docs: add review update strategy with state transition diagram

Explains the edit-in-place approach, state transition rules, worst-wins
escalation, and inline comment lifecycle. Includes a Mermaid state
diagram for visual reference.

.gitea/actions/review/action.yml

@@ -34,6 +34,10 @@ inputs:
   llm-model:
     description: 'LLM model name'
     required: true
+  llm-provider:
+    description: 'LLM API provider: openai or anthropic (default openai)'
+    required: false
+    default: 'openai' 
   conventions-file:
     description: 'Path to conventions file in the repo (e.g. CLAUDE.md)'
     required: false
@@ -62,6 +66,14 @@ 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: ''
 
 runs:
   using: 'composite'
@@ -140,6 +152,9 @@ runs:
         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: ${{ inputs.system-prompt-file }}
       run: |
         ARGS=""
         if [ "${{ inputs.dry-run }}" = "true" ]; then

.gitea/workflows/ci.yml

@@ -32,6 +32,10 @@ jobs:
           - name: gpt
             token_secret: GPT_REVIEW_TOKEN
             model: gpt-4.1
+          - name: security
+            token_secret: SONNET_REVIEW_TOKEN
+            model: gpt-5
+            system_prompt_file: SECURITY_REVIEW.md
     steps:
       - uses: actions/checkout@v4
       - uses: actions/setup-go@v5
@@ -44,6 +48,7 @@ jobs:
           GITEA_REPO: ${{ github.repository }}
           PR_NUMBER: ${{ github.event.pull_request.number }}
           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 }}
@@ -51,4 +56,5 @@ jobs:
           PATTERNS_REPO: "rodin/go-patterns"
           PATTERNS_FILES: "README.md,patterns/"
           LLM_TIMEOUT: "600"
+          SYSTEM_PROMPT_FILE: ${{ matrix.system_prompt_file }}
         run: ./review-bot

README.md

@@ -1,17 +1,242 @@
 # 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
+- **Multi-provider**: OpenAI-compatible and Anthropic Messages API
-- Sends context-rich prompts to any OpenAI-compatible LLM
+- **Context-aware**: Fetches full file content, conventions, language patterns, CI status
-- Parses structured JSON review responses
+- **Smart budget**: Automatically trims context to fit model token limits
-- Posts formatted reviews (APPROVE / REQUEST_CHANGES) back to Gitea
+- **Idempotent reviews**: Posts new review, then cleans up stale ones (one review per bot)
-- Supports custom coding conventions via repo files
+- **Custom prompts**: Load additional instructions from a file (e.g. security-focused review)
-- Zero external dependencies — Go stdlib only
+- **Zero dependencies**: Go stdlib 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
+```
+
+## 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` | Yes | — | LLM API base URL |
+| `llm-api-key` | Yes | — | LLM API key |
+| `llm-model` | Yes | — | Model name |
+| `llm-provider` | No | `openai` | API provider: `openai` or `anthropic` |
+| `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 |
+| `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 |
+
+## 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 \
@@ -19,71 +244,74 @@ 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 \
+  --llm-model gpt-4.1 \
-  --reviewer-name "Sonnet" \
+  --conventions-file CONVENTIONS.md
-  --conventions-file CONVENTIONS.md \
-  --dry-run
 ```
 
 ## Environment Variables
 
-All flags can be set via environment variables:
+All flags have environment variable equivalents:
 
-| Flag | Env Var | Required | Description |
+| Flag | Env Var |
-|------|---------|----------|-------------|
+|------|---------|
-| `--gitea-url` | `GITEA_URL` | Yes | Gitea instance base URL |
+| `--gitea-url` | `GITEA_URL` |
-| `--repo` | `GITEA_REPO` | Yes | Repository in `owner/name` format |
+| `--repo` | `GITEA_REPO` |
-| `--pr` | `PR_NUMBER` | Yes | Pull request number |
+| `--pr` | `PR_NUMBER` |
-| `--reviewer-token` | `REVIEWER_TOKEN` | Yes | Gitea API token for posting reviews |
+| `--reviewer-token` | `REVIEWER_TOKEN` |
-| `--llm-base-url` | `LLM_BASE_URL` | Yes | OpenAI-compatible API base URL |
+| `--reviewer-name` | `REVIEWER_NAME` |
-| `--llm-api-key` | `LLM_API_KEY` | Yes | LLM API key |
+| `--llm-base-url` | `LLM_BASE_URL` |
-| `--llm-model` | `LLM_MODEL` | Yes | Model identifier |
+| `--llm-api-key` | `LLM_API_KEY` |
-| `--reviewer-name` | `REVIEWER_NAME` | No | Display name in review footer |
+| `--llm-model` | `LLM_MODEL` |
-| `--conventions-file` | `CONVENTIONS_FILE` | No | Path to conventions file in repo |
+| `--llm-provider` | `LLM_PROVIDER` |
-| `--dry-run` | — | No | Print review to stdout instead of posting |
+| `--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):
+### Token Scopes Required
-   - `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
 
-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 |
 
-4. On every PR, the bot will:
+No `read:user` scope needed — the bot identifies itself from the review response.
