What it is
tdd is a skill for test-driven development. Its SKILL.md emphasizes behavior through public interfaces, not implementation details, and warns against writing all tests before all implementation.
Why it is useful
It gives the agent a disciplined loop for feature work and bug fixes: write a failing behavior test, make it pass, then refactor while preserving the test signal.
Best uses
- New features where behavior can be described before implementation.
- Bug fixes where a regression test should exist before the fix.
- Refactors that need stable integration-style tests.
Notes
This skill is strongest when the repository already has a runnable test command. If not, pair it with a repo onboarding or run-and-verify skill.