Test-Driven Development

by addyosmani

Test-Driven Development is a Quality skill for Claude Code, published by addyosmani in agent-skills.

86.7K stars9.3K forkson addyosmani/agent-skillsAdded 2026/08/13Repository updated 2026/08/11

View source on GitHub Download repo ZIP

agent-skillsantigravityclaude-codecodexcursorskills

Install in seconds

Install Test-Driven Development

Copy Test-Driven Development into your Claude Code skills folder. Run the command in your terminal, or review the source on GitHub before installing.

terminal

npx degit https://github.com/addyosmani/agent-skills/tree/main/skills/test-driven-development ~/.claude/skills/test-driven-development

Requires Node.js. Downloads this skill only — not the rest of the repository — into your Claude Code skills folder.

Without Node.js

git clone https://github.com/addyosmani/agent-skills.git

Clones the whole repository, then copy the skill’s own directory into your skills folder yourself.

In this catalog

Source file: skills/test-driven-development/SKILL.md in addyosmani/agent-skills
Installs to: ~/.claude/skills/test-driven-development
Collection: One of 24 skills cataloged from this repository
Category: Quality — 1354 skills

What Test-Driven Development does

Test-Driven Development guides writing a failing test before code to make it pass. Use it when implementing logic, fixing bugs, or modifying behavior to prove code works.

Test-Driven Development is cataloged under Quality on DirSkills. Test-Driven Development comes from a repository tagged agent-skills, antigravity, claude-code, codex and cursor.

Documentation

README

Excerpt

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 to Use

Implementing any new logic or behavior
Fixing any bug (the Prove-It Pattern)
Modifying existing functionality
Adding edge case handling
Any change that could break existing behavior

When NOT to use: Pure configuration changes, documentation updates, or static content changes that have no behavioral impact.

This is the opening of the README. Read the full README on GitHub.

Frequently asked about Test-Driven Development

What else does addyosmani publish alongside Test-Driven Development?
Test-Driven Development is one of 24 skills that DirSkills catalogs from addyosmani/agent-skills, the repository it ships in. Its siblings there include API and Interface Design, Agent Skill Discovery and Browser Testing. Each one is a separate skill with its own page in this directory, installs the same way Test-Driven Development does, and is maintained by addyosmani in that same repository. The rest of the collection is listed on the addyosmani/agent-skills page.
How does Test-Driven Development compare to other Quality skills?
Test-Driven Development ranks #26 by stars among the 1354 Quality skills in this catalog. The most-starred ones next to it are Benchmark, Benchmark Optimization Loop and API Design Patterns. DirSkills ranks by the star count of the repository each skill ships in, so that order reflects how popular those repositories are rather than any review of Test-Driven Development against them. Open each page to compare what they document and how they install.