# Skill: GeoAI Backend Build

Use this skill when implementing FastAPI routers, services, schemas, domain logic, adapters or background-job entry points.

## Read first

- `docs/governance/GEOINTEL_CONSTITUTION.md`
- `docs/governance/ARCHITECTURE_INVARIANTS.md`
- `docs/SERVICE_ARCHITECTURE.md`
- `docs/API_CONTRACTS.md`
- active pass prompt

## Backend rules

- Keep routers thin.
- Put business logic in services.
- Put external integrations behind adapters.
- Use typed request/response schemas.
- Return stable error codes from the error catalog.
- Do not let AI/model code write directly to the database.
- Do not perform long processing synchronously when it belongs in jobs.

## Expected package pattern

```text
backend/app/
  api/
  core/
  db/
  models/
  schemas/
  services/
  workers/
  adapters/
```

## Implementation checklist

- [ ] Add/extend schemas.
- [ ] Add/extend service.
- [ ] Add/extend router.
- [ ] Add validation.
- [ ] Add tests or smoke checks.
- [ ] Update docs/log/changelog when behavior changes.

## Completion report fields

- Endpoints added/changed.
- Services added/changed.
- Validation rules added.
- Tests run.
- Contract deviations, if any.