What problem does it solve? Teams practicing acceptance test-driven development often write tests after implementation, losing the design feedback that failing-first tests provide. This Skill generates red-phase acceptance test scaffolds before any code exists, mapping story acceptance criteria to E2E, API, and component tests with fixtures, factories, and an implementation checklist for developers. ## Core Features & Use Cases - Red-Phase Scaffold Generation: Creates Playwright or Cypress test files marked with test.skip() across E2E, API, and component levels, each mapped to acceptance criteria and P0-P3 priorities. - Test Infrastructure: Generates faker-based data factories, auto-cleanup fixtures, mock requirements, and required data-testid attribute lists for the DEV team. - 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 with five acceptance criteria, produce skipped E2E and API test scaffolds, factories, fixtures, and an ATDD checklist that developers activate one test at a time through red-green-refactor. ## 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 test scaffolds.