MCP: Create AppKit Template (#4007)

## Changes

* Added AppKit template
* Removed tRPC template
* Introduced go templates for interpolating files from the template
* Removed `--allow-deployment` configuration. It's defaulting to `true`
now.
* The new template features
  * AppKit support (bundled dependency)  
  * Playwright for E2E smoke test validation
  * DABs pre-configured (not currently used but will be in the future)

## Why
<!-- Why are these changes needed? Provide the context that the reviewer
might be missing.
For example, were there any decisions behind the change that are not
reflected in the code itself? -->

## Tests

Creating dozens of NYC taxi apps

<!-- If your PR needs to be included in the release notes for next
release,
add a separate entry in NEXT_CHANGELOG.md as part of your PR. -->

---------

Co-authored-by: Pieter Noordhuis <[email protected]>

Author: fjakobs

.wsignore

@@ -10,6 +10,8 @@ python/docs/images/databricks-logo.svg
 # Binary files
 **/*.zip
 **/*.whl
+**/*.png
+**/*.tgz
 
 # new lines are recorded differently on windows and unix.
 # In unix: "raw_body": "hello, world\n"

experimental/apps-mcp/README.md

@@ -10,7 +10,7 @@ extensive validation to ensure high-quality outputs.
 
 **How it works:**
 1. **Explore your data** - Query Databricks catalogs, schemas, and tables to understand your data
-2. **Generate the app** - Scaffold a full-stack TypeScript application (tRPC + React) with proper structure
+2. **Generate the app** - Scaffold a full-stack TypeScript application with proper structure
 3. **Customize with AI** - Use workspace tools to read, write, and edit files naturally through conversation
 4. **Validate rigorously** - Run builds, type checks, and tests to ensure quality
 5. **Deploy confidently** - Push validated apps directly to Databricks Apps platform
@@ -91,7 +91,7 @@ Understand your Databricks data before building:
 
 Create the application structure:
 
-- **`scaffold_data_app`** - Generate a full-stack TypeScript application
+- **`scaffold_databricks_app`** - Generate a full-stack TypeScript application
   - Modern stack: Node.js, TypeScript, React, tRPC
   - Pre-configured build system, linting, and testing
   - Production-ready project structure
@@ -103,7 +103,7 @@ Create the application structure:
 
 Ensure production-readiness before deployment:
 
-- **`validate_data_app`** - Comprehensive validation
+- **`validate_databricks_app`** - Comprehensive validation
   - Build verification (npm build)
   - Type checking (TypeScript compiler)
   - Test execution (full test suite)
@@ -112,7 +112,7 @@ Ensure production-readiness before deployment:
 
 ### 4. Deployment (Production Release)
 
-Deploy validated applications to Databricks (enable with `--allow-deployment`):
+Deploy validated applications to Databricks:
 
 - **`deploy_databricks_app`** - Push to Databricks Apps platform
   - Automatic deployment configuration
@@ -290,9 +290,6 @@ databricks experimental apps-mcp --warehouse-id <warehouse-id>
 
