Skills are modular instruction packages (plugins) that give AI coding agents domain expertise they don't have out of the box. Each skill includes a SKILL.md (instructions + workflows), Python CLI tools, and reference documentation — everything the agent needs to perform like a specialist.
One repo, four platforms: Works natively as Claude Code plugins, OpenAI Codex CLI and agents, Gemini CLI skills, and OpenClaw skills. All 237 Python tools are stdlib-only and verified working.