Test-driven development, red then green, one vertical slice at a time. Use when building a feature, a rule, a config option or a bug fix test-first, when the user says "TDD", "red-green" or "write the test first", or when a subagent is handed a ticket to build.
Install
npx skills add ehnruiz/claude-skills --skill tddnpx skills add ehnruiz/claude-skills --skill tdd -a claude-code -gnpx skills add ehnruiz/claude-skills --skill tdd -a codex -ggemini skills install https://github.com/ehnruiz/claude-skills.git --path skills/tddgh skill install ehnruiz/claude-skills tddgit clone --depth 1 https://github.com/ehnruiz/claude-skills /tmp/ehnruiz__claude-skills
mkdir -p ~/.claude/skills ~/.agents/skills
cp -R /tmp/ehnruiz__claude-skills/skills/tdd ~/.claude/skills/tdd # Claude Code
cp -R /tmp/ehnruiz__claude-skills/skills/tdd ~/.agents/skills/tdd # Codex, Cursor, Gemini CLI, Copilot, OpenCode