Firebase Project Setup

Overview

This sub-skill guides initializing a new Firebase project with proven architecture patterns. It handles Firebase CLI setup, architecture decisions, emulator configuration, and initial project structure.

Key principles:

• Use TypeScript for all functions
• Configure emulators from the start
• Choose architecture patterns early (hosting, auth, functions, security)
• Set up testing infrastructure immediately

When This Sub-Skill Applies

• Starting a brand new Firebase project
• Setting up Firebase for the first time in a repository
• User says: "new firebase project", "initialize firebase", "firebase init", "set up firebase"

Do not use for:

• Adding features to existing projects → firebase-development:add-feature
• Debugging existing setup → firebase-development:debug

Architecture Decisions

Use AskUserQuestion to gather these four decisions upfront:

1. Hosting Configuration

• Single Site - One hosting site, simple project
• Multiple Sites (site:) - Multiple independent URLs
• Multiple with Builds (target:) - Multiple sites with predeploy hooks

Reference: docs/examples/multi-hosting-setup.md

2. Authentication Approach

• API Keys - MCP tools, server-to-server, programmatic access
• Firebase Auth - User-facing app with login UI
• Both - Firebase Auth for web + API keys for tools

Reference: docs/examples/api-key-authentication.md

3. Functions Architecture

• Express API - Many related endpoints, need middleware, RESTful routing
• Domain Grouped - Feature-rich app with distinct areas (posts, admin)
• Individual Files - Independent functions, maximum modularity

Reference: docs/examples/express-function-architecture.md

4. Security Model

• Server-Write-Only (Preferred) - Cloud Functions handle all writes
• Client-Write - High-volume writes, need fastest UX, complex rules

Reference: docs/examples/firestore-rules-patterns.md

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