databricks-apps

name	databricks-apps
description	Build apps on Databricks Apps platform. Use when asked to create dashboards, data apps, analytics tools, or visualizations. Invoke BEFORE starting implementation.
compatibility	Requires databricks CLI (>= v0.294.0)
metadata	{"version":"0.1.1"}
parent	databricks-core

Databricks Apps Development

FIRST: Use the parent databricks-core skill for CLI basics, authentication, and profile selection.

Build apps that deploy to Databricks Apps platform.

Required Reading by Phase

Phase	READ BEFORE proceeding
Scaffolding	Parent databricks-core skill (auth, warehouse discovery); run databricks apps manifest and use its plugins/resources to build databricks apps init with --features and --set (see AppKit section below)
Writing SQL queries	SQL Queries Guide
Writing UI components	Frontend Guide
Using useAnalyticsQuery	AppKit SDK
Adding API endpoints	tRPC Guide
Using Lakebase (OLTP database)	Lakebase Guide
Typed data contracts (proto-first design)	Proto-First Guide and Plugin Contracts
Platform rules (permissions, deployment, limits)	Platform Guide — READ for ALL apps including AppKit
Non-AppKit app (Streamlit, FastAPI, Flask, Gradio, Next.js, etc.)	Other Frameworks

Generic Guidelines

• App name: ≤26 characters, lowercase letters/numbers/hyphens only (no underscores). dev- prefix adds 4 chars, max 30 total.
• Validation: databricks apps validate --profile <PROFILE> before deploying.
• Smoke tests (AppKit only): ALWAYS update tests/smoke.spec.ts selectors BEFORE running validation. Default template checks for "Minimal Databricks App" heading and "hello world" text — these WILL fail in your custom app. See testing guide.
• Authentication: covered by parent databricks-core skill.

Project Structure (after databricks apps init --features analytics)

• client/src/App.tsx — main React component (start here)
• config/queries/*.sql — SQL query files (queryKey = filename without .sql)
• server/server.ts — backend entry (tRPC routers)
• tests/smoke.spec.ts — smoke test (⚠️ MUST UPDATE selectors for your app)
• client/src/appKitTypes.d.ts — auto-generated types (npm run typegen)

Project Structure (after databricks apps init --features lakebase)

• server/server.ts — backend with Lakebase pool + tRPC routes
• client/src/App.tsx — React frontend
• app.yaml — manifest with database resource declaration
• package.json — includes @databricks/lakebase dependency
• Note: No config/queries/ — Lakebase apps use pool.query() in tRPC, not SQL files

Data Discovery

Before writing any SQL, use the parent databricks-core skill for data exploration — search information_schema by keyword, then batch discover-schema for the tables you need. Do NOT skip this step.

Development Workflow (FOLLOW THIS ORDER)

Analytics apps (--features analytics):

1. Create SQL files in config/queries/
2. Run npm run typegen — verify all queries show ✓
3. Read client/src/appKitTypes.d.ts to see generated types
4. THEN write App.tsx using the generated types
5. Update tests/smoke.spec.ts selectors
6. Run databricks apps validate --profile <PROFILE>

DO NOT write UI code before running typegen — types won't exist and you'll waste time on compilation errors.

Lakebase apps (--features lakebase): No SQL files or typegen. See Lakebase Guide for the tRPC pattern: initialize schema at startup, write procedures in server/server.ts, then build the React frontend.

When to Use What

• Read analytics data → display in chart/table: Use visualization components with queryKey prop
• Read analytics data → custom display (KPIs, cards): Use useAnalyticsQuery hook
• Read analytics data → need computation before display: Still use useAnalyticsQuery, transform client-side
• Read/write persistent data (users, orders, CRUD state): Use Lakebase pool via tRPC — see Lakebase Guide
• Call ML model endpoint: Use tRPC
• ⚠️ NEVER use tRPC to run SELECT queries against the warehouse — always use SQL files in config/queries/
• ⚠️ NEVER use useAnalyticsQuery for Lakebase data — it queries the SQL warehouse only

Frameworks

AppKit (Recommended)

TypeScript/React framework with type-safe SQL queries and built-in components.

