Firebase Development
Overview
This skill system guides Firebase development using proven patterns from production projects. It routes to specialized sub-skills based on detected intent.
Sub-skills:
- •
firebase-development:project-setup- Initialize new Firebase projects - •
firebase-development:add-feature- Add functions/collections/endpoints - •
firebase-development:debug- Troubleshoot emulator and runtime issues - •
firebase-development:validate- Review Firebase code for security/patterns
When This Skill Applies
- •Starting new Firebase projects
- •Adding Cloud Functions or Firestore collections
- •Debugging emulator issues or rule violations
- •Reviewing Firebase code for security and patterns
- •Setting up multi-hosting configurations
- •Implementing authentication (API keys or Firebase Auth)
Routing Logic
Keywords by Sub-Skill
project-setup:
- •"new firebase project", "initialize firebase", "firebase init"
- •"set up firebase", "create firebase app", "start firebase project"
add-feature:
- •"add function", "create endpoint", "new tool", "add api"
- •"new collection", "add feature", "build", "implement"
debug:
- •"error", "not working", "debug", "emulator issue"
- •"rules failing", "permission denied", "troubleshoot", "deployment failed"
validate:
- •"review firebase", "check firebase", "validate", "audit firebase"
- •"look at firebase code", "security review"
Routing Process
- •Analyze Request: Check for routing keywords
- •Match Sub-Skill: Identify best match based on keyword density
- •Announce: "I'm using the firebase-development:[sub-skill] skill to [action]"
- •Route: Load and execute the sub-skill
- •Fallback: If ambiguous, use AskUserQuestion with 4 options
Fallback Example
If intent is unclear, ask:
code
Question: "What Firebase task are you working on?" Options: - "Project Setup" (Initialize new Firebase project) - "Add Feature" (Add functions, collections, endpoints) - "Debug Issue" (Troubleshoot errors or problems) - "Validate Code" (Review against patterns)
Reference Projects
Patterns are extracted from three production Firebase projects:
| Project | Path | Key Patterns |
|---|---|---|
| oneonone | /Users/dylanr/work/2389/oneonone | Express API, custom API keys, server-write-only |
| bot-socialmedia | /Users/dylanr/work/2389/bot-socialmedia-server | Domain-grouped functions, Firebase Auth + roles |
| meme-rodeo | /Users/dylanr/work/2389/meme-rodeo | Individual function files, entitlements |
Pattern Summaries
Multi-Hosting Setup
Three options based on needs:
| Option | When to Use | Key Feature |
|---|---|---|
site: based | Multiple independent URLs | Simple, no build coordination |
target: based | Need predeploy hooks | Build scripts run automatically |
| Single + rewrites | Smaller projects | All under one domain |
Details: See docs/examples/multi-hosting-setup.md
Authentication
| Pattern | When to Use | Example |
|---|---|---|
| Custom API keys | MCP tools, server-to-server | oneonone |
| Firebase Auth + roles | User-facing apps | bot-socialmedia |
| Hybrid | Both patterns needed | Web UI + API access |
Details: See docs/examples/api-key-authentication.md
Cloud Functions Architecture
| Pattern | When to Use | Structure |
|---|---|---|
| Express app | API with middleware, routing | app.post('/mcp', handler) |
| Domain-grouped | Feature-rich apps | posts.ts, journal.ts |
| Individual files | Maximum modularity | One function per file |
Details: See docs/examples/express-function-architecture.md
Security Model
| Model | When to Use | Complexity |
|---|---|---|
| Server-write-only | Light-write apps, high security | Simple rules |
| Client-write + validation | High-volume writes, real-time | Complex rules |
Strongly prefer server-write-only for light-write applications.
Details: See docs/examples/firestore-rules-patterns.md
Emulator-First Development
Always develop locally with emulators:
bash
firebase emulators:start # Access UI at http://127.0.0.1:4000
Key settings in firebase.json:
- •
singleProjectMode: true- Essential for emulators to work together - •
ui.enabled: true- Access debug UI
Details: See docs/examples/emulator-workflow.md
Modern Tooling Standards
All Firebase projects follow these standards:
| Tool | Purpose | Config File |
|---|---|---|
| TypeScript | Type safety | tsconfig.json |
| vitest | Testing | vitest.config.ts |
| biome | Linting + formatting | biome.json |
ABOUTME Comment Pattern
Every TypeScript file starts with 2-line ABOUTME comment:
typescript
// ABOUTME: Brief description of what this file does // ABOUTME: Second line with additional context
Testing Requirements
- •Unit tests: Test handlers/utilities in isolation
- •Integration tests: Test with emulators running
- •Both required for every feature
Common Gotchas
| Issue | Solution |
|---|---|
| Emulator ports in use | lsof -i :5001, kill process |
| Admin SDK vs Client SDK | Admin bypasses rules, client respects rules |
| Cold start delays | First call takes 5-10s, normal |
| Data persistence | Use Ctrl+C (not kill) to export data |
| CORS in functions | app.use(cors({ origin: true })) |
Summary
This orchestrator routes to specialized sub-skills:
- •Detects intent via keywords
- •Routes to appropriate sub-skill
- •Sub-skills use TodoWrite checklists
- •All reference shared patterns in
docs/examples/
Sub-Skills:
- •
firebase-development:project-setup- Initialize new projects - •
firebase-development:add-feature- Add functions/collections - •
firebase-development:debug- Troubleshoot issues - •
firebase-development:validate- Review code