if fileMap[1] != 2 {
+			t.Errorf("line 1 position = %d, want 2", fileMap[1])
+		}
+		// Line 3: "+// new" -> position 5 (after " ", "-// old" at pos 3,4)
+		if fileMap[3] != 5 {
+			t.Errorf("line 3 position = %d, want 5", fileMap[3])
+		}
+		// Second hunk: @@ is position 6
+		// Line 10: " func foo() {" -> position 7
+		if fileMap[10] != 7 {
+			t.Errorf("line 10 position = %d, want 7", fileMap[10])
+		}
+		// Line 11: "+\t// added" -> position 8
+		if fileMap[11] != 8 {
+			t.Errorf("line 11 position = %d, want 8", fileMap[11])
+		}
+	})
+
+	t.Run("deletion lines not in map", func(t *testing.T) {
+		diff := "diff --git a/file.go b/file.go\n--- a/file.go\n+++ b/file.go\n@@ -1,4 +1,3 @@\n package main\n \n-// deleted line\n func main() {}\n"
+		result := vcs.BuildLineToPositionMap(diff)
+		fileMap, ok := result["file.go"]
+		if !ok {
+			t.Fatal("expected file.go in result")
+		}
+		// Line 1: " package main" -> position 2
+		if fileMap[1] != 2 {
+			t.Errorf("line 1 position = %d, want 2", fileMap[1])
+		}
+		// Line 3 in new file: " func main() {}" -> position 5 (after deletion at pos 4)
+		if fileMap[3] != 5 {
+			t.Errorf("line 3 position = %d, want 5", fileMap[3])
+		}
+		// Should only have 3 entries (lines 1, 2, 3 of new file)
+		if len(fileMap) != 3 {
+			t.Errorf("expected 3 mapped lines, got %d: %v", len(fileMap), fileMap)
+		}
+	})
+
+	t.Run("multiple files", func(t *testing.T) {
+		diff := "diff --git a/a.go b/a.go\n--- a/a.go\n+++ b/a.go\n@@ -1,2 +1,3 @@\n package a\n \n+// file a\ndiff --git a/b.go b/b.go\n--- a/b.go\n+++ b/b.go\n@@ -1,2 +1,3 @@\n package b\n \n+// file b\n"
+		result := vcs.BuildLineToPositionMap(diff)
+		if len(result) != 2 {
+			t.Fatalf("expected 2 files, got %d", len(result))
+		}
+		aMap, ok := result["a.go"]
+		if !ok {
+			t.Fatal("expected a.go in result")
+		}
+		bMap, ok := result["b.go"]
+		if !ok {
+			t.Fatal("expected b.go in result")
+		}
+		// a.go line 3: "+// file a" -> position 4
+		if aMap[3] != 4 {
+			t.Errorf("a.go line 3 position = %d, want 4", aMap[3])
+		}
+		// b.go line 3: "+// file b" -> position 4
+		if bMap[3] != 4 {
+			t.Errorf("b.go line 3 position = %d, want 4", bMap[3])
+		}
+	})
+}
+
+func TestGetAllFilesInPath_ErrorPropagation(t *testing.T) {
+	ctx := context.Background()
+
+	t.Run("ListContents error propagates", func(t *testing.T) {
+		client := &mockFileReader{
+			contents: map[string][]vcs.ContentEntry{
+				// "src" not in map, so ListContents will fail
+			},
+		}
+		_, err := vcs.GetAllFilesInPath(ctx, client, "owner", "repo", "src")
+		if err == nil {
+			t.Fatal("expected error, got nil")
+		}
+		if !strings.Contains(err.Error(), "list contents") {
+			t.Errorf("expected error about list contents, got: %v", err)
+		}
+	})
+
+	t.Run("GetFileContent error propagates", func(t *testing.T) {
+		client := &mockFileReader{
+			contents: map[string][]vcs.ContentEntry{
+				"src": {
+					{Name: "main.go", Path: "src/main.go", Type: "file"},
+				},
+			},
+			files: map[string]string{
+				// "src/main.go" not in files map, so GetFileContent will fail
+			},
+		}
+		_, err := vcs.GetAllFilesInPath(ctx, client, "owner", "repo", "src")
+		if err == nil {
+			t.Fatal("expected error, got nil")
+		}
+		if !strings.Contains(err.Error(), "get file") {
+			t.Errorf("expected error about get file, got: %v", err)
+		}
+	})
+
+	t.Run("nested ListContents error propagates", func(t *testing.T) {
+		client := &mockFileReader{
+			contents: map[string][]vcs.ContentEntry{
+				"src": {
+					{Name: "pkg", Path: "src/pkg", Type: "dir"},
+				},
+				// "src/pkg" not in map, so recursive ListContents will fail
+			},
+		}
+		_, err := vcs.GetAllFilesInPath(ctx, client, "owner", "repo", "src")
+		if err == nil {
+			t.Fatal("expected error, got nil")
+		}
+		if !strings.Contains(err.Error(), "list contents") {
+			t.Errorf("expected error about list contents, got: %v", err)
+		}
+	})
+
+	t.Run("canceled context propagates", func(t *testing.T) {
+		ctx, cancel := context.WithCancel(context.Background())
+		cancel() // Cancel immediately
+
+		client := &mockFileReader{
+			contents: map[string][]vcs.ContentEntry{
+				"src": {
+					{Name: "main.go", Path: "src/main.go", Type: "file"},
+				},
+			},
+			files: map[string]string{
+				"src/main.go": "package main",
+			},
+		}
+		_, err := vcs.GetAllFilesInPath(ctx, client, "owner", "repo", "src")
+		if err == nil {
+			t.Fatal("expected error from canceled context, got nil")
+		}
+		if !strings.Contains(err.Error(), "context canceled") {
+			t.Errorf("expected context cancellation error, got: %v", err)
+		}
+	})
+}