Official Documentation — the source of truth for all API details:

npx @databricks/appkit docs                              # ← ALWAYS start here to see available pages
npx @databricks/appkit docs <query>                      # view a section by name or doc path
npx @databricks/appkit docs --full                       # full index with all API entries
npx @databricks/appkit docs "appkit-ui API reference"    # example: section by name
npx @databricks/appkit docs ./docs/plugins/analytics.md  # example: specific doc file

DO NOT guess doc paths. Run without args first, pick from the index. The <query> argument accepts both section names (from the index) and file paths. Docs are the authority on component props, hook signatures, and server APIs — skill files only cover anti-patterns and gotchas.

App Manifest and Scaffolding

Agent workflow for scaffolding: get the manifest first, then build the init command.

1. Get the manifest (JSON schema describing plugins and their resources):

   databricks apps manifest --profile <PROFILE>
   # See plugins available in a specific AppKit version:
   databricks apps manifest --version <VERSION> --profile <PROFILE>
   # Custom template:
   databricks apps manifest --template <GIT_URL> --profile <PROFILE>
   

   The output defines:

   • Plugins: each has a key (plugin ID for --features), plus requiredByTemplate, and resources.
   • requiredByTemplate: If true, that plugin is mandatory for this template — do not add it to --features (it is included automatically); you must still supply all of its required resources via --set. If false or absent, the plugin is optional — add it to --features only when the user's prompt indicates they want that capability (e.g. analytics/SQL), and then supply its required resources via --set.
   • Resources: Each plugin has resources.required and resources.optional (arrays). Each item has resourceKey and fields (object: field name → description/env). Use --set <plugin>.<resourceKey>.<field>=<value> for each required resource field of every plugin you include.

2. Scaffold (DO NOT use npx; use the CLI only):

   databricks apps init --name <NAME> --features <plugin1>,<plugin2> \
     --set <plugin1>.<resourceKey>.<field>=<value> \
     --set <plugin2>.<resourceKey>.<field>=<value> \
     --description "<DESC>" --run none --profile <PROFILE>
   # --run none: skip auto-run after scaffolding (review code first)
   # With custom template:
   databricks apps init --template <GIT_URL> --name <NAME> --features ... --set ... --profile <PROFILE>
   

   Optionally use --version <VERSION> to target a specific AppKit version.

   • Required: --name, --profile. Name: ≤26 chars, lowercase letters/numbers/hyphens only. Use --features only for optional plugins the user wants (plugins with requiredByTemplate: false or absent); mandatory plugins must not be listed in --features.
   • Resources: Pass --set for every required resource (each field in resources.required) for (1) all plugins with requiredByTemplate: true, and (2) any optional plugins you added to --features. Add --set for resources.optional only when the user requests them.
   • Discovery: Use the parent databricks-core skill to resolve IDs (e.g. warehouse: databricks warehouses list --profile <PROFILE> or databricks experimental aitools tools get-default-warehouse --profile <PROFILE>).

DO NOT guess plugin names, resource keys, or property names — always derive them from databricks apps manifest output. Example: if the manifest shows plugin analytics with a required resource resourceKey: "sql-warehouse" and fields: { "id": ... }, include --set analytics.sql-warehouse.id=<ID>.

READ AppKit Overview for project structure, workflow, and pre-implementation checklist.

Common Scaffolding Mistakes

# ❌ WRONG: name is NOT a positional argument
databricks apps init --features analytics my-app-name
# → "unknown command" error

# ✅ CORRECT: use --name flag
databricks apps init --name my-app-name --features analytics --set "..." --profile <PROFILE>

Directory Naming

databricks apps init creates directories in kebab-case matching the app name. App names must be lowercase with hyphens only (≤26 chars).

Other Frameworks (Streamlit, FastAPI, Flask, Gradio, Dash, Next.js, etc.)

Databricks Apps supports any framework that runs as an HTTP server. LLMs already know these frameworks — the challenge is Databricks platform integration.

READ Other Frameworks Guide BEFORE building any non-AppKit app. It covers port/host configuration, app.yaml and databricks.yml setup, dependency management, networking, and framework-specific gotchas.