feat: add support for aichat as AI tool for release notesv0.8.0

- Add --ai-tool flag to release and sync commands
- Support both 'claude' and 'aichat' options (default: claude)
- Update GenerateAIReleaseNotes to handle both tools
- Add tool-specific error messages and hints
- Update documentation with usage examples

This allows users to choose between Claude CLI and aichat for
generating AI-powered release notes.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

7 files changed, 85 insertions, 24 deletions

diff --git a/CLAUDE.md b/CLAUDE.md
index c628c20..c9ab699 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -46,6 +46,9 @@ gitsyncer release create --auto
 
 # Create releases without AI notes
 gitsyncer release create --auto --no-ai-notes
+
+# Use aichat instead of claude for AI release notes
+gitsyncer release create --auto --ai-tool aichat
 ```
 
 Note: Release checking is enabled by default after sync operations. It will check for version tags (formats: vX.Y.Z, vX.Y, vX, X.Y.Z, X.Y, X) that don't have corresponding releases on GitHub/Codeberg and prompt for confirmation before creating them.
diff --git a/README.md b/README.md
index 88b6f89..f56554b 100644
--- a/README.md
+++ b/README.md
@@ -172,6 +172,9 @@ gitsyncer release create --update-existing
 
 # Create for specific repository without AI
 gitsyncer release create myproject --no-ai-notes
+
+# Use aichat instead of claude for AI release notes
+gitsyncer release create --ai-tool aichat
 ```
 
 ### Project Showcase
diff --git a/internal/cli/flags.go b/internal/cli/flags.go
index fb367cb..43d9fa3 100644
--- a/internal/cli/flags.go
+++ b/internal/cli/flags.go
@@ -35,6 +35,7 @@ type Flags struct {
 	AutoCreateReleases bool
 	AIReleaseNotes     bool
 	UpdateReleases     bool
+	AITool             string
 	
 	// Internal fields for batch run state management (not set by flags)
 	BatchRunStateManager *state.Manager
diff --git a/internal/cli/release.go b/internal/cli/release.go
index d7601f4..e05cbdd 100644
--- a/internal/cli/release.go
+++ b/internal/cli/release.go
@@ -59,6 +59,7 @@ func HandleCheckReleasesForRepo(cfg *config.Config, flags *Flags, repoName strin
 // HandleCheckReleasesForRepos checks for version tags without releases and creates them with confirmation
 func HandleCheckReleasesForRepos(cfg *config.Config, flags *Flags, repositories []string) int {
 	releaseManager := release.NewManager(flags.WorkDir)
+	releaseManager.SetAITool(flags.AITool)
 	
 	// Load persistent AI release notes cache
 	cacheFile := filepath.Join(flags.WorkDir, ".gitsyncer-ai-release-notes-cache.json")
diff --git a/internal/cmd/release.go b/internal/cmd/release.go
index f05005a..f9fa04f 100644
--- a/internal/cmd/release.go
+++ b/internal/cmd/release.go
@@ -12,6 +12,7 @@ var (
 	noAINotes      bool
 	updateExisting bool
 	templatePath   string
+	aiTool         string
 )
 
 var releaseCmd = &cobra.Command{
@@ -70,13 +71,17 @@ If no repository is specified, processes all configured repositories.`,
   gitsyncer release create --update-existing
   
   # Create for specific repository without AI
-  gitsyncer release create myproject --no-ai-notes`,
+  gitsyncer release create myproject --no-ai-notes
+  
+  # Use aichat instead of claude for AI release notes
+  gitsyncer release create --ai-tool aichat`,
 	Run: func(cmd *cobra.Command, args []string) {
 		flags := buildFlags()
 		flags.CheckReleases = true
 		flags.AutoCreateReleases = autoRelease
 		flags.AIReleaseNotes = !noAINotes
 		flags.UpdateReleases = updateExisting
+		flags.AITool = aiTool
 		
 		if len(args) > 0 {
 			// Create releases for specific repo
@@ -103,4 +108,5 @@ func init() {
 	releaseCreateCmd.Flags().BoolVar(&noAINotes, "no-ai-notes", false, "disable AI-generated release notes (AI notes are enabled by default)")
 	releaseCreateCmd.Flags().BoolVar(&updateExisting, "update-existing", false, "update existing releases with new AI-generated notes")
 	releaseCreateCmd.Flags().StringVar(&templatePath, "template", "", "custom template for release notes")
+	releaseCreateCmd.Flags().StringVar(&aiTool, "ai-tool", "claude", "AI tool to use for release notes (claude or aichat)")
 }
\ No newline at end of file
diff --git a/internal/cmd/sync.go b/internal/cmd/sync.go
index abedb7e..9fcf0fd 100644
--- a/internal/cmd/sync.go
+++ b/internal/cmd/sync.go
@@ -14,6 +14,7 @@ var (
 	noReleases     bool
 	autoCreate     bool
 	noAIReleaseNotes bool
+	syncAITool     string
 )
 
 var syncCmd = &cobra.Command{
@@ -39,7 +40,10 @@ var syncRepoCmd = &cobra.Command{
   gitsyncer sync repo myproject --dry-run
   
