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

.gitea/actions/review/action.yml

@@ -79,7 +79,7 @@ inputs:
     required: false
     default: ''
   persona-file:
-    description: 'Path to custom persona JSON file'
+    description: 'Path to persona JSON file with custom review focus'
     required: false
     default: ''
 

README.md

@@ -380,32 +380,38 @@ Each persona posts independently with its own sentinel, so reviews don't interfe
 
 ### Custom Personas
 
-Create a JSON file with your domain-specific review focus:
+Create a YAML file with your domain-specific review focus:
 
-```json
-// .review/personas/trading.json
-{
-  "name": "trading",
-  "display_name": "Trading Domain Expert",
-  "identity": "You are a trading systems expert reviewing code for correctness.\n\nYour expertise:\n- Order lifecycle and state machines\n- Fill handling and partial fills\n- Position tracking and P&L calculations\n- Event sourcing invariants",
-  "focus": [
-    "Order state machine correctness",
-    "Fill handling edge cases (partial, overfill)",
-    "Position and P&L calculation accuracy",
-    "Event replay determinism",
-    "Decimal precision for money"
-  ],
-  "ignore": [
-    "Code style",
-    "General performance",
-    "Documentation formatting"
-  ],
-  "severity": {
-    "major": "Bugs that cause incorrect positions, fills, or money calculations",
-    "minor": "Edge cases that could cause issues under unusual conditions",
-    "nit": "Clarity improvements for domain logic"
-  }
-}
+```yaml
+# .review/personas/trading.yaml
+name: trading
+display_name: Trading Domain Expert
+
+identity: |
+  You are a trading systems expert reviewing code for correctness.
+  
+  Your expertise:
+  - Order lifecycle and state machines
+  - Fill handling and partial fills
+  - Position tracking and P&L calculations
+  - Event sourcing invariants
+
+focus:
+  - Order state machine correctness
+  - Fill handling edge cases (partial, overfill)
+  - Position and P&L calculation accuracy
+  - Event replay determinism
+  - Decimal precision for money
+
+ignore:
+  - Code style
+  - General performance
+  - Documentation formatting
+
+severity:
+  major: Bugs that cause incorrect positions, fills, or money calculations
+  minor: Edge cases that could cause issues under unusual conditions
+  nit: Clarity improvements for domain logic
 ```
 
 Use it in CI:
@@ -414,17 +420,18 @@ Use it in CI:
 - uses: rodin/review-bot/.gitea/actions/review@v1
   with:
     reviewer-name: trading
-    persona-file: .review/personas/trading.json
+    persona-file: .review/personas/trading.yaml
     ...
 ```
 
+JSON format is also supported for backwards compatibility.
 
 ### Persona vs system-prompt-file
 
 | Feature | `persona` / `persona-file` | `system-prompt-file` |
 |---------|---------------------------|----------------------|
 | Replaces base prompt | Yes | No (appends) |
-| Structured format | Yes (JSON) | No (freeform) |
+| Structured format | Yes (YAML/JSON) | No (freeform) |
 | Focus/ignore lists | Yes | Manual |
 | Severity calibration | Yes | Manual |
 | Header display name | Yes | No |

