Check prose with chaff (npx chaffjs): pick the genre preset for the kind of document (contract, statute, manual, FAQ, paper, fiction, transcript…), run it on Markdown or text, read each finding, fix the text or record why not, and tune chaff.yaml with rules --json and relax --why.
Install
npx skills add isamu/lab --skill chaffnpx skills add isamu/lab --skill chaff -a claude-code -gnpx skills add isamu/lab --skill chaff -a codex -ggemini skills install https://github.com/isamu/lab.git --path text/packages/chaff/skills/chaffgh skill install isamu/lab chaffgit clone --depth 1 https://github.com/isamu/lab /tmp/isamu__lab
mkdir -p ~/.claude/skills ~/.agents/skills
cp -R /tmp/isamu__lab/text/packages/chaff/skills/chaff ~/.claude/skills/chaff # Claude Code
cp -R /tmp/isamu__lab/text/packages/chaff/skills/chaff ~/.agents/skills/chaff # Codex, Cursor, Gemini CLI, Copilot, OpenCode