tdd

name	tdd
description	Drive a change test-first with a strict red-green-refactor loop. Use when adding behavior to a repo that has (or should have) tests. Invoke manually with /tdd <what to build>.
disable-model-invocation	true

/tdd $ARGUMENTS

Build the behavior test-first. Discipline is the point: no production code without a failing test that demands it.

Loop

1. Understand the desired behavior and its acceptance criteria. Restate them briefly.
2. RED — write the smallest failing test that expresses the next slice of behavior. Run it. Confirm it fails for the right reason (not a typo/import error).
3. GREEN — write the minimum production code to make that test pass. Run it. Confirm green.
4. REFACTOR — clean up code and tests while staying green. Run again.
5. Repeat for the next slice until the behavior is complete.
6. Run the full relevant test suite once at the end.

Rules

• Never write production code ahead of a failing test that requires it.
• Never make a test pass by weakening its assertion.
• Match the repo's existing test framework and conventions (delegate discovery to explore or test-engineer if unfamiliar).
• Keep each red-green cycle small — minutes, not hours.