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 using filepath.Rel (more robust than HasPrefix)
-	rel, err := filepath.Rel(absWorkspace, fullPath)
-	if err != nil || strings.HasPrefix(rel, "..") {
+	// Check path is within workspace
+	if !strings.HasPrefix(fullPath, absWorkspace+string(filepath.Separator)) && fullPath != absWorkspace {
 		return "", fmt.Errorf("%s resolves outside workspace: path=%s workspace=%s", pathName, fullPath, absWorkspace)
 	}
-
 	// Resolve symlinks and re-validate to prevent symlink traversal
 	resolvedPath, err := filepath.EvalSymlinks(fullPath)
 	if err != nil {
 		return "", fmt.Errorf("failed to resolve %s: %w", pathName, err)
 	}
-
-	relResolved, err := filepath.Rel(absWorkspace, resolvedPath)
-	if err != nil || strings.HasPrefix(relResolved, "..") {
+	if !strings.HasPrefix(resolvedPath, absWorkspace+string(filepath.Separator)) && resolvedPath != absWorkspace {
 		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"
@@ -103,13 +103,11 @@ func TestValidateWorkspacePath(t *testing.T) {
 			errMatch:  "resolves outside workspace",
 		},
 		{
-			name:      "absolute path normalized to workspace-relative",
+			name:      "absolute path gets normalized to relative",
 			workspace: tmpDir,
 			path:      "/etc/passwd",
 			wantErr:   true,
-			// Go 1.21+ filepath.Join normalizes absolute paths: Join("/tmp/x", "/etc/passwd")
-			// becomes "/tmp/x/etc/passwd", which is within workspace but doesn't exist.
-			errMatch: "failed to resolve",
+			errMatch:  "failed to resolve", // filepath.Join strips leading / making it <workspace>/etc/passwd which doesn't exist
 		},
 		{
 			name:      "nonexistent file",
@@ -154,6 +152,7 @@ func TestValidateWorkspacePath(t *testing.T) {
 	}
 }
 
+
 func makeReview(id int64, login, state string, stale bool, body string) gitea.Review {
 	r := gitea.Review{
 		ID:    id,
@@ -165,6 +164,7 @@ func makeReview(id int64, login, state string, stale bool, body string) gitea.Re
 	return r
 }
 
+
 func TestBuildSupersededBody(t *testing.T) {
 	original := "# Review\n\nLooks good.\n\n<!-- review-bot:sonnet -->"
 	sentinel := "<!-- review-bot:sonnet -->"
@@ -734,8 +734,8 @@ func TestExtractSentinelName_EdgeCases(t *testing.T) {
 		{"<!-- review-bot:sonnet --> rest", "sonnet"},
 		{"<!-- review-bot:gpt-review --> rest", "gpt-review"},
 		{"no sentinel here", "unknown"},
-		{"<!-- review-bot:", "unknown"},                   // prefix but no suffix
-		{"prefix <!-- review-bot:abc --> end", "abc"},     // embedded in text
+		{"<!-- review-bot:", "unknown"},       // prefix but no suffix
+		{"prefix <!-- review-bot:abc --> end", "abc"}, // embedded in text
 	}
 
 	for _, tc := range tests {

docs/DESIGN-51-personas.md

@@ -1,9 +1,5 @@
 # Design: Role-based Review Personas (Issue #51)
 
-> **Note:** This design was revised during implementation to use JSON instead of YAML
-> to maintain the repository's zero-external-dependencies convention. All persona
-> files use JSON format. See "Design Revision" section at the end for details.
-
 ## Problem
 
 Current review-bot performs generic code review. Every reviewer (regardless of `reviewer-name`) uses the same base prompt and evaluates the same concerns. This leads to:
@@ -31,14 +27,14 @@ A persona is a named review role with:
 - **Scope boundaries** — What do I explicitly NOT comment on?
 - **Severity calibration** — What counts as MAJOR/MINOR/NIT for MY domain?
 
-Personas are defined in JSON files that can live:
+Personas are defined in YAML files that can live:
 1. In the pattern repos (shared across projects)
 2. In the target repo (project-specific personas)
-3. Inline via a new `--persona-file` flag (JSON format)
+3. Inline via a new `--persona-file` flag
 
 ### 2. Persona File Format
 
-```json
+```yaml
 # .review/personas/security.yaml
 name: security
 display_name: Security Specialist
@@ -81,7 +77,7 @@ output_format: |
 ### 3. New CLI Flags
 
 ```
---persona-file PATH      Path to persona JSON file (local or in repo)
+--persona-file PATH      Path to persona YAML file (local or in repo)
 --persona NAME           Built-in persona name (security, architect, domain)
 ```
 
@@ -322,13 +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:
-- Multi-line strings are cleaner (no escaping quotes in identity/focus text)
-- Comments are supported for documentation
-- More human-readable for complex persona definitions
+YAML requires `gopkg.in/yaml.v3` or similar. To maintain zero dependencies, persona files will use JSON instead.
 
