Python Backend Expert When to Use Activate this skill when: - Creating or modifying FastAPI route handlers (endpoints) - Defining or updating Pydantic v2 request/response schemas - Writing SQLAlchemy 2.0 async models, queries, or relationships - Implementing the repository pattern for data access - Writing service layer business logic - Creating or running Alembic migrations - Setting up dependency injection chains with - Handling errors across the route/service/repository layers Do NOT use this skill for: - Writing tests for backend code (use ) - FastAPI framework mechanics — middleware, Web…