firebase-development-add-featurelisted

# Firebase Add Feature ## Overview This sub-skill guides adding new features to existing Firebase projects using TDD. It handles Cloud Functions, Firestore collections, and API endpoints. **Key principles:** - Write tests FIRST (TDD requirement) - Use `{success, message, data?}` response pattern - Every file starts with ABOUTME comments - Verify with emulators before claiming done ## When This Sub-Skill Applies - Adding a new Cloud Function - Creating a new Firestore collection with rules - Adding an API endpoint to Express app - User says: "add function", "create endpoint", "new collection", "implement" **Do not use for:** - Initial project setup → `firebase-development:project-setup` - Debugging → `firebase-development:debug` - Code review → `firebase-development:validate` ## TodoWrite Workflow Create checklist with these 12 steps: ### Step 1: Identify Feature Type Determine what's being added: - **HTTP Endpoint** - API route (GET/POST/etc.) - **Firestore Trigger** - Runs on document changes - **Scheduled Function** - Cron job - **Callable Function** - Client SDK calls - **New Collection** - Firestore collection with rules ### Step 2: Check Existing Architecture Examine the project to understand patterns: ```bash ls -la functions/src/ grep -r "onRequest" functions/src/ grep "express" functions/package.json ``` **Determine:** Architecture style, auth method, security model. **Reference:** `docs/examples/express-function-architecture.md` ### Step 3: Write Failin