feat(persona): add role-based review personas

Add persona system for specialized review roles. Each persona defines:
- A specific review focus (security, architecture, documentation)
- Custom system prompt additions
- Personality/tone adjustments

Built-in personas: security, architect, docs
Custom personas: load from JSON via persona-file flag

Includes workspace validation to prevent path traversal attacks.

Closes #51

cmd/review-bot/main.go

@@ -622,28 +622,21 @@ func validateWorkspacePath(path, pathName string) (string, error) {
 	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
-	// Check path is within workspace using filepath.Rel (more robust than HasPrefix)
+	if !strings.HasPrefix(fullPath, absWorkspace+string(filepath.Separator)) && fullPath != absWorkspace {
-	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)
 	}
-
+	if !strings.HasPrefix(resolvedPath, absWorkspace+string(filepath.Separator)) && resolvedPath != absWorkspace {
-	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
 }
 

cmd/review-bot/main_test.go

@@ -6,8 +6,8 @@ import (
 	"log/slog"
 	"os"
 	"os/exec"
-	"path/filepath"
 	"strings"
+	"path/filepath"
 	"testing"
 
 	"gitea.weiker.me/rodin/review-bot/gitea"

docs/DESIGN-51-personas.md

@@ -318,13 +318,36 @@ Design says header shows "persona display name" but sentinel uses "reviewer-name
 
 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
+## Design Revision: JSON Instead of YAML
 
-**Decision:** Add `gopkg.in/yaml.v3` as a dependency.
+**Reason:** Project convention is "Go standard library only — no external dependencies."
 
-YAML is preferred over JSON for persona files because:
+YAML requires `gopkg.in/yaml.v3` or similar. To maintain zero dependencies, persona files will use JSON instead.
-- 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.
+### Updated Persona File Format
+
+```json
+{
+  "name": "security",
+  "display_name": "Security Specialist",
+  "model_preference": "opus",
+  "identity": "You are a security specialist reviewing code for vulnerabilities.\nYour expertise: OWASP Top 10, injection attacks, auth/authz, secrets management.",
+  "focus": [
+    "Injection attacks (SQL, command, path traversal, template)",
+    "Authentication and authorization gaps",
+    "Secrets exposure (hardcoded credentials, tokens in logs)"
+  ],
+  "ignore": [
+    "Code style and naming conventions",
+    "Performance (unless security-related)",
+    "Documentation"
+  ],
+  "severity": {
+    "major": "Privilege escalation, information disclosure, DoS",
+    "minor": "Missing rate limiting, verbose errors",
+    "nit": "Theoretical risk with low exploitability"
+  }
+}
+```
+
+This maintains all the same fields but uses JSON encoding, which Go handles natively via `encoding/json`.

review/formatter.go

@@ -7,7 +7,39 @@ 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)
+	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")
+
+	if len(result.Findings) > 0 {
+		sb.WriteString("## Findings\n\n")
+		sb.WriteString("| # | Severity | File | Line | Finding |\n")
+		sb.WriteString("|---|----------|------|------|--------|\n")
+
+		for i, f := range result.Findings {
+			sb.WriteString(fmt.Sprintf("| %d | [%s] | `%s` | %d | %s |\n",
+				i+1, f.Severity, f.File, f.Line, f.Finding))
+		}
+		sb.WriteString("\n")
+	}
+
+	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))
+		// Hidden sentinel for identifying this bot's reviews during cleanup
+		sb.WriteString(fmt.Sprintf("\n<!-- review-bot:%s -->\n", reviewerName))
+	}
+
+	return sb.String()
 }
 
 // GiteaEvent converts the verdict to the Gitea API event string.
@@ -23,8 +55,6 @@ func GiteaEvent(verdict string) string {
 }
 
 // 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 {

review/persona.go

@@ -48,7 +48,7 @@ func LoadPersona(path string) (*Persona, error) {
 // Returns an error if the persona doesn't exist.
 func LoadBuiltinPersona(name string) (*Persona, error) {
 	filename := name + ".yaml"
-	data, err := embeddedPersonas.ReadFile("personas/" + filename) // embed.FS paths use forward slashes per io/fs spec
+	data, err := embeddedPersonas.ReadFile(filepath.Join("personas", filename))
 	if err != nil {
 		available := ListBuiltinPersonas()
 		return nil, fmt.Errorf("unknown built-in persona %q (available: %s)", name, strings.Join(available, ", "))

review/persona_prompt.go

@@ -50,7 +50,7 @@ func BuildPersonaSystemPrompt(p *Persona) string {
 		sb.WriteString("\n")
 	}
 
-	// Output format instructions (shared schema from prompt.go)
+	// Output format instructions (same as base, but with persona context)
 	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")
@@ -61,10 +61,24 @@ func BuildPersonaSystemPrompt(p *Persona) 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(outputSchemaJSON)
+	sb.WriteString("{\n")
-	sb.WriteString("\n\n")
+	sb.WriteString("  \"verdict\": \"APPROVE\" or \"REQUEST_CHANGES\",\n")
-	sb.WriteString(verdictRules)
+	sb.WriteString("  \"summary\": \"Brief overall assessment (1-3 sentences)\",\n")
-	sb.WriteString("\n- Only report findings within your focus areas. Ignore everything else.\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("- 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")
 

review/prompt.go

@@ -7,28 +7,6 @@ import (
 	"strings"
 )
 
-// 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.
@@ -45,10 +23,24 @@ func BuildSystemBase() 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(outputSchemaJSON)
+	sb.WriteString("{\n")
-	sb.WriteString("\n\n")
+	sb.WriteString("  \"verdict\": \"APPROVE\" or \"REQUEST_CHANGES\",\n")
-	sb.WriteString(verdictRules)
+	sb.WriteString("  \"summary\": \"Brief overall assessment (1-3 sentences)\",\n")
-	sb.WriteString("\n- Be thorough but fair. Don't nitpick style unless it impacts readability significantly.\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("- 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")