-   - Run tests and vet
-   - Build review-bot
-   - Post reviews from each configured LLM reviewer
 
 ## Development
 
 ```bash
-# Run tests
+go test ./...        # Unit tests
-go test ./...
+go vet ./...         # Static analysis
-
-# Run vet
-go vet ./...
-
-# Build
 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
+cmd/review-bot/     CLI entrypoint + orchestration
-gitea/              Gitea API client
+gitea/              Gitea API client (reviews, PRs, files)
-llm/                OpenAI-compatible LLM client
+llm/                Multi-provider LLM client (OpenAI + Anthropic)
 review/             Prompt building, response parsing, formatting
+budget/             Token estimation + context trimming
 ```
 
 ## License

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.

cmd/review-bot/main.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"log"
 	"os"
+	"path/filepath"
 	"strconv"
 	"strings"
 	"time"
@@ -30,11 +31,14 @@ func main() {
 	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")
+	updateExisting := flag.Bool("update-existing", envOrDefaultBool("UPDATE_EXISTING", true), "Delete previous review from same bot before posting (default true)")
 	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 or anthropic")
 
 	flag.Parse()
 
@@ -53,6 +57,11 @@ func main() {
 		os.Exit(1)
 	}
 
+	// Validate reviewer-name: only safe characters allowed in sentinel
+	if err := validateReviewerName(*reviewerName); err != nil {
+		log.Fatalf("%v", err)
+	}
+
 	// Parse repo owner/name
 	parts := strings.SplitN(*repo, "/", 2)
 	if len(parts) != 2 {
@@ -75,6 +84,12 @@ func main() {
 	if *llmTemp > 0 {
 		llmClient.WithTemperature(*llmTemp)
 	}
+	switch llm.Provider(*llmProvider) {
+	case llm.ProviderOpenAI, llm.ProviderAnthropic:
+		llmClient.WithProvider(llm.Provider(*llmProvider))
+	default:
+		log.Fatalf("Invalid --llm-provider %q, must be openai or anthropic", *llmProvider)
+	}
 	if *llmTimeout > 0 {
 		llmClient.WithTimeout(time.Duration(*llmTimeout) * time.Second)
 	}
@@ -142,9 +157,45 @@ func main() {
 		log.Printf("Loaded patterns from %s (%d bytes)", *patternsRepo, len(patterns))
 	}
 
+	// Step 6b: Load additional system prompt if specified
+	additionalPrompt := ""
+	if *systemPromptFile != "" {
+		workspace := os.Getenv("GITHUB_WORKSPACE")
+		if workspace == "" {
+			workspace, _ = os.Getwd()
+		}
+		absWorkspace, err := filepath.Abs(workspace)
+		if err != nil {
+			log.Fatalf("Failed to resolve workspace path: %v", err)
+		}
+		promptPath := filepath.Join(absWorkspace, *systemPromptFile)
+		promptPath = filepath.Clean(promptPath)
+		if !strings.HasPrefix(promptPath, absWorkspace+string(filepath.Separator)) && promptPath != absWorkspace {
+			log.Fatalf("system-prompt-file resolves outside workspace (got %q, workspace %q)", promptPath, absWorkspace)
+		}
+		// Resolve symlinks and re-validate to prevent symlink traversal
+		resolvedPath, err := filepath.EvalSymlinks(promptPath)
+		if err != nil {
+			log.Fatalf("Failed to resolve system prompt file %q: %v", promptPath, err)
+		}
+		if !strings.HasPrefix(resolvedPath, absWorkspace+string(filepath.Separator)) && resolvedPath != absWorkspace {
+			log.Fatalf("system-prompt-file symlink resolves outside workspace (got %q, workspace %q)", resolvedPath, absWorkspace)
+		}
+		data, err := os.ReadFile(resolvedPath)
+		if err != nil {
+			log.Fatalf("Failed to read system prompt file %q: %v", promptPath, err)
+		}
+		additionalPrompt = string(data)
+		log.Printf("Loaded system prompt file: %s (%d bytes)", *systemPromptFile, len(additionalPrompt))
+	}
+
 	// Step 7: Budget-aware prompt assembly
+	systemBase := review.BuildSystemBase()
+	if additionalPrompt != "" {
+		systemBase += "\n\n## Additional Review Instructions\n\n" + additionalPrompt
+	}
 	sections := budget.Sections{
-		SystemBase:  review.BuildSystemBase(),
+		SystemBase:  systemBase,
 		Patterns:    patterns,
 		Conventions: conventions,
 		FileContext: fileContext,
@@ -188,11 +239,112 @@ func main() {
 		return
 	}
 
+	sentinel := fmt.Sprintf("<!-- review-bot:%s -->", *reviewerName)
+
+	// Map findings to inline comments for lines present in the diff
+	diffRanges := gitea.ParseDiffNewLines(diff)
+	var inlineComments []gitea.ReviewComment
+	for _, f := range result.Findings {
+		if f.File != "" && f.Line > 0 && diffRanges.Contains(f.File, f.Line) {
+			inlineComments = append(inlineComments, gitea.ReviewComment{
+				Path:        f.File,
+				NewPosition: int64(f.Line),
