Tools

Test-driven development in vertical slices: agree on test seams with the user first, verify behavior only through public interfaces, and avoid listed anti-patterns such as implementation coupling and tautological tests. From Matt Pocock's skills collection.

Uses hooks to enforce test-driven development in Claude Code: blocks implementation without a failing test, prevents code beyond what tests require, and can use lint results to push refactoring. Needs Node.js 22+. Still maintained, but the author suggests its successor Probity for new projects.