feat(config): support non-hidden repo config file

README.md

@@ -60,7 +60,7 @@ Configuration is layered. Later layers override earlier ones:
 | 1 (lowest) | System git config (`/etc/gitconfig`) |
 | 2 | Global git config (`~/.gitconfig`) |
 | 3 | User TOML (`~/.config/git-ai-commit/config.toml`) |
-| 4 | Repo TOML (`.git-ai-commit.toml` at repo root) |
+| 4 | Repo TOML (`git-ai-commit.toml` or `.git-ai-commit.toml` at repo root) |
 | 5 | Local git config (`.git/config`) |
 | 6 | Worktree git config |
 | 7 (highest) | Command-line flags |
@@ -69,7 +69,7 @@ Repository TOML config is applied only after an initial trust prompt, since it i
 
 ### TOML config files
 
-`~/.config/git-ai-commit/config.toml` for user-wide defaults, `.git-ai-commit.toml` at the repo root for project defaults.
+`~/.config/git-ai-commit/config.toml` for user-wide defaults, `git-ai-commit.toml` (or `.git-ai-commit.toml`) at the repo root for project defaults.
 
 Example: Use Codex with Conventional Commits by default
 

internal/config/config.go

@@ -309,6 +309,8 @@ func configPath() (string, error) {
 	return filepath.Join(dir, "config.toml"), nil
 }
 
+var repoConfigNames = []string{"git-ai-commit.toml", ".git-ai-commit.toml"}
+
 func repoConfigPath() (string, string, error) {
 	cmd := exec.Command("git", "rev-parse", "--show-toplevel")
 	var stdout bytes.Buffer
@@ -320,18 +322,21 @@ func repoConfigPath() (string, string, error) {
 	if root == "" {
 		return "", "", nil
 	}
-	path := filepath.Join(root, ".git-ai-commit.toml")
-	info, err := os.Stat(path)
-	if err != nil {
-		if os.IsNotExist(err) {
-			return root, "", nil
+	for _, name := range repoConfigNames {
+		path := filepath.Join(root, name)
+		info, err := os.Stat(path)
+		if err != nil {
+			if os.IsNotExist(err) {
+				continue
+			}
+			return "", "", fmt.Errorf("stat repo config: %w", err)
 		}
-		return "", "", fmt.Errorf("stat repo config: %w", err)
-	}
-	if info.IsDir() {
-		return "", "", fmt.Errorf("repo config is a directory: %s", path)
+		if info.IsDir() {
+			return "", "", fmt.Errorf("repo config is a directory: %s", path)
+		}
+		return root, path, nil
 	}
-	return root, path, nil
+	return root, "", nil
 }
 
 func LoadPromptPreset(name string) (string, error) {

internal/config/config_test.go

@@ -509,6 +509,69 @@ func containsHelper(s, substr string) bool {
 	return false
 }
 
+func TestNonHiddenRepoConfig(t *testing.T) {
+	base := t.TempDir()
+	repo := filepath.Join(base, "repo")
+	if err := os.MkdirAll(repo, 0o755); err != nil {
+		t.Fatalf("mkdir repo: %v", err)
+	}
+	runGit(t, repo, "init")
+
+	repoConfig := filepath.Join(repo, "git-ai-commit.toml")
+	if err := os.WriteFile(repoConfig, []byte("engine = 'codex'\n"), 0o644); err != nil {
+		t.Fatalf("write repo config: %v", err)
+	}
+
+	configHome := t.TempDir()
+	t.Setenv("XDG_CONFIG_HOME", configHome)
+
+	trustRepoConfig(t, repo, repoConfig)
+
+	withDir(t, repo, func() {
+		cfg, err := Load()
+		if err != nil {
+			t.Fatalf("Load error: %v", err)
+		}
+		if cfg.DefaultEngine != "codex" {
+			t.Fatalf("DefaultEngine = %q, want codex", cfg.DefaultEngine)
+		}
+	})
+}
+
+func TestNonHiddenRepoConfigPrecedence(t *testing.T) {
+	base := t.TempDir()
+	repo := filepath.Join(base, "repo")
+	if err := os.MkdirAll(repo, 0o755); err != nil {
+		t.Fatalf("mkdir repo: %v", err)
+	}
+	runGit(t, repo, "init")
+
+	// Both files exist; non-hidden should win
+	nonHidden := filepath.Join(repo, "git-ai-commit.toml")
+	if err := os.WriteFile(nonHidden, []byte("engine = 'codex'\n"), 0o644); err != nil {
+		t.Fatalf("write non-hidden config: %v", err)
+	}
+	hidden := filepath.Join(repo, ".git-ai-commit.toml")
+	if err := os.WriteFile(hidden, []byte("engine = 'gemini'\n"), 0o644); err != nil {
+		t.Fatalf("write hidden config: %v", err)
+	}
+
+	configHome := t.TempDir()
+	t.Setenv("XDG_CONFIG_HOME", configHome)
+
+	trustRepoConfig(t, repo, nonHidden)
+
+	withDir(t, repo, func() {
+		cfg, err := Load()
+		if err != nil {
+			t.Fatalf("Load error: %v", err)
+		}
+		if cfg.DefaultEngine != "codex" {
+			t.Fatalf("DefaultEngine = %q, want codex (non-hidden should take precedence)", cfg.DefaultEngine)
+		}
+	})
+}
+
 func trustRepoConfig(t *testing.T, repoRoot, repoConfigPath string) {
 	t.Helper()
 	data, err := os.ReadFile(repoConfigPath)