python-error-handlingPython / FastAPI error contract — typed exception hierarchy, error-code and message catalogue, ONE handler mapping errors to RFC 9457 problem+json. Use when raising, adding or mapping any exception or error response. For request validation use `python-input-validation`.
python-input-validationPython input validation with pydantic v2 — Field constraints and validated types, model validators for cross-field rules, injectable rule objects, custom messages. Use when adding or changing any validation rule; never ad-hoc if/raise guards in routers or services.
python-persistencePython persistence with SQLAlchemy 2.0 (typed models, async sessions) and Alembic — repository per aggregate behind a Protocol, one unit-of-work boundary, optimistic locking. Use when adding storage, an entity, a migration or a query.