apps-MCP: template prompts decomposition (#4084)

## Changes
- decompose the only large structureless CLAUDE.md into bite-sized
dedicated sub-documents;
- hide the confusing long list of npm commands in favor of instructing
the agent to use encapsulated `validate`;
- create a way to regenerate types without `npm run dev` (as discussed
with @ditadi and @fjakobs, there will be an official way, thus my
implementation should be considered as temporal one).

## Why
- improve locality of instructions; 
- reduce amount of confusion points; 
- ensure maintainability of prompts; 

## Tests
Tested manually and via bulk generation

Author: arsenyinfo

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

@@ -5,29 +5,40 @@
      * Contains: available tools, CLI patterns, best practices.
      */ -}}
 
-## Available Tools
-- **databricks_discover**: Discover workspace resources and get workflow recommendations (call this first)
+## Databricks MCP Available Tools
+- **databricks_discover**: Discover workspace resources and get workflow recommendations
 - **databricks_configure_auth**: Switch workspace profile/host
 - **invoke_databricks_cli**: Execute any Databricks CLI command
 
 ## Workflow Best Practices
-- Use `databricks_discover` at the start of tasks to understand workspace context
-- Use `invoke_databricks_cli` for all Databricks CLI operations
-- For Databricks Asset Bundles: validate before deploying
+- Use `databricks_discover` at the beginning of your session to get context-aware recommendations
+- For operations affecting live environments, ask for confirmation
+- Always validate before deploying
 - When not sure about the user's intent, ask clarifying questions
-- Do NOT create summary files, reports, or README unless explicitly requested
 
 {{.WorkspaceInfo}}{{if .WarehouseName}}
 Default SQL Warehouse: {{.WarehouseName}} ({{.WarehouseID}}){{else}}
 Note: No SQL warehouse detected. SQL queries will require warehouse_id to be specified manually.{{end}}{{.ProfilesInfo}}
 
-IMPORTANT: Use invoke_databricks_cli for all commands below!
+## Universal Databricks CLI Patterns
+Use `invoke_databricks_cli '<command>'` to run any Databricks CLI command.
 
-## SQL Queries
-Execute SQL using the query tool:
-  invoke_databricks_cli 'experimental apps-mcp tools query "SELECT * FROM catalog.schema.table LIMIT 10"'
+### Project scaffolding
 
-## Exploring Resources
+For apps:
+
+invoke_databricks_cli 'experimental apps-mcp tools init-template --name my-app --description "My app description"'
+
+- App name must be ≤26 characters (dev- prefix adds 4 chars, max total 30)
+- Use lowercase letters, numbers, and hyphens only
+
+Other types of projects are not yet supported.
+
+### Custom SQL Queries
+
+invoke_databricks_cli 'experimental apps-mcp tools query "SELECT * FROM catalog.schema.table LIMIT 10"'
+
+### Exploring Resources
 Jobs:
   invoke_databricks_cli 'jobs list'
   invoke_databricks_cli 'jobs get <job_id>'
@@ -41,15 +52,5 @@ Unity Catalog:
   invoke_databricks_cli 'tables list <catalog> <schema>'
   invoke_databricks_cli 'experimental apps-mcp tools discover-schema TABLE1 TABLE2 TABLE3'
 
-⚠️ Use separate arguments for catalog/schema: 'tables list samples tpcds_sf1' (not dot notation)
-
-## Databricks Asset Bundles
-New project:
-  invoke_databricks_cli 'bundle init'
-  invoke_databricks_cli 'bundle validate'
-  invoke_databricks_cli 'bundle deploy --target dev'
-
-Existing project:
-  invoke_databricks_cli 'bundle validate'
-  invoke_databricks_cli 'bundle deploy --target <environment>'
-  invoke_databricks_cli 'bundle run <resource_name>'
+Use separate arguments for catalog/schema: 'tables list samples tpcds_sf1' (not dot notation).
+Dot notation is only supported in `experimental apps-mcp tools discover-schema` and `experimental apps-mcp tools query`.

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

@@ -7,23 +7,29 @@
 
 ## Databricks Apps Development
 
-### Building a New App
-1. Scaffold: invoke_databricks_cli 'experimental apps-mcp tools init-template --name my-app --description "My app description"'
-2. Read CLAUDE.md in the generated directory
-3. Navigate to project: cd <project_name>
-4. Run locally: npm install && npm run dev (opens http://localhost:8000)
-
 ### Validation
 ⚠️ Always validate before deploying:
   invoke_databricks_cli 'experimental apps-mcp tools validate ./'
 
+This is battle-tested to catch common issues before deployment. Prefer using this over manual checks (e.g. `npm run lint`), as it covers more ground specific to Databricks Apps.
+
 ### Deployment
 ⚠️ USER CONSENT REQUIRED: Only deploy with explicit user permission.
   invoke_databricks_cli 'experimental apps-mcp tools deploy'
 
-### App Naming
-- App name must be ≤26 characters (dev- prefix adds 4 chars, max total 30)
-- Use lowercase letters, numbers, and hyphens only
-
 ### View and Manage
   invoke_databricks_cli 'bundle summary'
+
+### Local Development vs Deployed Apps
+
+During development:
+- Start template-specific dev server (see project's CLAUDE.md for command and port)
+- Use localhost URL shown when dev server starts
+
+After deployment:
+- Get URL from: invoke_databricks_cli 'bundle summary'
+
+Decision tree:
+- "open the app" + not deployed → localhost
+- "open the app" + deployed → ask which environment
+- "localhost"/"local" → always localhost

experimental/apps-mcp/lib/validation/nodejs.go

@@ -32,6 +32,12 @@ func (v *ValidationNodeJs) Validate(ctx context.Context, workDir string) (*Valid
 			errorPrefix: "Failed to install dependencies",
 			displayName: "Install",
 		},
+		{
+			name:        "generate",
+			command:     "npm run typegen --if-present",
+			errorPrefix: "Failed to run npm typegen",
+			displayName: "Type generation",
+		},
 		{
 			name:        "build",
 			command:     "npm run build --if-present",

experimental/apps-mcp/templates/appkit/databricks_template_schema.json

@@ -25,5 +25,5 @@
         "order": 4
       }
     },
-    "success_message": "\nYour new project has been created in the '{{.project_name}}' directory!\nYOU MUST read {{.project_name}}/CLAUDE.md immediately. It is STRONGLY RECOMMENDED to immediately run `npm install`, run `npm run dev` in the background, and open http://localhost:8000 in your browser before making changes to the app."
+    "success_message": "\nYour new project has been created in the '{{.project_name}}' directory!\nYOU MUST read {{.project_name}}/CLAUDE.md immediately."
   }