tdd

Enforce a RED-GREEN-REFACTOR cycle for production code implementation.

25|7|Updated Mar 16, 2026
One-click install
npx skills add https://github.com/xoai/sage --skill tdd-xoai
Or copy as Structured Prompt for Agent
Please help me install this Agent Skill.
Skill: tdd
Source: https://github.com/xoai/sage/tree/main/core/capabilities/execution/tdd
Command: npx skills add https://github.com/xoai/sage --skill tdd-xoai

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill includes references (resource) components.

What problem does it solve?

This Skill enforces a disciplined approach to software development by ensuring that all production code is written only after a corresponding test has been created and observed failing, preventing bugs and improving code reliability.

Core Features & Use Cases

  • Mandatory Test-Driven Development: Guarantees that code is written to pass a pre-defined, failing test.
  • Iterative Development Cycle: Guides the developer through the RED (write failing test) -> GREEN (write minimal code) -> REFACTOR (clean up) cycle.
  • Use Case: When implementing any new feature, fixing a bug, or refactoring existing code, this Skill ensures that a test is written first, verifying the expected behavior and preventing regressions.

Quick Start

Use the tdd skill to write a test for the new user authentication feature.

Frequently Asked Questions about tdd

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
What is test-driven development and how does it improve code quality?

Test-driven development mandates writing a failing test before implementation, then writing minimal code to pass it, and refactoring. This strict RED-GREEN-REFACTOR cycle ensures verifiable behavior and prevents bugs.

How do I implement a new feature using the RED-GREEN-REFACTOR cycle?

To implement a feature, first write a failing test for the expected behavior, then write the minimal production code required to pass that test, and finally refactor the code for quality while ensuring the test still passes.

When should I write tests first during software development?

You should write tests first when implementing any new feature, fixing a bug, or refactoring existing code. This approach verifies expected behavior immediately and prevents regressions throughout the development lifecycle.

Does test-driven development work for fixing bugs and refactoring existing code?

Yes, test-driven development works for fixing bugs and refactoring by ensuring a test is written first to verify the expected behavior. This discipline prevents regressions and maintains code reliability during modifications.

What are the limitations of enforcing strict test-driven development?

Enforcing strict test-driven development requires writing a failing test before any production code, which may slow down initial implementation speed. However, this discipline is mandatory to ensure verifiable behavior and prevent future regressions.