What problem does it solve? Code written before tests often ships untested, and tests written after implementation pass immediately without proving they can catch bugs. This Skill enforces a strict test-first discipline so every behavior change is verified by a failing test before any production code exists. ## Core Features & Use Cases - Red-Green-Refactor Enforcement: Guides the full cycle of writing a failing test, verifying it fails for the right reason, writing minimal code to pass, and refactoring while staying green. - Rationalization Detection: Lists common excuses for skipping TDD ("too simple to test", "I'll test after") with concrete rebuttals, plus red flags that signal you should delete code and start over. - Test Quality Rules: A companion reference defines how to write honest tests — naming the break each test catches, asserting real behavior instead of mocks, and running a mutation check. - Use Case: When fixing a bug where empty emails are accepted, write a failing test asserting the rejection error first, watch it fail, then implement the minimal validation to make it pass. ## Quick Start Ask the agent to implement a new feature or bugfix using strict test-driven development with a failing test written first.