   # Sync without AI-generated release notes
-  gitsyncer sync repo myproject --no-ai-release-notes`,
+  gitsyncer sync repo myproject --no-ai-release-notes
+  
+  # Auto-create releases using aichat for AI notes
+  gitsyncer sync repo myproject --auto-create-releases --ai-tool aichat`,
 	Run: func(cmd *cobra.Command, args []string) {
 		flags := buildFlags()
 		flags.SyncRepo = args[0]
@@ -185,6 +189,7 @@ func init() {
 	syncCmd.PersistentFlags().BoolVar(&noReleases, "no-releases", false, "skip release checking after sync")
 	syncCmd.PersistentFlags().BoolVar(&autoCreate, "auto-create-releases", false, "automatically create releases without confirmation")
 	syncCmd.PersistentFlags().BoolVar(&noAIReleaseNotes, "no-ai-release-notes", false, "disable AI-generated release notes (AI notes are enabled by default)")
+	syncCmd.PersistentFlags().StringVar(&syncAITool, "ai-tool", "claude", "AI tool to use for release notes when auto-creating (claude or aichat)")
 }
 
 func buildFlags() *cli.Flags {
@@ -196,6 +201,7 @@ func buildFlags() *cli.Flags {
 		NoCheckReleases: noReleases,
 		AutoCreateReleases: autoCreate,
 		AIReleaseNotes: !noAIReleaseNotes,
+		AITool:       syncAITool,
 		CreateGitHubRepos: createRepos,
 		CreateCodebergRepos: createRepos,
 	}
diff --git a/internal/release/release.go b/internal/release/release.go
index ff84f4c..9d82900 100644
--- a/internal/release/release.go
+++ b/internal/release/release.go
@@ -30,6 +30,7 @@ type Manager struct {
 	workDir       string
 	githubToken   string
 	codebergToken string
+	aiTool        string
 }
 
 // NewManager creates a new release manager
@@ -49,6 +50,11 @@ func (m *Manager) SetCodebergToken(token string) {
 	m.codebergToken = token
 }
 
+// SetAITool sets the AI tool to use for release notes generation
+func (m *Manager) SetAITool(tool string) {
+	m.aiTool = tool
+}
+
 // isVersionTag checks if a tag name is a version tag
 // Supports formats: vX.Y.Z, vX.Y, vX, X.Y.Z, X.Y, X
 func isVersionTag(tag string) bool {
@@ -327,56 +333,91 @@ func (m *Manager) GenerateAIReleaseNotes(repoPath, repoName, tag string, allTags
 	prompt.WriteString("7. Format using Markdown\n")
 	prompt.WriteString("\nDo not include the version number in the title as it will be added automatically.")
 	
-	// Run Claude CLI
-	fmt.Println("  Running Claude CLI command:")
-	fmt.Println("  claude --model sonnet \"...\"")
+	// Run AI CLI
+	fmt.Printf("  Running %s CLI command:\n", m.aiTool)
+	if m.aiTool == "claude" || m.aiTool == "" {
+		fmt.Println("  claude --model sonnet \"...\"")
+	} else if m.aiTool == "aichat" {
+		fmt.Println("  aichat \"...\"")
+	}
 	fmt.Printf("  Prompt: Generate release notes for %s %s\n", repoName, tag)
 	fmt.Printf("  Prompt includes: %d commits, %.1fKB of code changes\n", len(commits), float64(len(diff))/1024)
 	fmt.Printf("  Total prompt length: %d characters\n", len(prompt.String()))
 	
-	// Check if claude CLI is available
-	if _, err := exec.LookPath("claude"); err != nil {
-		return "", fmt.Errorf("claude CLI not found in PATH. Please ensure claude CLI is installed and available")
+	// Determine which AI tool to use (default to claude if not set)
+	aiTool := m.aiTool
+	if aiTool == "" {
+		aiTool = "claude"
 	}
 	
