---

name: aid-development description: AID Phase 4 - Development phase. Use for implementing features, TDD practices, code reviews, transitioning from planning to QA.

Development Phase Skill

MANDATORY: QA Gate After EVERY Task

Iron Rule: Task complete → Spawn QA → Wait for result → PASS? Next task : Fix

CopyTask(
  subagent_type="general-purpose",
  prompt="You are a QA Validator. Read .aid/qa/{TASK-ID}.yaml and review modified files. Return JSON with verdict: PASS or FAIL.",
  description="QA validation for {TASK-ID}"
)

• PASS → Proceed to next task
• FAIL → Fix issues in action_required, spawn QA again

---

Phase Overview

Purpose: Implement solution with quality built-in through TDD.

Entry: Tech spec completed, architecture defined Exit: All features implemented, tests passing, code reviewed

Deliverables

1. Production Code - Clean, documented, follows standards
2. Test Suite - Unit, integration, E2E, >80% coverage
3. Documentation - Code docs, API docs, README updates

TDD Workflow

RED (failing test) → GREEN (make pass) → REFACTOR (clean up) → REPEAT

Common Pitfalls

Code Quality

Required:

• Single responsibility functions
• DRY - no copy-paste
• Type hints on public functions
• Meaningful names
• Error handling

Forbidden:

• No any types
• No TODO/FIXME
• No commented-out code
• No test-specific branching

Documentation Standards

File-Level:

Copy/**
 * @file UserService.ts
 * @description Purpose
 * @related ./UserRepository.ts
 */

Function:

Copy/**
 * Creates user account.
 * @param data - User input
 * @returns Created user
 * @throws {ValidationError} If email invalid
 */

QA Gate Enforcement

Per-Task Flow

1. Read Task + QA Criteria (.aid/qa/{task-id}.yaml)
2. Implement Task (TDD)
3. Signal Complete (TodoWrite)
4. SPAWN QA SUB-AGENT (mandatory)
5. Process QA Report → PASS: next task, FAIL: fix & retry

QA Criteria Location

.aid/qa/{task-id}.yaml:

Copycriteria:
  must_achieve:    # What code MUST do
  must_not:        # What code must NEVER do
  not_included:    # Scope boundaries
  best_practices:  # Quality standards

QA Sub-Agent Context (Isolated)

Sees: Epic goal, Story value, Acceptance criteria, Changed files Does NOT see: Tech Spec, Architecture, Developer notes

QA Gate Rules

When QA Fails

1. Read report at .aid/qa/{task-id}-review-{N}.json
2. Fix each issue in action_required
3. Re-spawn QA
4. Repeat until PASS or max cycles

---

Phase Gate Checklist

• All features per spec
• All tests passing
• Edge cases tested
• Code reviewed
• No test-specific logic in prod
• Documentation updated
• All tasks passed QA gate

Role Guidance

Handoff to QA

• Complete, tested code
• Test results + coverage
• Known issues (if any)
• Deployment instructions