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

@@ -622,21 +622,28 @@ 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
-	if !strings.HasPrefix(fullPath, absWorkspace+string(filepath.Separator)) && fullPath != absWorkspace {
+
+	// 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)
 	}
-	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"
-	"strings"
 	"path/filepath"
+	"strings"
 	"testing"
 
 	"gitea.weiker.me/rodin/review-bot/gitea"

docs/DESIGN-51-personas.md

@@ -318,36 +318,13 @@ 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: JSON Instead of YAML
+## Design Revision: YAML with gopkg.in/yaml.v3
 
-**Reason:** Project convention is "Go standard library only — no external dependencies."
+**Decision:** Add `gopkg.in/yaml.v3` as a dependency.
 
-YAML requires `gopkg.in/yaml.v3` or similar. To maintain zero dependencies, persona files will use JSON instead.
+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
 
-### 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`.
+The implementation supports both YAML (`.yaml`, `.yml`) and JSON (`.json`) for backwards compatibility, with YAML as the default for built-in personas.

review/formatter.go

@@ -7,39 +7,7 @@ import (
 
 // FormatMarkdown formats a ReviewResult into the markdown body for a Gitea review.
 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")
-
-	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()
+	return FormatMarkdownWithDisplay(result, reviewerName, reviewerName)
 }
 
 // GiteaEvent converts the verdict to the Gitea API event string.
@@ -55,6 +23,8 @@ 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(filepath.Join("personas", filename))
+	data, err := embeddedPersonas.ReadFile("personas/" + filename) // embed.FS paths use forward slashes per io/fs spec
 	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 (same as base, but with persona context)
+	// 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")
@@ -61,24 +61,10 @@ 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("{\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("- Only report findings within your focus areas. Ignore everything else.\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")
 

review/prompt.go

@@ -7,6 +7,28 @@ 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.
@@ -23,24 +45,10 @@ 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("{\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")