Purpose and inputs
Use TDD only when the user asked for it or the repository requires it. Follow the repo testing MDX and vitest-v4 (or the stack's test skill). Do not commit unless asked.
Steps
- Red: Write a failing test for the desired behavior. Use real APIs where the repo tests do; mock only at documented boundaries.
- Green: Write the smallest implementation that passes that test.
- Refactor: Improve structure while tests stay green. Follow lint and file-organization rules.
- Repeat for the next increment. Run the focused test file each cycle, then the affected suite.
Verification
- The new test failed before the implementation existed (or that fact is explained).
- The focused tests pass after green and after refactor.
- No unsolicited commit.
Handoff
Report the test files, the increment, and remaining uncovered behavior.