Skills for Developers Who Care About Quality

Make code simpler, faster, and easier to read.

cleanup repeatedly finds duplicated information, repeated work, unnecessary defensive code, and accidental complexity. In a fully tested example, it found 32 significant cleanups and made the codebase 1.34× faster while using less memory.

npx skills add mkanat/skills --skill cleanup

Example

You can see a report of all the cleanups the cleanup skill did on an example codebase, with short diffs showing many of the improvements.

Here's the full story:

I had Codex build a fully-tested, working incremental build system using GPT-5.6 Sol, called minibuild. I had it run a type checker (basedpyright in strict mode), run a full linter (ruff with ALL checks enabled), and do auto-formatting. I also had it check code coverage and add missing tests, so it has 100% coverage without any mocking. I did not otherwise review or modify its code.

You can see the before version in examples/minibuild/before/.

I then ran cleanup on that codebase. It ran by itself five times in a row and did 9 significant refactorings. I then manually triggered cleanup five more times. It ran itself in loops a bunch of times and made 23 more cleanups.

The after version is in examples/minibuild/after/.

You can see the full diff between before and after, if you want.

The cleanup dramatically improved the code structure, but it also made real functional improvements to the system. It removed repeated work, stopped keeping multiple copies of the same information, and avoided redoing work when the final result had not actually changed. On a 10,001-task benchmark, the cleaned-up version actually ran 1.34× faster while using less memory. (You can see the full performance-testing harness and results in examples/minibuild/performance/.)

Install

Any agent supported by skills.sh

The skills CLI supports Codex, Claude Code, Cursor, GitHub Copilot, Gemini CLI, Windsurf, Cline, OpenCode, and many other agents:

npx skills add mkanat/skills

The CLI lets you choose the skill and target agents interactively. To install cleanup non-interactively:

npx skills add mkanat/skills --skill cleanup

Claude Code plugin

claude plugin marketplace add mkanat/skills
claude plugin install mkanat-skills@mkanat

Invoke the installed skill as /mkanat-skills:cleanup.

Codex plugin

codex plugin marketplace add mkanat/skills
codex plugin add mkanat-skills@mkanat

Invoke the installed skill as $cleanup.

Manual installation

Copy skills/cleanup into an agent's skills directory. The common cross-agent location is ~/.agents/skills/cleanup; project-local locations include .agents/skills/cleanup, .claude/skills/cleanup, and .github/skills/cleanup.

License

To maximize reuse, this repository is dedicated to the public domain under CC0 1.0 Universal. You may copy, modify, and distribute it for any purpose without asking permission.