-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`.

go.mod

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

go.sum

@@ -0,0 +1,3 @@
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

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 {
@@ -37,7 +67,7 @@ func FormatMarkdownWithDisplay(result *ReviewResult, displayName, sentinelName s
 	}
 
 	if headerName != "" {
-		title := CapitalizeFirst(headerName)
+		title := strings.ToUpper(headerName[:1]) + headerName[1:]
 		sb.WriteString(fmt.Sprintf("# %s Review\n\n", title))
 	}
 

review/persona.go

@@ -5,34 +5,37 @@ import (
 	"encoding/json"
 	"fmt"
 	"os"
+	"path/filepath"
 	"strings"
-	"unicode/utf8"
+
+	"gopkg.in/yaml.v3"
 )
 
-//go:embed personas/*.json
+//go:embed personas/*.yaml
 var embeddedPersonas embed.FS
 
 // Persona defines a specialized review role with focused expertise.
 type Persona struct {
-	Name         string   `json:"name"`
-	DisplayName  string   `json:"display_name"`
-	ModelPref    string   `json:"model_preference,omitempty"`
-	Identity     string   `json:"identity"`
-	Focus        []string `json:"focus"`
-	Ignore       []string `json:"ignore"`
-	Severity     Severity `json:"severity"`
-	OutputFormat string   `json:"output_format,omitempty"`
+	Name         string   `json:"name" yaml:"name"`
+	DisplayName  string   `json:"display_name" yaml:"display_name"`
+	ModelPref    string   `json:"model_preference,omitempty" yaml:"model_preference,omitempty"`
+	Identity     string   `json:"identity" yaml:"identity"`
+	Focus        []string `json:"focus" yaml:"focus"`
+	Ignore       []string `json:"ignore" yaml:"ignore"`
+	Severity     Severity `json:"severity" yaml:"severity"`
+	OutputFormat string   `json:"output_format,omitempty" yaml:"output_format,omitempty"`
 }
 
 // Severity defines what constitutes each severity level for this persona.
 // These are prompt guidance for the LLM, not output format changes.
 type Severity struct {
-	Major string `json:"major"`
-	Minor string `json:"minor"`
-	Nit   string `json:"nit"`
+	Major string `json:"major" yaml:"major"`
+	Minor string `json:"minor" yaml:"minor"`
+	Nit   string `json:"nit" yaml:"nit"`
 }
 
-// LoadPersona loads a persona from a JSON file path.
+// LoadPersona loads a persona from a file path.
+// Supports both YAML (.yaml, .yml) and JSON (.json) formats.
 func LoadPersona(path string) (*Persona, error) {
 	data, err := os.ReadFile(path)
 	if err != nil {
@@ -44,8 +47,8 @@ func LoadPersona(path string) (*Persona, error) {
 // LoadBuiltinPersona loads a built-in persona by name.
 // Returns an error if the persona doesn't exist.
 func LoadBuiltinPersona(name string) (*Persona, error) {
-	filename := name + ".json"
-	data, err := embeddedPersonas.ReadFile("personas/" + filename) // embed.FS paths use forward slashes per io/fs spec
+	filename := name + ".yaml"
+	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, ", "))
@@ -54,11 +57,10 @@ func LoadBuiltinPersona(name string) (*Persona, error) {
 }
 
