Overview
test-driven-development is an open-source testing skill for Claude Code and compatible agents, published by addyosmani. Its author describes it as: “Drives development with tests using the red-green-refactor loop. Use when implementing any logic, fixing any bug, or changing any behavior. Use when you need to prove that code works, when a bug report arrives, or whe…”. The project has 98k stars on GitHub and is available under the MIT license. Add it to your setup with `/plugin marketplace add addyosmani/agent-skills`.
What test-driven-development does
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.
Best for
What’s inside
The SKILL.md for test-driven-development is organised into these sections:
- Overview
- When to Use
- Discover the Stack First
- The TDD Cycle
- Step 1: RED — Write a Failing Test
- Step 2: GREEN — Make It Pass
- Step 3: REFACTOR — Clean Up
- The Prove-It Pattern (Bug Fixes)
- The Test Pyramid
- Test Sizes (Resource Model)
- Decision Guide
- Writing Good Tests
Installation
Add test-driven-development to your agent with:
/plugin marketplace add addyosmani/agent-skillsReview a skill’s source before installing it — skills can instruct your agent to run commands. This command comes from the skill’s public repository, which is the source of truth for setup steps. New to skills? Read how to install Claude Code skills.
Supported agents
- Claude Code — ships a claude code plugin marketplace
- Codex — declared in the repository topics
- Cursor — declared in the repository topics
- Antigravity — declared in the repository topics
License
test-driven-development is published under the MIT license.
Strengths
- Clear MIT license — safe to read and adapt within its terms
- Ships in addyosmani/agent-skills, an established project with 97,992 GitHub stars
- Works with Claude Code, Codex, Cursor, Antigravity
- Actively maintained — repository updated in the last 30 days
- Its repository gained 16,916 GitHub stars over the last 52 days
Author
Topics
Alternatives to test-driven-development
Similar skills from other repositories:
Frequently asked questions
- What does test-driven-development do?
- Drives development with tests using the red-green-refactor loop. Use when implementing any logic, fixing any bug, or changing any behavior. Use when you need to prove that code works, when a bug report arrives, or when you're about to modify existing functionality.
- How do I install test-driven-development?
- Run /plugin marketplace add addyosmani/agent-skills in your agent, then reload your skills. Review the source at https://github.com/addyosmani/agent-skills before installing.
- Is test-driven-development free to use?
- Yes. test-driven-development is free and open source under the MIT license, so you can read, run, and adapt it within that license's terms.
- Which agents does test-driven-development work with?
- test-driven-development lists Claude Code, Codex, Cursor, and Antigravity — named in its SKILL.md, its plugin marketplace or its repository topics. Skills use the portable SKILL.md format, so other agents that read that format may load it too.
- Where does test-driven-development come from?
- test-driven-development ships inside addyosmani/agent-skills, a repository that contains 26 catalogued skills in total. The repository's 97,992 GitHub stars apply to that whole collection, not to this skill on its own.