 # Enable workspace tools
 databricks experimental apps-mcp --warehouse-id <warehouse-id> --with-workspace-tools
-
-# Enable deployment
-databricks experimental apps-mcp --warehouse-id <warehouse-id> --allow-deployment
 ```
 
 ### CLI Flags
@@ -301,7 +298,6 @@ databricks experimental apps-mcp --warehouse-id <warehouse-id> --allow-deploymen
 |------|-------------|---------|
 | `--warehouse-id` | Databricks SQL Warehouse ID (required) | - |
 | `--with-workspace-tools` | Enable workspace file operations | `false` |
-| `--allow-deployment` | Enable deployment operations | `false` |
 | `--help` | Show help | - |
 
 ### Environment Variables
@@ -312,7 +308,6 @@ databricks experimental apps-mcp --warehouse-id <warehouse-id> --allow-deploymen
 | `DATABRICKS_TOKEN` | Databricks personal access token | `dapi...` |
 | `WAREHOUSE_ID` | Databricks SQL warehouse ID (preferred) | `abc123def456` |
 | `DATABRICKS_WAREHOUSE_ID` | Alternative name for warehouse ID | `abc123def456` |
-| `ALLOW_DEPLOYMENT` | Enable deployment operations | `true` or `false` |
 | `WITH_WORKSPACE_TOOLS` | Enable workspace tools | `true` or `false` |
 
 ### Authentication

experimental/apps-mcp/cmd/apps_mcp.go

@@ -9,7 +9,6 @@ import (
 
 func NewMcpCmd() *cobra.Command {
 	var warehouseID string
-	var allowDeployment bool
 	var withWorkspaceTools bool
 
 	cmd := &cobra.Command{
@@ -21,23 +20,19 @@ func NewMcpCmd() *cobra.Command {
 The MCP server exposes the following capabilities:
 - Databricks integration (query catalogs, schemas, tables, execute SQL)
 - Project scaffolding (generate full-stack TypeScript applications)
-- Sandboxed execution (isolated file/command execution)
+- Deployment to Databricks Apps
 
 The server communicates via stdio using the Model Context Protocol.`,
 		Example: `  # Start MCP server with required warehouse
   databricks experimental apps-mcp --warehouse-id abc123
 
   # Start with workspace tools enabled
-  databricks experimental apps-mcp --warehouse-id abc123 --with-workspace-tools
-
-  # Start with deployment tools enabled
-  databricks experimental apps-mcp --warehouse-id abc123 --allow-deployment`,
+  databricks experimental apps-mcp --warehouse-id abc123 --with-workspace-tools`,
 		RunE: func(cmd *cobra.Command, args []string) error {
 			ctx := cmd.Context()
 
 			// Build MCP config from flags
 			cfg := &mcplib.Config{
-				AllowDeployment:    allowDeployment,
 				WithWorkspaceTools: withWorkspaceTools,
 				IoConfig: &mcplib.IoConfig{
 					Validation: &mcplib.ValidationConfig{},
@@ -62,7 +57,6 @@ The server communicates via stdio using the Model Context Protocol.`,
 
 	// Define flags
 	cmd.Flags().StringVar(&warehouseID, "warehouse-id", "", "Databricks SQL Warehouse ID")
-	cmd.Flags().BoolVar(&allowDeployment, "allow-deployment", false, "Enable deployment tools")
 	cmd.Flags().BoolVar(&withWorkspaceTools, "with-workspace-tools", false, "Enable workspace tools (file operations, bash, grep, glob)")
 
 	cmd.AddCommand(newInstallCmd())

experimental/apps-mcp/lib/config.go

@@ -5,7 +5,6 @@ package mcp
 // Config holds MCP server configuration.
 // Configuration is populated from CLI flags and Databricks client context.
 type Config struct {
-	AllowDeployment    bool
 	WithWorkspaceTools bool
 	IoConfig           *IoConfig
 }
@@ -41,7 +40,6 @@ func DefaultConfig() *Config {
 	validationCfg.SetDefaults()
 
 	return &Config{
-		AllowDeployment:    false,
 		WithWorkspaceTools: false,
 		IoConfig: &IoConfig{
 			Template: &TemplateConfig{

experimental/apps-mcp/lib/prompts/initialization_message.tmpl

@@ -1,9 +1,9 @@
 Your session in Databricks MCP has been successfully initialized. Here are the guidelines to follow while working on projects using databricks_mcp tools:
 
 ## Project State Management:
-This project uses a state file (`.edda_state`) managed by edda MCP to enforce the correct workflow order:
-1. **Scaffolded**: `scaffold_data_app` creates project structure from template (starts in this state)
-2. **Validated**: `validate_data_app` runs build + tests, computes BLAKE3 checksum of package.json and all core source files
+This project uses a state file (`.edda_state`) managed by Databricks MCP to enforce the correct workflow order:
+1. **Scaffolded**: `scaffold_databricks_app` creates project structure from template (starts in this state)
+2. **Validated**: `validate_databricks_app` runs build + tests, computes a checksum of package.json and all core source files
 3. **Deployed**: `deploy_databricks_app` deploys to Databricks Apps, but ONLY if checksum hasn't changed since validation
 
