This skill guides AI agents through the complete lifecycle of building ChatGPT Apps: 1) Fit Evaluation - Determine if a ChatGPT App is right for your product 2) Architecture Design - Plan MCP servers, tools, and widgets 3) Implementation - Build with Node.js, TypeScript, and React 4) Testing - Local development with ngrok, ChatGPT integration testing 5) Deployment - Production hosting and App Store submission