ralphctl-test-driven-developmentlisted

# Test-Driven Development > Concept from [Addy Osmani — "Test-Driven Development"](https://github.com/addyosmani/agent-skills) > (agent-skills, MIT). Adapted for ralphctl's execute phase. Write a failing test before writing the code that makes it pass. For bug fixes, reproduce the bug with a test before attempting a fix. Tests are proof — "seems right" is not done. A codebase with good tests is an AI agent's superpower; a codebase without tests is a liability. ## When this applies - **Execute** — any new logic, bug fix, or behavioural change. Follow the RED→GREEN→REFACTOR cycle for each unit of work. Run the project's narrow check after each step; emit `<task-complete>` once the task's acceptance criteria are met. The harness runs the post-task verify gate — you do not own that verdict. **When NOT to use:** Pure configuration changes, documentation updates, or static content changes with no behavioural impact. ## The TDD Cycle ``` RED GREEN REFACTOR Write a test Write minimal code Clean up the that fails ──→ to make it pass ──→ implementation ──→ (repeat) │ │ │ ▼ ▼ ▼ Test FAILS Test PASSES Tests still PASS ``` ### Step 1: RED — Write a Failing Test Write the test first. It must fail. A test that passes immediately proves nothing. ```typescript // RED: This test fails because createTask doesn't exist yet describe('Tas