- Read app instructions, schema/routes relevant to the change, and one neighboring implementation/test.
- For behavior changes, add a focused example in the app's existing test framework and run it to establish the current failure.
- Implement the smallest change that fits the app's conventions; keep queries, authorization, and side effects at their existing boundaries.
- Run the focused spec and the relevant project checks. Add documentation for public APIs when the app requires it.
Use the specialist card directly when the feature centers on a migration, authorization, background job, GraphQL, Hotwire, performance, API versioning, or an engine. Ask for a checkpoint only for production data, security/authorization, deployment, or irreversible changes.