TDD (Red-Green-Refactor)

Use this skill whenever you need reliable, incremental implementation with test-first development.

When to use

• Building new behavior where correctness matters
• Fixing bugs with a reproducible failing test
• Refactoring safely with behavior locked by tests
• Working in codebases where regression risk is high

Workflow

1. Red
   • Write or update a test that describes the intended behavior.
   • Run tests and verify the new/changed test fails for the right reason.