tdd

name	tdd
description	Test-driven development. Use when the user wants to build features or fix bugs test-first, mentions "red-green-refactor", or wants integration tests.

TDD Adapter

Thin tool adapter. Authoritative guide: Harness/TDD-GUIDE.md.

Invocation

• Claude Code: use /tdd or select the tdd skill.
• Codex CLI or IDE: use $tdd or /skills then choose tdd.

Load

1. Harness/ACCEPTANCE_PROTOCOL.md
2. Harness/HARNESS_BRIDGE.md
3. Harness/AGENT_ISOLATION.md
4. Harness/TDD-GUIDE.md
5. ECC stack-specific testing rules (for example typescript/testing.md, python/testing.md)
6. Current task PLAN.md

Rules

1. AC first: Tests are derived from PRD acceptance criteria and must reference AC IDs.
2. RED first: Write failing tests before ANY implementation code.
3. UI means real user path: Browser-visible behavior requires Playwright/CDP or documented real-browser clicks, typing, navigation, and visible assertions.
4. No syntax-only acceptance: Typecheck, lint, build, import tests, shallow renders, and snapshots cannot satisfy browser-visible ACs by themselves.
5. Network-aware: Frontend-backend ACs require URL, method, payload, response, and duplicate-request assertions when applicable.
6. GREEN minimal: Write only enough implementation to pass the AC-linked tests.
7. REFACTOR safe: Improve code while keeping all tests green.
8. Coverage gate: Meet the configured project coverage threshold before marking task complete.
9. AAA structure: Arrange -> Act -> Assert.
10. Role isolation: Test Writer must not reverse-engineer tests from implementation code. Implementer must not modify PRD, AC, UI contract, or API contract except through Change Request.
11. Evidence required: Record RED, GREEN, full-check output, and for UI flows screenshot/trace/video/log evidence plus an AC-by-AC result matrix.
12. WF-MAX: Acceptance/Test Writer wave completes before any Implementer wave starts.