+				Body:        fmt.Sprintf("**[%s]** %s", f.Severity, f.Finding),
+			})
+		}
+	}
+	if len(inlineComments) > 0 {
+		log.Printf("Attaching %d inline comments", len(inlineComments))
+	}
+
+	// --- Review update strategy ---
+	// 1. No existing review → POST new
+	// 2. Existing review, same state → PATCH body in place (preserves threads)
+	// 3. Existing review, state change → PATCH old to "Superseded", POST new
+	if *updateExisting && *reviewerName != "" {
+		existingReviews, err := giteaClient.ListReviews(ctx, owner, repoName, prNumber)
+		if err != nil {
+			log.Printf("Warning: could not list existing reviews: %v", err)
+		} else {
+			// Worst-wins: escalate if a sibling blocks (need own login from existing review)
+			ownLogin := ""
+			existing := findOwnReview(existingReviews, sentinel)
+			if existing != nil {
+				ownLogin = existing.User.Login
+			}
+			if event == "APPROVED" && shouldEscalate(existingReviews, 0, ownLogin, sentinel) {
+				log.Printf("Sibling review has REQUEST_CHANGES; escalating to REQUEST_CHANGES")
+				event = "REQUEST_CHANGES"
+			}
+
+			if existing != nil {
+				if reviewUnchanged(existingReviews, reviewBody, event, sentinel) {
+					log.Printf("Review unchanged from previous run; skipping to preserve threads")
+					return
+				}
+
+				// Same state → PATCH in place
+				if existing.State == event {
+					commentID, err := giteaClient.GetTimelineReviewCommentID(ctx, owner, repoName, prNumber, sentinel)
+					if err != nil {
+						log.Printf("Warning: could not find review comment ID, falling back to new post: %v", err)
+					} else {
+						if err := giteaClient.EditComment(ctx, owner, repoName, commentID, reviewBody); err != nil {
+							log.Printf("Warning: could not edit review, falling back to new post: %v", err)
+						} else {
+							log.Printf("Review updated in place (comment_id=%d)", commentID)
+							return
+						}
+					}
+				} else {
+					// State change → mark old as superseded, post new below
+					commentID, err := giteaClient.GetTimelineReviewCommentID(ctx, owner, repoName, prNumber, sentinel)
+					if err != nil {
+						log.Printf("Warning: could not find old review comment ID: %v", err)
+					} else {
+						supersededBody := fmt.Sprintf("~~*This review has been superseded by a newer review below.*~~\n\n%s", sentinel)
+						if err := giteaClient.EditComment(ctx, owner, repoName, commentID, supersededBody); err != nil {
+							log.Printf("Warning: could not mark old review as superseded: %v", err)
+						} else {
+							log.Printf("Marked old review as superseded (state was %s, now %s)", existing.State, event)
+						}
+					}
+				}
+			}
+		}
+	}
+
+	// POST new review (first run, or state transition fallthrough)
 	log.Printf("Posting review (event=%s)...", event)
-	if err := giteaClient.PostReview(ctx, owner, repoName, prNumber, event, reviewBody); err != nil {
+	posted, err := giteaClient.PostReview(ctx, owner, repoName, prNumber, event, reviewBody, inlineComments)
+	if err != nil {
 		log.Fatalf("Failed to post review: %v", err)
 	}
-	log.Printf("Review posted successfully!")
+	log.Printf("Review posted (id=%d, user=%s)", posted.ID, posted.User.Login)
+
+	// Post-posting escalation: if we just posted APPROVED but a sibling
+	// from the same user has REQUEST_CHANGES, mark ours as superseded and
+	// re-post as REQUEST_CHANGES. This handles the first-run case where
+	// we don't know our login until after posting.
+	if event == "APPROVED" && *updateExisting && *reviewerName != "" {
+		reviews, err := giteaClient.ListReviews(ctx, owner, repoName, prNumber)
+		if err == nil && shouldEscalate(reviews, posted.ID, posted.User.Login, sentinel) {
+			log.Printf("Post-posting escalation: sibling has REQUEST_CHANGES")
+			// Mark our just-posted review as superseded
+			commentID, err := giteaClient.GetTimelineReviewCommentID(ctx, owner, repoName, prNumber, sentinel)
+			if err == nil {
+				supersededBody := fmt.Sprintf("~~*This review has been superseded by a newer review below.*~~\n\n%s", sentinel)
+				giteaClient.EditComment(ctx, owner, repoName, commentID, supersededBody)
+			}
+			// Re-post as REQUEST_CHANGES
+			_, err = giteaClient.PostReview(ctx, owner, repoName, prNumber, "REQUEST_CHANGES", reviewBody, inlineComments)
+			if err != nil {
+				log.Printf("Warning: could not re-post as REQUEST_CHANGES: %v", err)
+			} else {
+				log.Printf("Review escalated to REQUEST_CHANGES")
+			}
+		}
+	}
 }
 
 // fetchFileContext fetches the full content of modified files from the PR branch.