 Re-validation is allowed (Deployed → Validated) to update the checksum after intentional changes. The databricks_mcp tools enforce these state transitions and prevent invalid state changes.
@@ -15,4 +15,4 @@ Re-validation is allowed (Deployed → Validated) to update the checksum after i
 - When working with Databricks or other services, use real API calls in tests (no mocks) to verify end-to-end functionality, unless explicitly instructed otherwise. It can be done on subset of data if applicable.
 - Do NOT create summary files, reports, or README unless explicitly requested
 - When not sure about the user's intent, ask clarifying questions before proceeding. For example, if user asks for "a data app to analyze sales data", ask for more details on data sources and analysis goals. Do not make assumptions regarding their needs and data sources.
-- However, stick to the technical stack initialized by the `scaffold_data_app` as it has been approved by the management and battle-tested in production.
+- However, stick to the technical stack initialized by the `scaffold_databricks_app` as it has been approved by the management and battle-tested in production.

experimental/apps-mcp/lib/providers/databricks/deployment.go

@@ -3,12 +3,12 @@ package databricks
 import (
 	"context"
 	"fmt"
+	"os"
 	"os/exec"
 	"time"
 
 	mcp "github.com/databricks/cli/experimental/apps-mcp/lib"
 	"github.com/databricks/cli/experimental/apps-mcp/lib/middlewares"
-	"github.com/databricks/cli/libs/cmdctx"
 	"github.com/databricks/databricks-sdk-go/service/apps"
 	"github.com/databricks/databricks-sdk-go/service/iam"
 )
@@ -20,18 +20,13 @@ func GetSourcePath(app *apps.App) string {
 	return app.DefaultSourceCodePath
 }
 
-func GetAppInfo(ctx context.Context, cfg *mcp.Config, name string) (*apps.App, error) {
-	w := cmdctx.WorkspaceClient(ctx)
-	app, err := w.Apps.GetByName(ctx, name)
-	if err != nil {
-		return nil, fmt.Errorf("failed to get app info: %w", err)
-	}
-
-	return app, nil
+func GetAppInfo(ctx context.Context, name string) (*apps.App, error) {
+	w := middlewares.MustGetDatabricksClient(ctx)
+	return w.Apps.GetByName(ctx, name)
 }
 
-func CreateApp(ctx context.Context, cfg *mcp.Config, createAppRequest *apps.CreateAppRequest) (*apps.App, error) {
-	w := cmdctx.WorkspaceClient(ctx)
+func CreateApp(ctx context.Context, createAppRequest *apps.CreateAppRequest) (*apps.App, error) {
+	w := middlewares.MustGetDatabricksClient(ctx)
 
 	wait, err := w.Apps.Create(ctx, *createAppRequest)
 	if err != nil {
@@ -47,7 +42,10 @@ func CreateApp(ctx context.Context, cfg *mcp.Config, createAppRequest *apps.Crea
 }
 
 func GetUserInfo(ctx context.Context, cfg *mcp.Config) (*iam.User, error) {
-	w := cmdctx.WorkspaceClient(ctx)
+	w, err := middlewares.GetDatabricksClient(ctx)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get databricks client: %w", err)
+	}
 	user, err := w.CurrentUser.Me(ctx)
 	if err != nil {
 		return nil, fmt.Errorf("failed to get user info: %w", err)
@@ -56,8 +54,9 @@ func GetUserInfo(ctx context.Context, cfg *mcp.Config) (*iam.User, error) {
 	return user, nil
 }
 
-func SyncWorkspace(appInfo *apps.App, sourceDir string) error {
+func SyncWorkspace(ctx context.Context, appInfo *apps.App, sourceDir string) error {
 	targetPath := GetSourcePath(appInfo)
+	host := middlewares.MustGetDatabricksClient(ctx).Config.Host
 
 	cmd := exec.Command(
 		"databricks",
@@ -68,6 +67,9 @@ func SyncWorkspace(appInfo *apps.App, sourceDir string) error {
 		targetPath,
 	)
 	cmd.Dir = sourceDir
+	env := os.Environ()
+	env = append(env, "DATABRICKS_HOST="+host)
+	cmd.Env = env
 
 	output, err := cmd.CombinedOutput()
 	if err != nil {
@@ -78,7 +80,10 @@ func SyncWorkspace(appInfo *apps.App, sourceDir string) error {
 }
 
 func DeployApp(ctx context.Context, cfg *mcp.Config, appInfo *apps.App) error {
-	w := cmdctx.WorkspaceClient(ctx)
+	w, err := middlewares.GetDatabricksClient(ctx)
+	if err != nil {
+		return fmt.Errorf("failed to get databricks client: %w", err)
+	}
 	sourcePath := GetSourcePath(appInfo)
 
 	req := apps.CreateAppDeploymentRequest{
@@ -109,8 +114,8 @@ func ResourcesFromEnv(ctx context.Context, cfg *mcp.Config) (*apps.AppResource,
 	}
 
 	return &apps.AppResource{
-		Name:        "base",
-		Description: "template resources",
+		Name:        "warehouse",
+		Description: "Warehouse to use for the app",
 		SqlWarehouse: &apps.AppResourceSqlWarehouse{
 			Id:         warehouseID,
 			Permission: apps.AppResourceSqlWarehouseSqlWarehousePermissionCanUse,

