tdd

name	tdd
description	Test-Driven Development enforcement skill - write tests first, always

TDD Mode

[TDD MODE ACTIVATED]

The Iron Law

NO PRODUCTION CODE WITHOUT A FAILING TEST FIRST

Write code before test? DELETE IT. Start over. No exceptions.

Red-Green-Refactor Cycle

1. RED: Write Failing Test

• Write test for the NEXT piece of functionality
• Run test - MUST FAIL
• If it passes, your test is wrong

2. GREEN: Minimal Implementation

• Write ONLY enough code to pass the test
• No extras. No "while I'm here."
• Run test - MUST PASS

3. REFACTOR: Clean Up

• Improve code quality
• Run tests after EVERY change
• Must stay green

4. REPEAT

• Next failing test
• Continue cycle

Enforcement Rules

If You See	Action
Code written before test	STOP. Delete code. Write test first.
Test passes on first run	Test is wrong. Fix it to fail first.
Multiple features in one cycle	STOP. One test, one feature.
Skipping refactor	Go back. Clean up before next feature.

Commands

Before each implementation:

# Run the project's test command - should have ONE new failure

After implementation:

# Run the project's test command - new test should pass, all others still pass

Output Format

When guiding TDD:

## TDD Cycle: [Feature Name]

### RED Phase
Test: [test code]
Expected failure: [what error you expect]
Actual: [run result showing failure]

### GREEN Phase
Implementation: [minimal code]
Result: [run result showing pass]

### REFACTOR Phase
Changes: [what was cleaned up]
Result: [tests still pass]

External Model Consultation (Preferred)

The tdd-guide agent SHOULD consult Codex for test strategy validation.

Protocol

1. Form your OWN test strategy FIRST - Design tests independently
2. Consult for validation - Cross-check test coverage strategy
3. Critically evaluate - Never blindly adopt external suggestions
4. Graceful fallback - Never block if tools unavailable

When to Consult

• Complex domain logic requiring comprehensive test coverage
• Edge case identification for critical paths
• Test architecture for large features
• Unfamiliar testing patterns

When to Skip

• Simple unit tests
• Well-understood testing patterns
• Time-critical TDD cycles
• Small, isolated functionality

Tool Usage

Before first MCP tool use, call ToolSearch("mcp") to discover deferred MCP tools. Use mcp__x__ask_codex with agent_role: "tdd-guide". If ToolSearch finds no MCP tools, fall back to the test-engineer agent.

Remember: The discipline IS the value. Shortcuts destroy the benefit.