 // ListBuiltinPersonas returns the names of all built-in personas.
-// Returns an empty slice if the embedded directory cannot be read.
 func ListBuiltinPersonas() []string {
 	entries, err := embeddedPersonas.ReadDir("personas")
 	if err != nil {
-		return []string{}
+		return nil
 	}
 	var names []string
 	for _, e := range entries {
@@ -66,8 +68,10 @@ func ListBuiltinPersonas() []string {
 			continue
 		}
 		name := e.Name()
-		if strings.HasSuffix(name, ".json") {
-			names = append(names, strings.TrimSuffix(name, ".json"))
+		if strings.HasSuffix(name, ".yaml") {
+			names = append(names, strings.TrimSuffix(name, ".yaml"))
+		} else if strings.HasSuffix(name, ".yml") {
+			names = append(names, strings.TrimSuffix(name, ".yml"))
 		}
 	}
 	return names
@@ -75,9 +79,20 @@ func ListBuiltinPersonas() []string {
 
 func parsePersona(data []byte, source string) (*Persona, error) {
 	var p Persona
-	if err := json.Unmarshal(data, &p); err != nil {
-		return nil, fmt.Errorf("parse persona %s: %w", source, err)
+	
+	// Determine format by extension or try YAML first (it's a superset of JSON)
+	ext := strings.ToLower(filepath.Ext(source))
+	if ext == ".json" {
+		if err := json.Unmarshal(data, &p); err != nil {
+			return nil, fmt.Errorf("parse persona %s: %w", source, err)
+		}
+	} else {
+		// YAML (also handles .yaml, .yml, and builtin: prefix)
+		if err := yaml.Unmarshal(data, &p); err != nil {
+			return nil, fmt.Errorf("parse persona %s: %w", source, err)
+		}
 	}
+	
 	if err := validatePersona(&p, source); err != nil {
 		return nil, err
 	}
@@ -97,16 +112,3 @@ func validatePersona(p *Persona, source string) error {
 	}
 	return nil
 }
-
-// CapitalizeFirst capitalizes the first rune of a string in a Unicode-safe way.
-// Returns the original string if it's empty.
-func CapitalizeFirst(s string) string {
-	if s == "" {
-		return s
-	}
-	r, size := utf8.DecodeRuneInString(s)
-	if r == utf8.RuneError {
-		return s
-	}
-	return strings.ToUpper(string(r)) + s[size:]
-}

review/persona_prompt.go

@@ -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\n")
-	sb.WriteString(verdictRules)
-	sb.WriteString("\n- Only report findings within your focus areas. Ignore everything else.\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("- 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/persona_test.go

@@ -87,22 +87,26 @@ func TestListBuiltinPersonas(t *testing.T) {
 	}
 }
 
-func TestLoadPersonaFromJSONFile(t *testing.T) {
+func TestLoadPersonaFromYAMLFile(t *testing.T) {
 	dir := t.TempDir()
-	path := filepath.Join(dir, "test.json")
+	path := filepath.Join(dir, "test.yaml")
 
-	content := `{
-		"name": "test",
-		"display_name": "Test Persona",
-		"identity": "You are a test persona.\nMulti-line identity works.",
-		"focus": ["testing", "validation"],
-		"ignore": ["nothing"],
-		"severity": {
-			"major": "Big problems",
-			"minor": "Small problems",
-			"nit": "Tiny problems"
-		}
-	}`
+	content := `
+name: test
+display_name: Test Persona
+identity: |
+  You are a test persona.
+  Multi-line identity works.
+focus:
+  - testing
+  - validation
+ignore:
+  - nothing
+severity:
+  major: Big problems
+  minor: Small problems
+  nit: Tiny problems
+`
 
 	if err := os.WriteFile(path, []byte(content), 0644); err != nil {
 		t.Fatalf("failed to write test file: %v", err)
@@ -127,25 +131,59 @@ func TestLoadPersonaFromJSONFile(t *testing.T) {
 	}
 }
 
