fullstack-engineer

# Fullstack Engineer ## When To Use Use this skill when you need to: - Implement an approved feature from a product brief - Translate acceptance criteria into code changes - Decide where UI, API, and domain logic should live - Keep delivery synchronized with QA expectations ## Required Inputs Read these first: - `docs/product/<feature>/PRD.md` - `docs/product/<feature>/IMPLEMENTATION.md` - `docs/product/<feature>/QA.md` Then apply the relevant repository skills: - `project-layout` - `integration-standards` - `integration-testing` - `firebase-integration` when Firebase auth or Firestore changes - `gemini-question-generation` when quiz generation behavior changes ## Default Workflow 1. Map each acceptance criterion to the smallest code path that satisfies it. 2. Keep route handlers thin: auth, validation, orchestration, response mapping. 3. Put reusable business logic in `lib/<domain>/`. 4. Keep dashboard and component changes consistent with existing UI patterns. 5. Add or update integration coverage for user-visible server behavior. 6. Reconcile implementation notes back into the feature packet when scope changes. ## Repo-Specific Guidance - App Router pages and route handlers live under `app/`. - Reusable UI belongs in `components/`. - Shared quiz logic belongs in `lib/quiz/`. - Integration tests belong in `tests/integration/`. - Prefer `@/*` imports and preserve current status-code semantics. ## Delivery Checklist - [ ] Files are placed according to repository layout. - [ ] Protected routes authenticate before expensive work. - [ ] Validation and rate limits are applied where needed. - [ ] Shared logic is not duplicated across route files. - [ ] Integration tests cover the new behavior. - [ ] Lint and targeted tests pass before handoff. ## Handoff To QA Report: - What changed for users - What changed in API/data shape - What edge cases were intentionally covered - Any residual risks or deferred follow-ups ## Anti-Patterns Do not: - Bury business logic inside large route handlers. - Skip tests for new API behavior. - Drift from the approved feature packet without updating docs. - Pull Gemini into a feature unless the requirement actually needs it.