feat(config): configurable worktree prompt branch policy

docs/reference/configuration.md

@@ -18,6 +18,8 @@ agent:
   cliPath: ""        # optional path to CLI binary
 worktree:
   setup: "npm install"
+  alwaysPrompt: false
+  promptBranchPattern: "^(main|master)$"
 onComplete:
   push: true
   createPR: true
@@ -30,9 +32,13 @@ onComplete:
 | `agent.provider` | string | `"claude"` | Agent CLI to use: `claude`, `codex`, `opencode`, or `cursor` |
 | `agent.cliPath` | string | `""` | Optional path to the agent binary (e.g. `/usr/local/bin/opencode`). If empty, Chief uses the provider name from PATH. |
 | `worktree.setup` | string | `""` | Shell command to run in new worktrees (e.g., `npm install`, `go mod download`) |
+| `worktree.alwaysPrompt` | bool | `false` | When true, Chief always prompts about creating a git worktree before starting a loop, regardless of the current branch name. Overrides `promptBranchPattern`. |
+| `worktree.promptBranchPattern` | string (regex) | `"^(main\|master)$"` | Regular expression matched against the current branch name. When it matches, Chief prompts about creating a git worktree. Empty string disables matching. Ignored when `alwaysPrompt` is true. Invalid regex causes Chief to fail at startup with an error naming the offending field. Patterns use Go's RE2 syntax — lookarounds and backreferences are not supported. |
 | `onComplete.push` | bool | `false` | Automatically push the branch to remote when a PRD completes |
 | `onComplete.createPR` | bool | `false` | Automatically create a pull request when a PRD completes (requires `gh` CLI) |
 
+If you write `promptBranchPattern: ""` explicitly, Chief skips branch-name matching entirely; only `alwaysPrompt` will trigger the prompt. Default regex: `^(main|master)$`. The `\|` shown in the default column above is Markdown escaping for the table separator; the actual regex value uses an unescaped `|`.
+
 ### Example Configurations
 