+func TestLoadPersonaFromJSONFile(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "test.json")
+
+	content := `{
+		"name": "test",
+		"display_name": "Test Persona",
+		"identity": "You are a test persona.",
+		"focus": ["testing"],
+		"ignore": ["nothing"],
+		"severity": {
+			"major": "Big problems",
+			"minor": "Small problems",
+			"nit": "Tiny problems"
+		}
+	}`
+
+	if err := os.WriteFile(path, []byte(content), 0644); err != nil {
+		t.Fatalf("failed to write test file: %v", err)
+	}
+
+	p, err := LoadPersona(path)
+	if err != nil {
+		t.Fatalf("LoadPersona failed: %v", err)
+	}
+
+	if p.Name != "test" {
+		t.Errorf("Name = %q, want %q", p.Name, "test")
+	}
+	if p.DisplayName != "Test Persona" {
+		t.Errorf("DisplayName = %q, want %q", p.DisplayName, "Test Persona")
+	}
+}
+
 func TestLoadPersonaValidation(t *testing.T) {
 	tests := []struct {
 		name    string
-		json    string
+		yaml    string
 		wantErr string
 	}{
 		{
 			name:    "missing name",
-			json:    `{"identity": "test"}`,
+			yaml:    "identity: test",
 			wantErr: "name is required",
 		},
 		{
 			name:    "missing identity",
-			json:    `{"name": "test"}`,
+			yaml:    "name: test",
 			wantErr: "identity is required",
 		},
 		{
 			name: "display_name defaults to name",
-			json: `{"name": "test", "identity": "test identity"}`,
+			yaml: "name: test\nidentity: test identity",
 			// No error expected - should succeed
 		},
 	}
@@ -153,8 +191,8 @@ func TestLoadPersonaValidation(t *testing.T) {
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			dir := t.TempDir()
-			path := filepath.Join(dir, "test.json")
-			if err := os.WriteFile(path, []byte(tt.json), 0644); err != nil {
+			path := filepath.Join(dir, "test.yaml")
+			if err := os.WriteFile(path, []byte(tt.yaml), 0644); err != nil {
 				t.Fatalf("failed to write test file: %v", err)
 			}
 
@@ -184,56 +222,21 @@ func TestLoadPersonaValidation(t *testing.T) {
 }
 
 func TestLoadPersonaFileNotFound(t *testing.T) {
-	_, err := LoadPersona("/nonexistent/path/persona.json")
+	_, err := LoadPersona("/nonexistent/path/persona.yaml")
 	if err == nil {
 		t.Error("expected error for nonexistent file")
 	}
 }
 
-func TestLoadPersonaInvalidJSON(t *testing.T) {
+func TestLoadPersonaInvalidYAML(t *testing.T) {
 	dir := t.TempDir()
-	path := filepath.Join(dir, "invalid.json")
-	if err := os.WriteFile(path, []byte("not valid json {"), 0644); err != nil {
+	path := filepath.Join(dir, "invalid.yaml")
+	if err := os.WriteFile(path, []byte("not: valid: yaml: here"), 0644); err != nil {
 		t.Fatalf("failed to write test file: %v", err)
 	}
 
 	_, err := LoadPersona(path)
 	if err == nil {
-		t.Error("expected error for invalid JSON")
-	}
-}
-
-func TestCapitalizeFirst(t *testing.T) {
-	tests := []struct {
-		input string
-		want  string
-	}{
-		{"hello", "Hello"},
-		{"Hello", "Hello"},
-		{"HELLO", "HELLO"},
-		{"a", "A"},
-		{"", ""},
-		{"日本語", "日本語"}, // Non-ASCII: Japanese doesn't have case
-		{"über", "Über"},   // German umlaut
-		{"élève", "Élève"}, // French accent
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.input, func(t *testing.T) {
-			got := CapitalizeFirst(tt.input)
-			if got != tt.want {
-				t.Errorf("CapitalizeFirst(%q) = %q, want %q", tt.input, got, tt.want)
-			}
-		})
-	}
-}
-
-func TestListBuiltinPersonasReturnsEmptySlice(t *testing.T) {
-	// ListBuiltinPersonas should return an empty slice (not nil) on error.
-	// We can't easily test the error case, but we can verify the success case
-	// returns a proper slice.
-	names := ListBuiltinPersonas()
-	if names == nil {
-		t.Error("ListBuiltinPersonas should return empty slice, not nil")
+		t.Error("expected error for invalid YAML")
 	}
 }