@@ -326,3 +478,73 @@ func envOrDefaultInt(key string, defaultVal int) int {
 	}
 	return defaultVal
 }
+
+func envOrDefaultBool(key string, defaultVal bool) bool {
+	v := strings.TrimSpace(strings.ToLower(os.Getenv(key)))
+	if v == "" {
+		return defaultVal
+	}
+	return v == "true" || v == "1" || v == "yes"
+}
+
+// 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
+}
+
+// shouldEscalate checks if any sibling bot review from the same user
+// (different sentinel, same token) has REQUEST_CHANGES.
+// ownLogin is the bot user login; if empty, escalation check is skipped.
+// postedID is excluded from consideration (0 means no exclusion needed).
+func shouldEscalate(reviews []gitea.Review, postedID int64, ownLogin, ownSentinel string) bool {
+	if ownLogin == "" {
+		return false
+	}
+	for _, r := range reviews {
+		if r.ID == postedID || r.Stale {
+			continue
+		}
+		// Sibling = same user, has a review-bot sentinel, but not OUR sentinel
+		if r.User.Login == ownLogin && r.State == "REQUEST_CHANGES" && strings.Contains(r.Body, "<!-- review-bot:") && !strings.Contains(r.Body, ownSentinel) {
+			return true
+		}
+	}
+	return false
+}
+
+// reviewUnchanged checks if an existing review with the same sentinel
+// already has identical body and state. Returns true if a re-post would
+// produce the same result (skip to preserve conversation threads).
+func reviewUnchanged(reviews []gitea.Review, newBody, newEvent, sentinel string) bool {
+	for _, r := range reviews {
+		if r.Stale {
+			continue
+		}
+		if !strings.Contains(r.Body, sentinel) {
+			continue
+		}
+		if r.State == newEvent && r.Body == newBody {
+			return true
+		}
+	}
+	return false
+}
+
+// findOwnReview locates a review matching the given sentinel in its body.
+func findOwnReview(reviews []gitea.Review, sentinel string) *gitea.Review {
+	for i := range reviews {
+		if strings.Contains(reviews[i].Body, sentinel) {
+			return &reviews[i]
+		}
+	}
+	return nil
+}

cmd/review-bot/main_test.go

@@ -0,0 +1,290 @@
+package main
+
+import (
+	"testing"
+
+	"gitea.weiker.me/rodin/review-bot/gitea"
+)
+
+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 makeReview(id int64, login, state string, stale bool, body string) gitea.Review {
+	r := gitea.Review{
+		ID:    id,
+		Body:  body,
+		State: state,
+		Stale: stale,
+	}
+	r.User.Login = login
+	return r
+}
+
+func TestShouldEscalate(t *testing.T) {
+	tests := []struct {
+		name        string
+		reviews     []gitea.Review
+		postedID    int64
+		ownLogin    string
+
+		ownSentinel string
+		want        bool
+	}{
+		{
+			name:        "no reviews",
+			reviews:     nil,
+			postedID:    100,
+			ownLogin:    "bot",
+			ownSentinel: "<!-- review-bot:sonnet -->",
+			want:        false,
+		},
+		{
+			name: "sibling same user has REQUEST_CHANGES",
+			reviews: []gitea.Review{
+				makeReview(101, "bot", "REQUEST_CHANGES", false, "bad\n<!-- review-bot:security -->"),
+			},
+			postedID:    100,
+			ownLogin:    "bot",
+			ownSentinel: "<!-- review-bot:sonnet -->",
+			want:        true,
+		},
+		{
+			name: "sibling different user has REQUEST_CHANGES (should NOT escalate)",
+			reviews: []gitea.Review{
+				makeReview(101, "other-bot", "REQUEST_CHANGES", false, "bad\n<!-- review-bot:gpt -->"),
+			},
+			postedID:    100,
+			ownLogin:    "bot",
+			ownSentinel: "<!-- review-bot:sonnet -->",
+			want:        false,
+		},
+		{
+			name: "same user REQUEST_CHANGES but stale (should NOT escalate)",
+			reviews: []gitea.Review{
+				makeReview(101, "bot", "REQUEST_CHANGES", true, "old\n<!-- review-bot:security -->"),
+			},
+			postedID:    100,
+			ownLogin:    "bot",
+			ownSentinel: "<!-- review-bot:sonnet -->",
+			want:        false,
+		},
+		{
+			name: "same user same sentinel (own stale review, should NOT escalate)",
+			reviews: []gitea.Review{
+				makeReview(101, "bot", "REQUEST_CHANGES", false, "old\n<!-- review-bot:sonnet -->"),
+			},
+			postedID:    100,
+			ownLogin:    "bot",
+			ownSentinel: "<!-- review-bot:sonnet -->",
+			want:        false,
+		},
+		{
+			name: "same user APPROVED sibling (should NOT escalate)",
+			reviews: []gitea.Review{
+				makeReview(101, "bot", "APPROVED", false, "good\n<!-- review-bot:security -->"),
+			},
+			postedID:    100,
+			ownLogin:    "bot",
+			ownSentinel: "<!-- review-bot:sonnet -->",
+			want:        false,
+		},
+		{
+			name: "human REQUEST_CHANGES no sentinel (should NOT escalate)",
+			reviews: []gitea.Review{
+				makeReview(101, "bot", "REQUEST_CHANGES", false, "please fix this"),
+			},
