google-apis-integration {Backend} (v1.0)

"Firebase Functions are your backend. Design them like microservices, deploy them like magic."

Purpose

Google Sheets API v4, Docs API v1, Calendar API v3, Maps JS API, YouTube Data API v3 integration patterns. [EXPLICIT] When to use: Backend development within Firebase/Google ecosystem.

Core Principles

1. Law of Functions: Each Cloud Function does ONE thing. Single responsibility. [EXPLICIT]
2. Law of Cold Start: Minimize dependencies. Use lazy imports. Set min instances for critical functions. [EXPLICIT]
3. Law of Security: Every HTTP function verifies Firebase ID tokens. No public endpoints without auth. [EXPLICIT]

Core Process

Phase 1: Design

1. Map requirements to Cloud Functions triggers (HTTP, Firestore, Auth, Storage, scheduled). [EXPLICIT]
2. Define input/output contracts for each function. [EXPLICIT]
3. Design error handling and retry strategy. [EXPLICIT]

Phase 2: Implement

1. Create function with proper trigger type. [EXPLICIT]
2. Add auth middleware for HTTP functions. [EXPLICIT]
3. Implement business logic with error handling. [EXPLICIT]
4. Add Cloud Logging for observability. [EXPLICIT]

Phase 3: Test + Deploy

1. Test with Firebase Emulator Suite. [EXPLICIT]
2. Deploy with firebase deploy --only functions. [EXPLICIT]
3. Verify in Firebase Console. [EXPLICIT]

3. Inputs / Outputs

Input	Type	Required	Description
Requirements	Text/Spec	Yes	What the function does
Output	Type	Description
--------	------	-------------
Cloud Function code	TypeScript	Deployable function

Validation Gate

• Single responsibility per function
• Auth middleware on HTTP endpoints
• Error handling with Cloud Logging
• Emulator tests pass
• No AWS/Azure services (R-002)

5. Self-Correction Triggers

[!WARNING] IF function has no auth middleware THEN add verifyIdToken check. IF function imports 10+ dependencies THEN split or lazy-load to reduce cold start.

Usage

Example invocations:

• "/google-apis-integration" — Run the full google apis integration workflow
• "google apis integration on this project" — Apply to current context

Assumptions & Limits

• Assumes access to project artifacts (code, docs, configs) [EXPLICIT]
• Requires English-language output unless otherwise specified [EXPLICIT]
• Does not replace domain expert judgment for final decisions [EXPLICIT]

Edge Cases

Scenario	Handling
Empty or minimal input	Request clarification before proceeding
Conflicting requirements	Flag conflicts explicitly, propose resolution
Out-of-scope request	Redirect to appropriate skill or escalate