feat(create): add '--subdir <path>' flag to 'create' command

cmd/project/create.go

@@ -33,6 +33,7 @@ var createTemplateURLFlag string
 var createGitBranchFlag string
 var createAppNameFlag string
 var createListFlag bool
+var createSubdirFlag string
 
 // Handle to client's create function used for testing
 // TODO - Find best practice, such as using an Interface and Struct to create a client
@@ -66,6 +67,7 @@ name your app 'agent' (not create an AI Agent), use the --name flag instead.`,
 			{Command: "create agent my-agent-app", Meaning: "Create a new AI Agent app"},
 			{Command: "create my-project -t slack-samples/deno-hello-world", Meaning: "Start a new project from a specific template"},
 			{Command: "create --name my-project", Meaning: "Create a project named 'my-project'"},
+			{Command: "create my-project -t org/monorepo --subdir apps/my-app", Meaning: "Create from a subdirectory of a template"},
 		}),
 		Args: cobra.MaximumNArgs(2),
 		RunE: func(cmd *cobra.Command, args []string) error {
@@ -79,6 +81,7 @@ name your app 'agent' (not create an AI Agent), use the --name flag instead.`,
 	cmd.Flags().StringVarP(&createGitBranchFlag, "branch", "b", "", "name of git branch to checkout")
 	cmd.Flags().StringVarP(&createAppNameFlag, "name", "n", "", "name for your app (overrides the name argument)")
 	cmd.Flags().BoolVar(&createListFlag, "list", false, "list available app templates")
+	cmd.Flags().StringVar(&createSubdirFlag, "subdir", "", "subdirectory within the template to use as project root")
 
 	return cmd
 }
@@ -141,6 +144,7 @@ func runCreateCommand(clients *shared.ClientFactory, cmd *cobra.Command, args []
 		AppName:   appNameArg,
 		Template:  template,
 		GitBranch: createGitBranchFlag,
+		Subdir:    createSubdirFlag,
 	}
 	clients.EventTracker.SetAppTemplate(template.GetTemplatePath())
 

cmd/project/create_test.go

@@ -320,6 +320,52 @@ func TestCreateCommand(t *testing.T) {
 				cm.IO.AssertNotCalled(t, "SelectPrompt", mock.Anything, "Select an app:", mock.Anything, mock.Anything)
 			},
 		},
+		"passes subdir flag to create function": {
+			CmdArgs: []string{"--template", "slack-samples/bolt-js-starter-template", "--subdir", "apps/my-app"},
+			Setup: func(t *testing.T, ctx context.Context, cm *shared.ClientsMock, cf *shared.ClientFactory) {
+				cm.IO.On("SelectPrompt", mock.Anything, "Select an app:", mock.Anything, mock.Anything).
+					Return(
+						iostreams.SelectPromptResponse{
+							Flag:   true,
+							Option: "slack-samples/bolt-js-starter-template",
+						},
+						nil,
+					)
+				cm.IO.On("SelectPrompt", mock.Anything, "Select a language:", mock.Anything, mock.Anything).
+					Return(
+						iostreams.SelectPromptResponse{
+							Flag:   true,
+							Option: "slack-samples/bolt-js-starter-template",
+						},
+						nil,
+					)
+				createClientMock = new(CreateClientMock)
+				createClientMock.On("Create", mock.Anything, mock.Anything, mock.Anything, mock.Anything).Return("", nil)
+				CreateFunc = createClientMock.Create
+			},
+			ExpectedAsserts: func(t *testing.T, ctx context.Context, cm *shared.ClientsMock) {
+				template, err := create.ResolveTemplateURL("slack-samples/bolt-js-starter-template")
+				require.NoError(t, err)
+				expected := create.CreateArgs{
+					Template: template,
+					Subdir:   "apps/my-app",
+				}
+				createClientMock.AssertCalled(t, "Create", mock.Anything, mock.Anything, mock.Anything, expected)
+			},
+		},
+		"list flag ignores subdir": {
+			CmdArgs: []string{"--list", "--subdir", "foo"},
+			Setup: func(t *testing.T, ctx context.Context, cm *shared.ClientsMock, cf *shared.ClientFactory) {
+				createClientMock = new(CreateClientMock)
+				CreateFunc = createClientMock.Create
+			},
+			ExpectedOutputs: []string{
+				"Getting started",
+			},
+			ExpectedAsserts: func(t *testing.T, ctx context.Context, cm *shared.ClientsMock) {
+				createClientMock.AssertNotCalled(t, "Create", mock.Anything, mock.Anything, mock.Anything, mock.Anything)
+			},
+		},
 		"lists all templates with --list flag": {
 			CmdArgs: []string{"--list"},
 			Setup: func(t *testing.T, ctx context.Context, cm *shared.ClientsMock, cf *shared.ClientFactory) {

internal/pkg/create/create.go

@@ -50,6 +50,7 @@ type CreateArgs struct {
 	AppName   string
 	Template  Template
 	GitBranch string
+	Subdir    string
 }
 
