# CLAUDE.md — Django

## Commands
- Run: `uv run python manage.py runserver` · Tests: `uv run pytest` · Lint: `uv run ruff check . && uv run ruff format --check .`
- Migrations: `uv run python manage.py makemigrations <app>` then review the generated file before `migrate`.

## Conventions
- One Django app per bounded domain under `apps/`. Business logic in `services.py`/`selectors.py`, not in views or serializers.
- Fat models are fine for invariants; complex workflows go in services.
- DRF: explicit serializers with `fields = [...]` (never `"__all__"`), permission classes on every view.
- Query hygiene: `select_related`/`prefetch_related` for relations; check with `django-debug-toolbar` or `assertNumQueries` in tests.
- Settings split: `config/settings/{base,dev,prod}.py`; secrets from environment via `django-environ`.
- Never edit an applied migration; add a new one. Data migrations use `RunPython` with a reverse function.

## Don't
- Don't use raw SQL without parameters. Don't disable CSRF. Don't put logic in signals unless decoupling is required.