skill CX Codex

tdd · brianlovin — Claude Code skill: what it does, how to install

Q: How to install tdd in Claude Code?

Run `npx skills add brianlovin/agent-config --skill tdd -a claude-code` in your terminal.

Guides agents through a disciplined red-green-refactor loop. It builds features one vertical slice at a time and tests public behavior over implementation details.

Install into Claude Code · Skills CLI (Vercel) All methods and platforms ↓

npx skills add brianlovin/agent-config --skill tdd -a claude-code

Open on GitHub

What tdd does

This skill enforces a strict test-driven workflow. Instead of generating dozens of tests upfront, the agent plans the public interface with you, identifies critical behaviors, and writes a single failing test. It then writes just enough code to make that test pass before moving on.

The workflow explicitly blocks horizontal slicing, where one writes all tests first and all code second. Tests target public APIs rather than internal methods or direct database state. Because tests ignore internal structure, later code changes will not break them.

Refactoring is permitted only after reaching green status. Touching code architecture while tests remain red is forbidden.

What it helps with

design testable public interfaces before implementation
verify end-to-end flows with minimal tracer bullet tests
keep tests working during internal code refactors
add features incrementally without speculative code

Example prompts for the agent

Build the shopping cart checkout using TDD and red-green-refactor
Fix the discount calculation bug test-first
Create integration tests for the user registration endpoint

How to install tdd

1Skills CLI (Vercel)

npx skills add brianlovin/agent-config --skill tdd -a claude-code

2Manually: put the files in place

~/.claude/skills/tdd/SKILL.md

Copy the whole skill folder; for one project use .claude/skills/tdd/

1Skills CLI (Vercel)

npx skills add brianlovin/agent-config --skill tdd -a codex

2Manually: put the files in place

.agents/skills/tdd/SKILL.md

For all projects use ~/.agents/skills/

1Skills CLI (Vercel)

npx skills add brianlovin/agent-config --skill tdd -a cursor

2Manually: put the files in place

.cursor/skills/tdd/SKILL.md

Cursor also reads .agents/skills/ and .claude/skills/

1GitHub CLI

gh skill install brianlovin/agent-config tdd

2Manually: put the files in place

.github/skills/tdd/SKILL.md

1Skills CLI (Vercel)

npx skills add brianlovin/agent-config --skill tdd -a gemini-cli

2Platform CLI

gemini skills install https://github.com/brianlovin/agent-config --path skills/tdd

Manually: put the files in place

.devin/skills/tdd/SKILL.md

The legacy .windsurf/skills/ path still works

Skills CLI (Vercel)

npx skills add brianlovin/agent-config --skill tdd -a opencode

Step by step, with commands for each platform: How to install skills in Claude Code: five ways

Questions about tdd

How to install tdd in Claude Code?

Run npx skills add brianlovin/agent-config --skill tdd -a claude-code in your terminal.

What does the tdd skill do?

It directs the coding agent through vertical TDD cycles, pairing each individual failing test with minimal code before refactoring.

Why does the skill discourage writing all tests upfront?

Writing tests in bulk tests speculative structure rather than real system behavior. Incremental cycles allow each test to adapt to what the previous step revealed.

Similar skills

Everything for Testing and QA →

tdd by other authors comes first.

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