What problem does it solve? Teams practicing TDD often skip writing acceptance tests before implementation, losing the red-green-refactor discipline. This Skill generates failing (red-phase) acceptance test scaffolds from a story's acceptance criteria before any code exists, complete with fixtures, data factories, and a developer implementation checklist. ## Core Features & Use Cases - Red-Phase Test Generation: Creates E2E, API, and component test scaffolds marked with test.skip() that fail only when activated, mapped to acceptance criteria with P0-P3 priorities. - Test Infrastructure: Produces faker-based data factories, Playwright fixtures with auto-cleanup, mock requirements, and required data-testid attribute lists. - Tri-Modal Workflow: Supports Create, Resume, Validate, and Edit modes with step-file architecture, progress tracking frontmatter, and a validation checklist. - Use Case: Given a user story for guest checkout, generate Playwright E2E and API scaffolds plus an ATDD checklist that the dev team activates one test at a time during implementation. ## Quick Start Ask the agent to write acceptance tests for a story file, for example: run ATDD for docs/stories/2-4-guest-checkout.md and generate the red-phase scaffolds.