+			postedID:    100,
+			ownLogin:    "bot",
+			ownSentinel: "<!-- review-bot:sonnet -->",
+			want:        false,
+		},
+		{
+			name: "skip own posted ID",
+			reviews: []gitea.Review{
+				makeReview(100, "bot", "REQUEST_CHANGES", false, "x\n<!-- review-bot:security -->"),
+			},
+			postedID:    100,
+			ownLogin:    "bot",
+			ownSentinel: "<!-- review-bot:sonnet -->",
+			want:        false,
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			got := shouldEscalate(tc.reviews, tc.postedID, tc.ownLogin, tc.ownSentinel)
+			if got != tc.want {
+				t.Errorf("shouldEscalate() = %v, want %v", got, tc.want)
+			}
+		})
+	}
+}
+
+func TestReviewUnchanged(t *testing.T) {
+	tests := []struct {
+		name     string
+		existing []gitea.Review
+		newBody  string
+		newEvent string
+		sentinel string
+		want     bool
+	}{
+		{
+			name:     "no existing review",
+			existing: nil,
+			newBody:  "new review",
+			newEvent: "APPROVED",
+			sentinel: "<!-- review-bot:sonnet -->",
+			want:     false,
+		},
+		{
+			name: "identical body and state",
+			existing: []gitea.Review{
+				makeReview(100, "bot", "APPROVED", false, "same body\n<!-- review-bot:sonnet -->"),
+			},
+			newBody:  "same body\n<!-- review-bot:sonnet -->",
+			newEvent: "APPROVED",
+			sentinel: "<!-- review-bot:sonnet -->",
+			want:     true,
+		},
+		{
+			name: "same body but different state",
+			existing: []gitea.Review{
+				makeReview(100, "bot", "APPROVED", false, "body\n<!-- review-bot:sonnet -->"),
+			},
+			newBody:  "body\n<!-- review-bot:sonnet -->",
+			newEvent: "REQUEST_CHANGES",
+			sentinel: "<!-- review-bot:sonnet -->",
+			want:     false,
+		},
+		{
+			name: "different body same state",
+			existing: []gitea.Review{
+				makeReview(100, "bot", "APPROVED", false, "old body\n<!-- review-bot:sonnet -->"),
+			},
+			newBody:  "new body\n<!-- review-bot:sonnet -->",
+			newEvent: "APPROVED",
+			sentinel: "<!-- review-bot:sonnet -->",
+			want:     false,
+		},
+		{
+			name: "stale review with same body (should still post)",
+			existing: []gitea.Review{
+				makeReview(100, "bot", "APPROVED", true, "same\n<!-- review-bot:sonnet -->"),
+			},
+			newBody:  "same\n<!-- review-bot:sonnet -->",
+			newEvent: "APPROVED",
+			sentinel: "<!-- review-bot:sonnet -->",
+			want:     false,
+		},
+		{
+			name: "different sentinel (not our review)",
+			existing: []gitea.Review{
+				makeReview(100, "bot", "APPROVED", false, "body\n<!-- review-bot:gpt -->"),
+			},
+			newBody:  "body\n<!-- review-bot:sonnet -->",
+			newEvent: "APPROVED",
+			sentinel: "<!-- review-bot:sonnet -->",
+			want:     false,
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			got := reviewUnchanged(tc.existing, tc.newBody, tc.newEvent, tc.sentinel)
+			if got != tc.want {
+				t.Errorf("reviewUnchanged() = %v, want %v", got, tc.want)
+			}
+		})
+	}
+}
+
+func TestFindOwnReview(t *testing.T) {
+	tests := []struct {
+		name     string
+		reviews  []gitea.Review
+		sentinel string
+		wantID   int64
+		wantNil  bool
+	}{
+		{
+			name:     "no reviews",
+			reviews:  nil,
+			sentinel: "<!-- review-bot:sonnet -->",
+			wantNil:  true,
+		},
+		{
+			name: "found by sentinel",
+			reviews: []gitea.Review{
+				makeReview(42, "bot", "APPROVED", false, "review body\n<!-- review-bot:sonnet -->"),
+			},
+			sentinel: "<!-- review-bot:sonnet -->",
+			wantID:   42,
+		},
+		{
+			name: "wrong sentinel",
+			reviews: []gitea.Review{
+				makeReview(42, "bot", "APPROVED", false, "body\n<!-- review-bot:gpt -->"),
+			},
+			sentinel: "<!-- review-bot:sonnet -->",
+			wantNil:  true,
+		},
+		{
+			name: "multiple reviews, returns first match",
+			reviews: []gitea.Review{
+				makeReview(10, "bot", "APPROVED", false, "old\n<!-- review-bot:gpt -->"),
+				makeReview(20, "bot", "APPROVED", false, "new\n<!-- review-bot:sonnet -->"),
+			},
+			sentinel: "<!-- review-bot:sonnet -->",
+			wantID:   20,
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			got := findOwnReview(tc.reviews, tc.sentinel)
+			if tc.wantNil {
+				if got != nil {
+					t.Errorf("findOwnReview() = %v, want nil", got)
+				}
+			} else {
+				if got == nil {
+					t.Fatal("findOwnReview() = nil, want non-nil")
+				}
+				if got.ID != tc.wantID {
+					t.Errorf("findOwnReview().ID = %d, want %d", got.ID, tc.wantID)
+				}
+			}
+		})
+	}
+}

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/client.go

@@ -57,6 +57,13 @@ type ChangedFile struct {
 	Status   string `json:"status"`
 }
 
+// ReviewComment represents an inline comment to attach to a review.
