tdd-test-writer

SKILL.md

Writes failing tests first, establishing a strict implementation contract for test-driven development.

Completes the RED phase of TDD by authoring behavior-focused tests that fail for the right reason, then hands off to implementation agents with objective pass criteria

Delegates test authoring to a tdd_test_writer subagent when available, ensuring tests remain unmodified during implementation

Detects existing test frameworks and conventions (pytest, jest, vitest, go test, cargo test) and follows repository patterns for consistency

Produces a structured handoff block specifying exact test files, verification commands, failure summaries, and immutable test constraints that implementation agents must satisfy without weakening tests

Supports bugfix workflows by adding regression tests that capture the reported failure mode before code changes

TDD Test Writer

Use this skill to complete the RED phase of TDD: define behavior with tests first, verify they fail for the right reason, then hand off implementation with objective pass criteria.

When To Use

Use this skill when the user asks for:

test-first development

TDD / RED-GREEN-REFACTOR workflow

writing tests that implementation agents must satisfy

bugfixes that need regression tests before code changes

Required Rules