 // Create will create a new Slack app on the file system and app manifest on the Slack API.
@@ -121,8 +122,19 @@ func Create(ctx context.Context, clients *shared.ClientFactory, log *logger.Logg
 	}))
 
 	// Create the project from a templateURL
-	if err := createApp(ctx, projectDirPath, createArgs.Template, createArgs.GitBranch, log, clients.Fs); err != nil {
-		return "", slackerror.Wrap(err, slackerror.ErrAppCreate)
+	subdir, err := normalizeSubdir(createArgs.Subdir)
+	if err != nil {
+		return "", err
+	}
+
+	if subdir != "" {
+		if err := createAppFromSubdir(ctx, projectDirPath, createArgs.Template, createArgs.GitBranch, subdir, log, clients.Fs); err != nil {
+			return "", slackerror.Wrap(err, slackerror.ErrAppCreate)
+		}
+	} else {
+		if err := createApp(ctx, projectDirPath, createArgs.Template, createArgs.GitBranch, log, clients.Fs); err != nil {
+			return "", slackerror.Wrap(err, slackerror.ErrAppCreate)
+		}
 	}
 
 	// Change into the project directory to configure defaults and dependencies
@@ -343,6 +355,60 @@ func createApp(ctx context.Context, dirPath string, template Template, gitBranch
 	return nil
 }
 
+// normalizeSubdir cleans the subdir path and returns "" if it resolves to root.
+func normalizeSubdir(subdir string) (string, error) {
+	if subdir == "" {
+		return "", nil
+	}
+	cleaned := filepath.Clean(subdir)
+	if cleaned == "." || cleaned == "/" {
+		return "", nil
+	}
+	if strings.HasPrefix(cleaned, "..") || filepath.IsAbs(cleaned) {
+		return "", slackerror.New(slackerror.ErrSubdirNotFound).
+			WithMessage("subdirectory path %q must be relative and within the template", subdir)
+	}
+	return cleaned, nil
+}
+
+// createAppFromSubdir clones the full template into a temp directory, then copies
+// only the specified subdirectory to the final project path.
+func createAppFromSubdir(ctx context.Context, dirPath string, template Template, gitBranch string, subdir string, log *logger.Logger, fs afero.Fs) error {
+	tmpDir, err := os.MkdirTemp("", "slack-create-*")
+	if err != nil {
+		return slackerror.Wrap(err, "failed to create temporary directory")
+	}
+	// Remove so createApp can create it fresh (go-git requires non-existent target)
+	os.Remove(tmpDir)
+	defer os.RemoveAll(tmpDir)
+
+	if err := createApp(ctx, tmpDir, template, gitBranch, log, fs); err != nil {
+		return err
+	}
+
+	subdirPath := filepath.Join(tmpDir, subdir)
+	info, err := os.Stat(subdirPath)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return slackerror.New(slackerror.ErrSubdirNotFound).
+				WithMessage("subdirectory %q was not found in the template", subdir).
+				WithRemediation("Check that the path exists in the template at %q", template.GetTemplatePath())
+		}
+		return slackerror.Wrap(err, "failed to access subdirectory")
+	}
+	if !info.IsDir() {
+		return slackerror.New(slackerror.ErrSubdirNotFound).
+			WithMessage("path %q in the template is not a directory", subdir)
+	}
+
+	return goutils.CopyDirectory(goutils.CopyDirectoryOpts{
+		Src:               subdirPath,
+		Dst:               dirPath,
+		IgnoreDirectories: []string{".git", ".venv", "node_modules"},
+		IgnoreFiles:       []string{".DS_Store"},
+	})
+}
+
 // InstallProjectDependencies installs the project runtime dependencies or
 // continues with next steps if that fails. You can specify the manifestSource
 // for the project configuration file (default: ManifestSourceLocal)

internal/pkg/create/create_test.go

@@ -17,11 +17,13 @@ package create
 import (
 	"fmt"
 	"net/http"
+	"os"
 	"path/filepath"
 	"testing"
 
 	"github.com/slackapi/slack-cli/internal/config"
 	"github.com/slackapi/slack-cli/internal/experiment"
+	"github.com/slackapi/slack-cli/internal/logger"
 	"github.com/slackapi/slack-cli/internal/shared"
 	"github.com/slackapi/slack-cli/internal/slackcontext"
 	"github.com/slackapi/slack-cli/internal/slackhttp"
@@ -183,6 +185,128 @@ func TestCreateGitArgs(t *testing.T) {
 	assert.Equal(t, expectedArgs, testGitArgs)
 }
 