review/personas/architect.json

@@ -1,26 +0,0 @@
-{
-  "name": "architect",
-  "display_name": "Software Architect",
-  "identity": "You are a software architect reviewing code for design quality.\n\nYour expertise:\n- Design patterns and anti-patterns\n- Code organization and module boundaries\n- API design and contracts\n- Testability and dependency injection\n- Consistency with existing architecture\n- Technical debt identification",
-  "focus": [
-    "Design pattern violations or misuse",
-    "Module boundary violations (inappropriate coupling)",
-    "API design issues (unclear contracts, leaky abstractions)",
-    "Testability problems (hidden dependencies, god objects)",
-    "Inconsistency with existing codebase patterns",
-    "Unnecessary complexity or over-engineering",
-    "Missing abstractions or premature abstraction"
-  ],
-  "ignore": [
-    "Security vulnerabilities (security persona handles these)",
-    "Performance micro-optimizations",
-    "Code style and formatting",
-    "Documentation typos",
-    "Test implementation details"
-  ],
-  "severity": {
-    "major": "Architectural violations that will cause maintenance problems or make the codebase harder to evolve",
-    "minor": "Design issues that reduce clarity or testability but don't block progress",
-    "nit": "Minor pattern deviations or style preferences"
-  }
-}

review/personas/architect.yaml

@@ -0,0 +1,34 @@
+name: architect
+display_name: Software Architect
+
+identity: |
+  You are a software architect reviewing code for design quality.
+  
+  Your expertise:
+  - Design patterns and anti-patterns
+  - Code organization and module boundaries
+  - API design and contracts
+  - Testability and dependency injection
+  - Consistency with existing architecture
+  - Technical debt identification
+
+focus:
+  - Design pattern violations or misuse
+  - Module boundary violations (inappropriate coupling)
+  - API design issues (unclear contracts, leaky abstractions)
+  - Testability problems (hidden dependencies, god objects)
+  - Inconsistency with existing codebase patterns
+  - Unnecessary complexity or over-engineering
+  - Missing abstractions or premature abstraction
+
+ignore:
+  - Security vulnerabilities (security persona handles these)
+  - Performance micro-optimizations
+  - Code style and formatting
+  - Documentation typos
+  - Test implementation details
+
+severity:
+  major: "Architectural violations that will cause maintenance problems or make the codebase harder to evolve"
+  minor: "Design issues that reduce clarity or testability but don't block progress"
+  nit: "Minor pattern deviations or style preferences"

review/personas/docs.json

@@ -1,26 +0,0 @@
-{
-  "name": "docs",
-  "display_name": "Documentation Reviewer",
-  "identity": "You are a documentation specialist reviewing code for clarity and documentation quality.\n\nYour expertise:\n- API documentation and examples\n- Code comments and their accuracy\n- Error message clarity\n- README and guide quality\n- Naming clarity and self-documenting code",
-  "focus": [
-    "Missing or outdated documentation",
-    "Unclear or misleading comments",
-    "Poor error messages (cryptic, unhelpful, missing context)",
-    "Confusing naming (functions, variables, types)",
-    "Missing examples for complex APIs",
-    "Inconsistent terminology",
-    "Documentation that contradicts the code"
-  ],
-  "ignore": [
-    "Security vulnerabilities",
-    "Performance issues",
-    "Design patterns",
-    "Test coverage",
-    "Code style (unless it affects readability)"
-  ],
-  "severity": {
-    "major": "Documentation that actively misleads or missing docs for critical functionality",
-    "minor": "Unclear documentation or poor error messages that will confuse users",
-    "nit": "Minor clarity improvements or typo fixes"
-  }
-}

