Use when creating or editing any prompt (commands, hooks, skills, subagent instructions) to verify it produces desired behavior - applies RED-GREEN-REFACTOR cycle to prompt engineering using subagents for isolated testing
Install
npx skills add NeoLabHQ/context-engineering-kit --skill test-promptnpx skills add NeoLabHQ/context-engineering-kit --skill test-prompt -a claude-code -gnpx skills add NeoLabHQ/context-engineering-kit --skill test-prompt -a codex -ggemini skills install https://github.com/NeoLabHQ/context-engineering-kit.git --path skills/test-promptgh skill install NeoLabHQ/context-engineering-kit test-promptgit clone --depth 1 https://github.com/NeoLabHQ/context-engineering-kit /tmp/NeoLabHQ__context-engineering-kit
mkdir -p ~/.claude/skills ~/.agents/skills
cp -R /tmp/NeoLabHQ__context-engineering-kit/skills/test-prompt ~/.claude/skills/test-prompt # Claude Code
cp -R /tmp/NeoLabHQ__context-engineering-kit/skills/test-prompt ~/.agents/skills/test-prompt # Codex, Cursor, Gemini CLI, Copilot, OpenCode