-	// Skip auth check - it may hang or cause issues
-	// Users can manually run 'claude auth status' if needed
+	var cmd *exec.Cmd
 	
-	cmd := exec.Command("claude", "--model", "sonnet", prompt.String())
-	cmd.Env = append(os.Environ(), "CLAUDE_DEBUG=1") // Enable debug mode if supported
+	switch aiTool {
+	case "claude":
+		// Check if claude CLI is available
+		if _, err := exec.LookPath("claude"); err != nil {
+			return "", fmt.Errorf("claude CLI not found in PATH. Please ensure claude CLI is installed and available")
+		}
+		
+		// Skip auth check - it may hang or cause issues
+		// Users can manually run 'claude auth status' if needed
+		
+		cmd = exec.Command("claude", "--model", "sonnet", prompt.String())
+		cmd.Env = append(os.Environ(), "CLAUDE_DEBUG=1") // Enable debug mode if supported
+		
+	case "aichat":
+		// Check if aichat CLI is available
+		if _, err := exec.LookPath("aichat"); err != nil {
+			return "", fmt.Errorf("aichat CLI not found in PATH. Please ensure aichat CLI is installed and available")
+		}
+		
+		// For aichat, we need to pipe the prompt through stdin
+		cmd = exec.Command("aichat", prompt.String())
+		
+	default:
+		return "", fmt.Errorf("unsupported AI tool: %s (supported: claude, aichat)", aiTool)
+	}
 	
 	output, err := cmd.CombinedOutput() // Use CombinedOutput to capture stderr
 	if err != nil {
 		// Check if it's an exit error and print the output
 		if exitErr, ok := err.(*exec.ExitError); ok {
-			fmt.Printf("  Claude CLI failed with exit code %d\n", exitErr.ExitCode())
+			fmt.Printf("  %s CLI failed with exit code %d\n", aiTool, exitErr.ExitCode())
 			fmt.Printf("  Error output: %s\n", string(output))
 			
 			// Provide more helpful error messages based on common issues
 			errorMsg := string(output)
 			fmt.Printf("  Raw error output: %q\n", errorMsg) // Show with quotes to see whitespace
-			if strings.Contains(errorMsg, "Execution error") && len(errorMsg) < 50 {
-				fmt.Println("  Hint: This generic error often indicates:")
-				fmt.Println("    - Authentication issues (try: claude auth login)")
-				fmt.Println("    - Network connectivity problems")
-				fmt.Println("    - Rate limiting")
-				fmt.Println("    - Invalid model name (valid: opus, sonnet, haiku)")
-				fmt.Println("    - Try running manually: claude --model sonnet \"Hello\"")
+			
+			if aiTool == "claude" {
+				if strings.Contains(errorMsg, "Execution error") && len(errorMsg) < 50 {
+					fmt.Println("  Hint: This generic error often indicates:")
+					fmt.Println("    - Authentication issues (try: claude auth login)")
+					fmt.Println("    - Network connectivity problems")
+					fmt.Println("    - Rate limiting")
+					fmt.Println("    - Invalid model name (valid: opus, sonnet, haiku)")
+					fmt.Println("    - Try running manually: claude --model sonnet \"Hello\"")
+				}
+			} else if aiTool == "aichat" {
+				fmt.Println("  Hint: Common aichat issues:")
+				fmt.Println("    - Check configuration file (usually ~/.config/aichat/config.yaml)")
+				fmt.Println("    - Ensure API keys are set correctly")
+				fmt.Println("    - Try running manually: echo \"Hello\" | aichat \"Say hello back\"")
 			}
 			
-			return "", fmt.Errorf("claude CLI failed: %s", errorMsg)
+			return "", fmt.Errorf("%s CLI failed: %s", aiTool, errorMsg)
 		}
-		return "", fmt.Errorf("failed to run claude: %w", err)
+		return "", fmt.Errorf("failed to run %s: %w", aiTool, err)
 	}
 	
 	releaseNotes := strings.TrimSpace(string(output))
 	if releaseNotes == "" {
-		return "", fmt.Errorf("received empty release notes from claude")
+		return "", fmt.Errorf("received empty release notes from %s", aiTool)
 	}
 	
 	// Check for known error messages in the output
 	if releaseNotes == "Execution error" || strings.HasPrefix(releaseNotes, "Error:") {
-		return "", fmt.Errorf("claude CLI returned an error: %s", releaseNotes)
+		return "", fmt.Errorf("%s CLI returned an error: %s", aiTool, releaseNotes)
 	}
 	
 	// Add header