 **Minimal (defaults):**
@@ -55,13 +61,27 @@ onComplete:
   createPR: true
 ```
 
+**Prompt for worktree on main, master, or any release branch:**
+
+```yaml
+worktree:
+  promptBranchPattern: "^(main|master|release/.*)$"
+```
+
+**Always prompt for a worktree:**
+
+```yaml
+worktree:
+  alwaysPrompt: true
+```
+
 ## Settings TUI
 
-Press `,` from any view in the TUI to open the Settings overlay. This provides an interactive way to view and edit all config values.
+Press `,` from any view in the TUI to open the Settings overlay. This provides an interactive way to view and edit a subset of common config values.
 
 Settings are organized by section:
 
-- **Worktree** — Setup command (string, editable inline)
+- **Worktree** — Setup command (string, editable inline), Always prompt for worktree (toggle), Prompt branch pattern (regex, editable inline; invalid regex is rejected with an inline error so the editor stays open)
 - **On Complete** — Push to remote (toggle), Create pull request (toggle)
 
 Changes are saved immediately to `.chief/config.yaml` on every edit.

internal/agent/resolve_test.go

@@ -188,15 +188,15 @@ func TestCheckInstalled_found(t *testing.T) {
 func TestResolve_configFile(t *testing.T) {
 	dir := t.TempDir()
 	cfgPath := filepath.Join(dir, ".chief", "config.yaml")
-	if err := os.MkdirAll(filepath.Dir(cfgPath), 0o755); err != nil {
+	if err := os.MkdirAll(filepath.Dir(cfgPath), 0755); err != nil {
 		t.Fatal(err)
 	}
 	const yamlContent = `
 agent:
   provider: codex
   cliPath: /usr/local/bin/codex
 `
-	if err := os.WriteFile(cfgPath, []byte(yamlContent), 0o644); err != nil {
+	if err := os.WriteFile(cfgPath, []byte(yamlContent), 0644); err != nil {
 		t.Fatal(err)
 	}
 	cfg, err := config.Load(dir)

internal/config/config.go

@@ -1,8 +1,10 @@
 package config
 
 import (
+	"fmt"
 	"os"
 	"path/filepath"
+	"regexp"
 
 	"gopkg.in/yaml.v3"
 )
@@ -14,6 +16,8 @@ type Config struct {
 	Worktree   WorktreeConfig   `yaml:"worktree"`
 	OnComplete OnCompleteConfig `yaml:"onComplete"`
 	Agent      AgentConfig      `yaml:"agent"`
+
+	promptBranchRegex *regexp.Regexp
 }
 
 // AgentConfig holds agent CLI settings (Claude, Codex, OpenCode, or Cursor).
@@ -24,7 +28,9 @@ type AgentConfig struct {
 
 // WorktreeConfig holds worktree-related settings.
 type WorktreeConfig struct {
-	Setup string `yaml:"setup"`
+	Setup               string `yaml:"setup"`
+	AlwaysPrompt        bool   `yaml:"alwaysPrompt"`
+	PromptBranchPattern string `yaml:"promptBranchPattern"`
 }
 
 // OnCompleteConfig holds post-completion automation settings.
@@ -35,7 +41,54 @@ type OnCompleteConfig struct {
 
 // Default returns a Config with zero-value defaults.
 func Default() *Config {
-	return &Config{}
+	cfg := &Config{
+		Worktree: WorktreeConfig{
+			PromptBranchPattern: "^(main|master)$",
+		},
+	}
+	if err := cfg.Validate(); err != nil {
+		panic(fmt.Sprintf("config: default config failed to validate: %v", err))
+	}
+	return cfg
+}
+
+// Validate compiles derived config state (e.g., the prompt-branch regex
+// cache) and reports configuration errors. Idempotent — safe to call
+// multiple times. Callers must call Validate after mutating Config fields
+// that affect derived state.
+func (c *Config) Validate() error {
+	return c.compilePromptRegex()
+}
+
+// ValidateBranchPattern compiles pattern as a worktree prompt-branch regex.
+// An empty pattern is valid and returns (nil, nil). The returned compile
+// error is bare; callers add field-name context when surfacing it.
+func ValidateBranchPattern(pattern string) (*regexp.Regexp, error) {
+	if pattern == "" {
+		return nil, nil
+	}
+	return regexp.Compile(pattern)
+}
+
+// compilePromptRegex compiles and caches the worktree prompt-branch regex.
+func (c *Config) compilePromptRegex() error {
+	re, err := ValidateBranchPattern(c.Worktree.PromptBranchPattern)
+	if err != nil {
+		return fmt.Errorf("invalid worktree.promptBranchPattern %q: %w", c.Worktree.PromptBranchPattern, err)
+	}
+	c.promptBranchRegex = re
+	return nil
+}
+
+// ShouldPromptForWorktree reports whether Chief should prompt the user about using a git worktree for the given branch.
+func (c *Config) ShouldPromptForWorktree(branch string) bool {
+	if c.Worktree.AlwaysPrompt {
+		return true
+	}
+	if c.promptBranchRegex == nil {
+		return false
+	}
+	return c.promptBranchRegex.MatchString(branch)
 }
 
 // configPath returns the full path to the config file.
@@ -66,16 +119,23 @@ func Load(baseDir string) (*Config, error) {
 	if err := yaml.Unmarshal(data, cfg); err != nil {
 		return nil, err
 	}
+	if err := cfg.Validate(); err != nil {
+		return nil, err
+	}
 
 	return cfg, nil
 }
 
 // Save writes the config to .chief/config.yaml.
 func Save(baseDir string, cfg *Config) error {
+	if err := cfg.Validate(); err != nil {
+		return err
+	}
+
 	path := configPath(baseDir)
 
 	// Ensure directory exists
-	if err := os.MkdirAll(filepath.Dir(path), 0o755); err != nil {
+	if err := os.MkdirAll(filepath.Dir(path), 0755); err != nil {
 		return err
 	}
 
@@ -84,5 +144,5 @@ func Save(baseDir string, cfg *Config) error {
 		return err
 	}
 
-	return os.WriteFile(path, data, 0o644)
+	return os.WriteFile(path, data, 0644)
 }