mir-backend-python-fastapi

Make It Right (FastAPI module). FastAPI + Async SQLAlchemy 2.0 + Postgres + Alembic + Redis specific reliability augmentation. Use alongside the mir-backend skill when the target stack is FastAPI — it carries the mechanical footguns that the framework-agnostic skill deliberately omits: async session lifecycle and scope, Pydantic v2 validation boundaries, Depends()-based auth and authorization, BackgroundTasks vs a real queue, async N+1 with selectinload, greenlet/sync-driver-in-async traps, Alembic migration safety on populated tables, and Redis idempotency/locking patterns. TRIGGER only when the Python backend stack is FastAPI — building, reviewing, or debugging a FastAPI endpoint, dependency, SQLAlchemy session, or Alembic migration. Always loads TOGETHER WITH mir-backend (the gates) and mir-backend-python (CPython runtime concerns: GIL, async/sync, fork-safety, cold start); this module only adds FastAPI/SQLAlchemy library mechanics. SKIP for Django, Flask, or any non-FastAPI stack (those get their own mir-backend-python-<framework> module), and for non-Python runtimes.