python-fastapilisted

REQUIRED BACKGROUND: You MUST also follow the clean-code skill (`.claude/skills/clean-code/SKILL.md`). That skill covers universal principles (fail-closed errors, typed exceptions, self-documenting code, edge cases, error path tests). This skill adds FastAPI-specific patterns on top of those foundations. ## Pre-Code Checklist Before writing any backend Python code, verify: - [ ] Read `docs/engineering/fastapi-rules.md` — the canonical backend policy - [ ] If touching API routes: read `docs/playbooks/fastapi-service.md` - [ ] Search the repo with Grep/Glob for existing code before creating any new file - [ ] Confirm which Python version the project targets (≥ 3.11 recommended) ## 1. Project layout ``` src/backend/ ├── app/ │ ├── main.py # FastAPI() entry point │ ├── api/ # route modules, one file per resource │ │ └── v1/ │ ├── models/ # SQLAlchemy declarative models │ ├── schemas/ # Pydantic request/response schemas │ ├── services/ # business logic — pure, no Request/Response types │ ├── deps.py # dependency providers (DB session, current user) │ └── core/ │ ├── config.py # Pydantic Settings │ └── exceptions.py # typed domain errors └── tests/ ``` ## 2. Route pattern ```python @router.post("/items", response_model=ItemOut, status_code=201) async def create_item( payload: ItemIn, session: AsyncSession = Depends(get_session), current_user: User