---
description: "Backend Python development rules for FastAPI, SQLAlchemy 2.x, async patterns, and Alembic migrations."
globs: "core/**/*.py,edgekit/**/*.py"
alwaysApply: false
---

# Backend Python Rules

These rules apply when working on backend Python code in `core/` and `edgekit/`.

## Technology Stack

- **Framework**: FastAPI (Python 3.11+)
- **ORM**: SQLAlchemy 2.x with async session patterns
- **Migrations**: Alembic
- **Database**: PostgreSQL 16
- **Authentication**: JWT (custom implementation)

## Coding Standards

- Use `ruff` for linting and formatting (config in `pyproject.toml`)
- Always run `ruff check .` before committing
- Use `mypy` for type checking
- Python 3.11+ features are allowed (StrEnum, etc.)
- Use async/await patterns for all FastAPI endpoints

## Database Operations

**CRITICAL**: All database operations MUST use RLS context helpers.

```python
# User operations
async with with_user_context(session, user_id) as ctx:
    result = await ctx.execute(select(Model).where(Model.user_id == user_id))

# Admin operations
async with with_admin_context(session, user_id) as ctx:
    result = await ctx.execute(select(Model))

# System/background operations
async with with_system_context(session, "source_name") as ctx:
    result = await ctx.execute(insert(Model).values(data))
```

Never use direct session calls without RLS context wrappers.

## Migration Workflow

```bash
alembic revision --autogenerate -m "description"  # Create migration
alembic upgrade head                               # Apply locally
# Review the generated migration file before committing
git add alembic/versions/
git commit -m "feat(db): add migration description [{{TICKET_PREFIX}}-XXX]"
```

Rules:
- Always create proper Alembic migrations (never skip)
- Review auto-generated migrations for correctness
- Add RLS policies for any new tables
- Schema changes require System Architect approval

## FastAPI Patterns

- Use dependency injection for database sessions
- Use Pydantic v2 models for request/response validation
- Use proper HTTP status codes
- Include OpenAPI documentation (FastAPI generates this)
- Use structured logging

## Testing

- Use `pytest` with async support (`pytest-asyncio`)
- Run `pytest tests/` before committing
- Integration tests go in `tests/integration/`
- E2E tests go in `tests/e2e/`

## Key References

- See `patterns_library/api/` for API route patterns
- See `docs/database/DATA_DICTIONARY.md` for schema reference
- See `docs/database/RLS_IMPLEMENTATION_GUIDE.md` for RLS patterns
- See `CONTRIBUTING.md` for full workflow details