+type ReviewComment struct {
+	Path        string `json:"path"`
+	NewPosition int64  `json:"new_position"`
+	Body        string `json:"body"`
+}
+
 // GetPullRequest fetches PR metadata.
 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, owner, repo, number)
@@ -129,42 +136,54 @@ func (c *Client) GetFileContentRef(ctx context.Context, owner, repo, filepath, r
 	return string(body), nil
 }
 
-// PostReview submits a review to a PR.
+// PostReview submits a review to a PR and returns the created review.
 // event should be "APPROVED" or "REQUEST_CHANGES".
-func (c *Client) PostReview(ctx context.Context, owner, repo string, number int, event, body string) error {
+// comments are optional inline comments attached to specific lines.
+func (c *Client) PostReview(ctx context.Context, owner, repo string, number int, event, body string, comments []ReviewComment) (*Review, error) {
 	reqURL := fmt.Sprintf("%s/api/v1/repos/%s/%s/pulls/%d/reviews", c.baseURL, owner, repo, number)
 
 	payload := struct {
-		Body  string `json:"body"`
+		Body     string          `json:"body"`
-		Event string `json:"event"`
+		Event    string          `json:"event"`
+		Comments []ReviewComment `json:"comments,omitempty"`
 	}{
-		Body:  body,
+		Body:     body,
-		Event: event,
+		Event:    event,
+		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.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("Content-Type", "application/json")
 
 	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(ctx context.Context, reqURL string) ([]byte, error) {
@@ -266,3 +285,149 @@ func (c *Client) GetAllFilesInPath(ctx context.Context, owner, repo, path 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"`
+}
+
+// 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")
+}
+
+// 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
+}

gitea/client_test.go

@@ -123,15 +123,21 @@ func TestPostReview(t *testing.T) {
 		}
 
 		w.WriteHeader(http.StatusOK)
-		w.Write([]byte(`{}`))
+		w.Write([]byte(`{"id":100,"user":{"login":"review-bot"},"state":"APPROVED","stale":false}`))
 	}))
 	defer server.Close()
 
 	client := NewClient(server.URL, "test-token")
-	err := client.PostReview(context.Background(), "owner", "repo", 3, "APPROVED", "LGTM")
+	review, err := client.PostReview(context.Background(), "owner", "repo", 3, "APPROVED", "LGTM", nil)
 	if err != nil {
 		t.Fatalf("unexpected error: %v", err)
 	}
+	if review.ID != 100 {
+		t.Errorf("expected review ID 100, got %d", review.ID)
+	}
+	if review.User.Login != "review-bot" {
+		t.Errorf("expected user login %q, got %q", "review-bot", review.User.Login)
+	}
 }
 
 func TestGetPullRequest_Non200(t *testing.T) {
@@ -169,7 +175,7 @@ func TestPostReview_Non200(t *testing.T) {
 	defer server.Close()
 
 	client := NewClient(server.URL, "test-token")
-	err := client.PostReview(context.Background(), "owner", "repo", 1, "APPROVED", "test")
+	_, err := client.PostReview(context.Background(), "owner", "repo", 1, "APPROVED", "test", nil)
 	if err == nil {
 		t.Fatal("expected error for 403, got nil")
 	}
@@ -318,3 +324,184 @@ func TestEscapePath(t *testing.T) {
 		})
 	}
 }
+
+func TestListReviews(t *testing.T) {
+	pageCount := 0
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path != "/api/v1/repos/owner/repo/pulls/5/reviews" {
+			t.Errorf("unexpected path: %s", r.URL.Path)
+		}
+		if r.URL.Query().Get("limit") != "50" {
+			t.Errorf("expected limit=50, got %s", r.URL.Query().Get("limit"))
+		}
+		pageCount++
+		w.Header().Set("Content-Type", "application/json")
+		// Return 2 results (less than page size) to signal end
+		w.Write([]byte(`[{"id":10,"user":{"login":"bot-a"},"state":"APPROVED","stale":false},{"id":11,"user":{"login":"bot-b"},"state":"REQUEST_CHANGES","stale":true}]`))
+	}))
+	defer server.Close()
+
+	client := NewClient(server.URL, "test-token")
+	reviews, err := client.ListReviews(context.Background(), "owner", "repo", 5)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if len(reviews) != 2 {
+		t.Fatalf("expected 2 reviews, got %d", len(reviews))
+	}
+	if reviews[0].User.Login != "bot-a" {
+		t.Errorf("expected bot-a, got %s", reviews[0].User.Login)
+	}
+	if pageCount != 1 {
+		t.Errorf("expected 1 page fetch (results < page size), got %d", pageCount)
+	}
+}
+
+func TestListReviews_Pagination(t *testing.T) {
+	pageCount := 0
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		pageCount++
+		page := r.URL.Query().Get("page")
