What problem does it solve? AI-assisted coding often produces large, unverified code blocks that are hard to trust and debug. This Skill enforces a disciplined Test-Driven Development cycle so every feature, bug fix, or migration is backed by a failing test first, a minimal passing implementation, and a safe refactoring step. ## Core Features & Use Cases - Three-Phase Cycle: Guides the AI through Red (write one failing test), Green (write the minimal code to pass), and Refactor (clean up while tests stay green). - Incremental Discipline: Forbids writing multiple tests at once, requiring a strict one-test-at-a-time loop for every sub-feature. - Integrity Rules: Prevents modifying existing tests just to make weak implementations pass, using TypeScript typing and assertions as backpressure against low-quality code. - Use Case: When adding a new utility function in a Vitest-based TypeScript project, the Skill ensures the AI writes a failing test first, proves the failure, implements the minimal fix, and only then refactors with type safety. ## Quick Start Use the TDD skill to implement the new checkout discount function in TypeScript, writing one failing Vitest test at a time before each implementation step.