experimental/apps-mcp/lib/providers/deployment/provider.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"fmt"
 	"os"
-	"os/exec"
 	"path/filepath"
 	"time"
 
@@ -19,14 +18,10 @@ import (
 )
 
 func init() {
-	// Register deployment provider with conditional enablement based on AllowDeployment
+	// Register deployment provider
 	providers.Register("deployment", func(ctx context.Context, cfg *mcp.Config, sess *session.Session) (providers.Provider, error) {
 		return NewProvider(ctx, cfg, sess)
-	}, providers.ProviderConfig{
-		EnabledWhen: func(cfg *mcp.Config) bool {
-			return cfg.AllowDeployment
-		},
-	})
+	}, providers.ProviderConfig{})
 }
 
 const deployRetries = 3
@@ -150,7 +145,7 @@ func (p *Provider) deployDatabricksApp(ctx context.Context, args *DeployDatabric
 	if !hasChecksum {
 		return &DeployResult{
 			Success: false,
-			Message: "Project must be validated before deployment. Run validate_data_app first.",
+			Message: "Project must be validated before deployment. Run validate_databricks_app first.",
 			AppName: args.Name,
 		}, nil
 	}
@@ -167,25 +162,7 @@ func (p *Provider) deployDatabricksApp(ctx context.Context, args *DeployDatabric
 	if !checksumValid {
 		return &DeployResult{
 			Success: false,
-			Message: "Project files changed since validation. Re-run validate_data_app before deployment.",
-			AppName: args.Name,
-		}, nil
-	}
-
-	log.Infof(ctx, "Installing dependencies: work_dir=%s", workPath)
-	if err := p.runCommand(workPath, "npm", "install"); err != nil {
-		return &DeployResult{
-			Success: false,
-			Message: fmt.Sprintf("Failed to install dependencies: %v", err),
-			AppName: args.Name,
-		}, nil
-	}
-
-	log.Infof(ctx, "Building frontend: work_dir=%s", workPath)
-	if err := p.runCommand(workPath, "npm", "run", "build"); err != nil {
-		return &DeployResult{
-			Success: false,
-			Message: fmt.Sprintf("Failed to build frontend: %v", err),
+			Message: "Project files changed since validation. Re-run validate_databricks_app before deployment.",
 			AppName: args.Name,
 		}, nil
 	}
@@ -199,11 +176,10 @@ func (p *Provider) deployDatabricksApp(ctx context.Context, args *DeployDatabric
 		}, nil
 	}
 
-	serverDir := filepath.Join(workPath, "server")
 	syncStart := time.Now()
-	log.Infof(ctx, "Syncing workspace: source=%s, target=%s", serverDir, databricks.GetSourcePath(appInfo))
+	log.Infof(ctx, "Syncing workspace: source=%s, target=%s", workPath, databricks.GetSourcePath(appInfo))
 
-	if err := databricks.SyncWorkspace(appInfo, serverDir); err != nil {
+	if err := databricks.SyncWorkspace(ctx, appInfo, workPath); err != nil {
 		return &DeployResult{
 			Success: false,
 			Message: fmt.Sprintf("Failed to sync workspace: %v", err),
@@ -265,7 +241,7 @@ func (p *Provider) deployDatabricksApp(ctx context.Context, args *DeployDatabric
 }
 
 func (p *Provider) getOrCreateApp(ctx context.Context, name, description string, force bool) (*apps.App, error) {
-	appInfo, err := databricks.GetAppInfo(ctx, p.config, name)
+	appInfo, err := databricks.GetAppInfo(ctx, name)
 	if err == nil {
 		log.Infof(ctx, "Found existing app: name=%s", name)
 
@@ -302,19 +278,7 @@ func (p *Provider) getOrCreateApp(ctx context.Context, name, description string,
 		},
 	}
 
-	return databricks.CreateApp(ctx, p.config, createApp)
-}
-
-func (p *Provider) runCommand(dir, name string, args ...string) error {
-	cmd := exec.Command(name, args...)
-	cmd.Dir = dir
-
-	output, err := cmd.CombinedOutput()
-	if err != nil {
-		return fmt.Errorf("%s failed: %w (output: %s)", name, err, string(output))
-	}
-
-	return nil
+	return databricks.CreateApp(ctx, createApp)
 }
 
 func formatDeployResult(result *DeployResult) string {

experimental/apps-mcp/lib/providers/io/format.go

@@ -1,19 +1,23 @@
 package io
 
-import "fmt"
+import (
+	"fmt"
+	"path/filepath"
+)
 
 // formatScaffoldResult formats a ScaffoldResult for display
 func formatScaffoldResult(result *ScaffoldResult) string {
 	return fmt.Sprintf(
 		"Successfully scaffolded %s template to %s\n\n"+
 			"Files copied: %d\n\n"+
 			"Template: %s\n\n"+
-			"%s",
+			"It is recomended to run the app in the background immediately after scaffolding using `npm install && npm run dev`. Then directly open http://localhost:8000 in the browser so the user can follow the progress.\n\n"+
+			"IMPORTANT: Make sure to read %s before proceeding with the project!!!\n\n",
 		result.TemplateName,
 		result.WorkDir,
 		result.FilesCopied,
 		result.TemplateName,
-		result.TemplateDescription,
+		filepath.Join(result.WorkDir, "CLAUDE.md"),
 	)
 }