+		w.Header().Set("Content-Type", "application/json")
+		if page == "1" {
+			// Return exactly 50 items to trigger next page fetch
+			items := "["
+			for i := 0; i < 50; i++ {
+				if i > 0 {
+					items += ","
+				}
+				items += fmt.Sprintf(`{"id":%d,"user":{"login":"bot"},"state":"APPROVED","stale":false}`, i+1)
+			}
+			items += "]"
+			w.Write([]byte(items))
+		} else {
+			// Page 2: return fewer than 50 to signal end
+			w.Write([]byte(`[{"id":51,"user":{"login":"bot"},"state":"APPROVED","stale":false}]`))
+		}
+	}))
+	defer server.Close()
+
+	client := NewClient(server.URL, "test-token")
+	reviews, err := client.ListReviews(context.Background(), "owner", "repo", 5)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if len(reviews) != 51 {
+		t.Fatalf("expected 51 reviews across 2 pages, got %d", len(reviews))
+	}
+	if pageCount != 2 {
+		t.Errorf("expected 2 page fetches, got %d", pageCount)
+	}
+}
+
+func TestDeleteReview(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path != "/api/v1/repos/owner/repo/pulls/5/reviews/10" {
+			t.Errorf("unexpected path: %s", r.URL.Path)
+		}
+		if r.Method != "DELETE" {
+			t.Errorf("expected DELETE, got %s", r.Method)
+		}
+		w.WriteHeader(http.StatusNoContent)
+	}))
+	defer server.Close()
+
+	client := NewClient(server.URL, "test-token")
+	err := client.DeleteReview(context.Background(), "owner", "repo", 5, 10)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+}
+
+func TestDeleteReview_Forbidden(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusForbidden)
+		w.Write([]byte(`{"message":"forbidden"}`))
+	}))
+	defer server.Close()
+
+	client := NewClient(server.URL, "test-token")
+	err := client.DeleteReview(context.Background(), "owner", "repo", 5, 10)
+	if err == nil {
+		t.Fatal("expected error for 403, got nil")
+	}
+}
+
+func TestEditComment(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.Method != http.MethodPatch {
+			t.Errorf("expected PATCH, got %s", r.Method)
+		}
+		if r.URL.Path != "/api/v1/repos/owner/repo/issues/comments/42" {
+			t.Errorf("unexpected path: %s", r.URL.Path)
+		}
+
+		var payload struct {
+			Body string `json:"body"`
+		}
+		json.NewDecoder(r.Body).Decode(&payload)
+		if payload.Body != "updated body" {
+			t.Errorf("unexpected body: %s", payload.Body)
+		}
+
+		w.WriteHeader(http.StatusOK)
+		w.Write([]byte(`{"id": 42, "body": "updated body"}`))
+	}))
+	defer server.Close()
+
+	client := NewClient(server.URL, "test-token")
+	err := client.EditComment(context.Background(), "owner", "repo", 42, "updated body")
+	if err != nil {
+		t.Fatalf("EditComment() error = %v", err)
+	}
+}
+
+func TestEditComment_Forbidden(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusForbidden)
+		w.Write([]byte(`{"message": "not allowed"}`))
+	}))
+	defer server.Close()
+
+	client := NewClient(server.URL, "test-token")
+	err := client.EditComment(context.Background(), "owner", "repo", 42, "new body")
+	if err == nil {
+		t.Fatal("expected error for 403 response")
+	}
+}
+
+func TestGetTimelineReviewCommentID(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path != "/api/v1/repos/owner/repo/issues/5/timeline" {
+			t.Errorf("unexpected path: %s", r.URL.Path)
+		}
+		w.Write([]byte(`[
+			{"id": 100, "type": "comment", "body": "random"},
+			{"id": 200, "type": "review", "body": "other review <!-- review-bot:gpt -->"},
+			{"id": 300, "type": "review", "body": "our review <!-- review-bot:sonnet -->"}
+		]`))
+	}))
+	defer server.Close()
+
+	client := NewClient(server.URL, "test-token")
+	id, err := client.GetTimelineReviewCommentID(context.Background(), "owner", "repo", 5, "<!-- review-bot:sonnet -->")
+	if err != nil {
+		t.Fatalf("GetTimelineReviewCommentID() error = %v", err)
+	}
+	if id != 300 {
+		t.Errorf("got id=%d, want 300", id)
+	}
+}
+
+func TestGetTimelineReviewCommentID_NotFound(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Write([]byte(`[{"id": 100, "type": "review", "body": "no match"}]`))
+	}))
+	defer server.Close()
+
+	client := NewClient(server.URL, "test-token")
+	_, err := client.GetTimelineReviewCommentID(context.Background(), "owner", "repo", 5, "<!-- review-bot:sonnet -->")
+	if err == nil {
+		t.Fatal("expected error when sentinel not found")
+	}
+}

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/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")
+		}
+	}
+}

llm/client.go

@@ -1,4 +1,6 @@
-// Package llm provides a client for OpenAI-compatible chat completion APIs.