+func TestNormalizeSubdir(t *testing.T) {
+	tests := map[string]struct {
+		input       string
+		expected    string
+		expectError bool
+	}{
+		"empty string returns empty": {
+			input:    "",
+			expected: "",
+		},
+		"dot returns empty": {
+			input:    ".",
+			expected: "",
+		},
+		"slash returns empty": {
+			input:    "/",
+			expected: "",
+		},
+		"simple subdir": {
+			input:    "pydantic-ai/",
+			expected: "pydantic-ai",
+		},
+		"dot-prefixed subdir": {
+			input:    "./my-app",
+			expected: "my-app",
+		},
+		"nested subdir": {
+			input:    "apps/my-app",
+			expected: "apps/my-app",
+		},
+		"parent traversal is rejected": {
+			input:       "../escape",
+			expectError: true,
+		},
+		"nested parent traversal is rejected": {
+			input:       "foo/../../escape",
+			expectError: true,
+		},
+	}
+	for name, tc := range tests {
+		t.Run(name, func(t *testing.T) {
+			result, err := normalizeSubdir(tc.input)
+			if tc.expectError {
+				assert.Error(t, err)
+			} else {
+				assert.NoError(t, err)
+				assert.Equal(t, tc.expected, result)
+			}
+		})
+	}
+}
+
+func TestCreateAppFromSubdir(t *testing.T) {
+	tests := map[string]struct {
+		setupTemplate func(t *testing.T) string
+		subdir        string
+		expectError   bool
+		errorContains string
+		expectFiles   []string
+	}{
+		"extracts subdirectory from local template": {
+			setupTemplate: func(t *testing.T) string {
+				tmpDir := t.TempDir()
+				// Create a subdirectory with a file
+				subdir := filepath.Join(tmpDir, "apps", "my-app")
+				require.NoError(t, os.MkdirAll(subdir, 0755))
+				require.NoError(t, os.WriteFile(filepath.Join(subdir, "manifest.json"), []byte(`{}`), 0644))
+				// Create a file at root that should NOT be copied
+				require.NoError(t, os.WriteFile(filepath.Join(tmpDir, "README.md"), []byte("root readme"), 0644))
+				return tmpDir
+			},
+			subdir:      "apps/my-app",
+			expectFiles: []string{"manifest.json"},
+		},
+		"returns error for nonexistent subdirectory": {
+			setupTemplate: func(t *testing.T) string {
+				return t.TempDir()
+			},
+			subdir:        "nonexistent",
+			expectError:   true,
+			errorContains: "was not found in the template",
+		},
+		"returns error when subdir path is a file": {
+			setupTemplate: func(t *testing.T) string {
+				tmpDir := t.TempDir()
+				require.NoError(t, os.WriteFile(filepath.Join(tmpDir, "not-a-dir"), []byte("file"), 0644))
+				return tmpDir
+			},
+			subdir:        "not-a-dir",
+			expectError:   true,
+			errorContains: "is not a directory",
+		},
+	}
+	for name, tc := range tests {
+		t.Run(name, func(t *testing.T) {
+			templateDir := tc.setupTemplate(t)
+			outputDir := t.TempDir()
+			// Remove output dir so CopyDirectory can create it
+			require.NoError(t, os.Remove(outputDir))
+
+			template := Template{path: templateDir, isLocal: true}
+			log := logger.New(func(event *logger.LogEvent) {})
+			fs := afero.NewOsFs()
+
+			err := createAppFromSubdir(t.Context(), outputDir, template, "", tc.subdir, log, fs)
+
+			if tc.expectError {
+				assert.Error(t, err)
+				if tc.errorContains != "" {
+					assert.Contains(t, err.Error(), tc.errorContains)
+				}
+			} else {
+				assert.NoError(t, err)
+				for _, f := range tc.expectFiles {
+					_, statErr := os.Stat(filepath.Join(outputDir, f))
+					assert.NoError(t, statErr, "expected file %s to exist", f)
+				}
+			}
+		})
+	}
+}
+
 func Test_Create_installProjectDependencies(t *testing.T) {
 	tests := map[string]struct {
 		experiments            []string

internal/slackerror/errors.go

@@ -225,6 +225,7 @@ const (
 	ErrSocketConnection                              = "socket_connection_error"
 	ErrScopesExceedAppConfig                         = "scopes_exceed_app_config"
 	ErrStreamingActivityLogs                         = "streaming_activity_logs_error"
+	ErrSubdirNotFound                                = "subdir_not_found"
 	ErrSurveyConfigNotFound                          = "survey_config_not_found"
 	ErrSystemConfigIDNotFound                        = "system_config_id_not_found"
 	ErrSystemRequirementsFailed                      = "system_requirements_failed"
@@ -1391,6 +1392,11 @@ Otherwise start your app for local development with: %s`,
 		Message: "Failed to stream the most recent activity logs",
 	},
 
+	ErrSubdirNotFound: {
+		Code:    ErrSubdirNotFound,
+		Message: "The specified subdirectory was not found in the template repository",
+	},
+
 	ErrSurveyConfigNotFound: {
 		Code:    ErrSurveyConfigNotFound,
 		Message: "Survey config not found",