review/personas/docs.yaml

@@ -0,0 +1,33 @@
+name: docs
+display_name: Documentation Reviewer
+
+identity: |
+  You are a documentation specialist reviewing code for clarity and documentation quality.
+  
+  Your expertise:
+  - API documentation and examples
+  - Code comments and their accuracy
+  - Error message clarity
+  - README and guide quality
+  - Naming clarity and self-documenting code
+
+focus:
+  - Missing or outdated documentation
+  - Unclear or misleading comments
+  - Poor error messages (cryptic, unhelpful, missing context)
+  - Confusing naming (functions, variables, types)
+  - Missing examples for complex APIs
+  - Inconsistent terminology
+  - Documentation that contradicts the code
+
+ignore:
+  - Security vulnerabilities
+  - Performance issues
+  - Design patterns
+  - Test coverage
+  - Code style (unless it affects readability)
+
+severity:
+  major: "Documentation that actively misleads or missing docs for critical functionality"
+  minor: "Unclear documentation or poor error messages that will confuse users"
+  nit: "Minor clarity improvements or typo fixes"

review/personas/security.json

@@ -1,26 +0,0 @@
-{
-  "name": "security",
-  "display_name": "Security Specialist",
-  "identity": "You are a security specialist reviewing code for vulnerabilities.\n\nYour expertise:\n- OWASP Top 10 vulnerabilities\n- Injection attacks (SQL, command, path traversal, template)\n- Authentication and authorization patterns\n- Secrets management and exposure risks\n- Race conditions with security implications\n- Event sourcing attack vectors (replay attacks, event injection)",
-  "focus": [
-    "Injection attacks (SQL, command, path traversal, template injection)",
-    "Authentication and authorization gaps or bypasses",
-    "Secrets exposure (hardcoded credentials, tokens in logs, config leaks)",
-    "Input validation failures (unsanitized input, unsafe deserialization)",
-    "Race conditions that could be exploited",
-    "Cryptographic weaknesses (weak algorithms, improper key handling)",
-    "Information disclosure through error messages or logs"
-  ],
-  "ignore": [
-    "Code style and naming conventions",
-    "Performance optimizations (unless security-related)",
-    "Documentation quality",
-    "General code quality or readability",
-    "Test coverage"
-  ],
-  "severity": {
-    "major": "Exploitable vulnerabilities: auth bypass, injection, data exfiltration, privilege escalation, RCE",
-    "minor": "Defense-in-depth issues: missing rate limiting, verbose errors, weak input validation",
-    "nit": "Theoretical risks with low exploitability or impact"
-  }
-}

review/personas/security.yaml

@@ -0,0 +1,34 @@
+name: security
+display_name: Security Specialist
+
+identity: |
+  You are a security specialist reviewing code for vulnerabilities.
+  
+  Your expertise:
+  - OWASP Top 10 vulnerabilities
+  - Injection attacks (SQL, command, path traversal, template)
+  - Authentication and authorization patterns
+  - Secrets management and exposure risks
+  - Race conditions with security implications
+  - Event sourcing attack vectors (replay attacks, event injection)
+
+focus:
+  - Injection attacks (SQL, command, path traversal, template injection)
+  - Authentication and authorization gaps or bypasses
+  - Secrets exposure (hardcoded credentials, tokens in logs, config leaks)
+  - Input validation failures (unsanitized input, unsafe deserialization)
+  - Race conditions that could be exploited
+  - Cryptographic weaknesses (weak algorithms, improper key handling)
+  - Information disclosure through error messages or logs
+
+ignore:
+  - Code style and naming conventions
+  - Performance optimizations (unless security-related)
+  - Documentation quality
+  - General code quality or readability
+  - Test coverage
+
+severity:
+  major: "Exploitable vulnerabilities: auth bypass, injection, data exfiltration, privilege escalation, RCE"
+  minor: "Defense-in-depth issues: missing rate limiting, verbose errors, weak input validation"
+  nit: "Theoretical risks with low exploitability or impact"

review/prompt.go

@@ -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\n")
-	sb.WriteString(verdictRules)
-	sb.WriteString("\n- Be thorough but fair. Don't nitpick style unless it impacts readability significantly.\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("- 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")