+// Package llm provides clients for LLM chat completion APIs.
+//
+// Supports OpenAI-compatible (default) and Anthropic Messages API providers.
 package llm
 
 import (
@@ -12,24 +14,37 @@ import (
 	"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"
+)
+
+// Client calls an LLM chat completion API.
 // A Client is safe for concurrent use by multiple goroutines after construction.
-// WithTimeout and WithTemperature must be called during setup, before concurrent use.
+// WithTimeout, WithTemperature, and WithProvider must be called during setup,
+// before concurrent use.
 type Client struct {
 	baseURL     string
 	apiKey      string
 	model       string
 	temperature float64
+	provider    Provider
 	http        *http.Client
 }
 
-// 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, "/"),
+		baseURL:  strings.TrimRight(baseURL, "/"),
-		apiKey:  apiKey,
+		apiKey:   apiKey,
-		model:   model,
+		model:    model,
-		http:    &http.Client{Timeout: 5 * time.Minute},
+		provider: ProviderOpenAI,
+		http:     &http.Client{Timeout: 5 * time.Minute},
 	}
 }
 
@@ -45,20 +60,39 @@ func (c *Client) WithTemperature(t float64) *Client {
 	return c
 }
 
+// WithProvider sets the API provider format (openai or anthropic).
+func (c *Client) WithProvider(p Provider) *Client {
+	c.provider = p
+	return c
+}
+
 // Message represents a chat message.
 type Message struct {
 	Role    string `json:"role"`
 	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) {
+	switch c.provider {
+	case ProviderAnthropic:
+		return c.completeAnthropic(ctx, messages)
+	default:
+		return c.completeOpenAI(ctx, messages)
+	}
+}
+
+// --- 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 {
@@ -67,8 +101,7 @@ type ChatResponse struct {
 	} `json:"choices"`
 }
 
-// Complete sends a chat completion request and returns the assistant's response content.
+func (c *Client) completeOpenAI(ctx context.Context, messages []Message) (string, error) {
-func (c *Client) Complete(ctx context.Context, messages []Message) (string, error) {
 	reqBody := ChatRequest{
 		Model:       c.model,
 		Temperature: c.temperature,
@@ -81,37 +114,126 @@ func (c *Client) Complete(ctx context.Context, messages []Message) (string, erro
 	}
 
 	url := c.baseURL + "/chat/completions"
-	req, err := http.NewRequestWithContext(ctx, "POST", url, bytes.NewReader(data))
+	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("Content-Type", "application/json")
 
+	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 {
+	Model       string            `json:"model"`
+	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 resp.StatusCode < 200 || resp.StatusCode >= 300 {
-	if err := json.Unmarshal(body, &chatResp); err != nil {
+		return "", fmt.Errorf("LLM API error (status %d): %s", resp.StatusCode, string(body))
-		return "", fmt.Errorf("parse response: %w", err)
 	}
 
-	if len(chatResp.Choices) == 0 {
+	return parse(body)
-		return "", fmt.Errorf("no choices in LLM response")
-	}
-
-	return chatResp.Choices[0].Message.Content, nil
 }

llm/client_test.go

@@ -208,3 +208,90 @@ func TestWithTimeout(t *testing.T) {
 		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)
+	}
+}

review/formatter.go

@@ -9,6 +9,11 @@ import (
 func FormatMarkdown(result *ReviewResult, reviewerName string) string {
 	var sb strings.Builder
 
+	if reviewerName != "" {
+		title := strings.ToUpper(reviewerName[:1]) + reviewerName[1:]
+		sb.WriteString(fmt.Sprintf("# %s Review\n\n", title))
+	}
+
 	sb.WriteString("## Summary\n\n")
 	sb.WriteString(result.Summary)
 	sb.WriteString("\n\n")
@@ -30,6 +35,8 @@ func FormatMarkdown(result *ReviewResult, reviewerName string) string {
 
 	if reviewerName != "" {
 		sb.WriteString(fmt.Sprintf("\n---\n*Review by %s*\n", reviewerName))
+		// Hidden sentinel for identifying this bot's reviews during cleanup
+		sb.WriteString(fmt.Sprintf("\n<!-- review-bot:%s -->\n", reviewerName))
 	}
 
 	return sb.String()

review/formatter_test.go

@@ -116,3 +116,46 @@ func TestGiteaEvent(t *testing.T) {
 		}
 	}
 }
+
+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")
+	}
+
+	// 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")
+	}
+}