Use when a small change touches many files, an edit breaks an unexpected module, code is slow to read, or before refactoring a flag, cache or field that may be self-inflicted.
Install
npx skills add yutna/functional-design-skills --skill functional-diagnosing-complexitynpx skills add yutna/functional-design-skills --skill functional-diagnosing-complexity -a claude-code -gnpx skills add yutna/functional-design-skills --skill functional-diagnosing-complexity -a codex -ggemini skills install https://github.com/yutna/functional-design-skills.git --path plugin/skills/functional-diagnosing-complexitygh skill install yutna/functional-design-skills functional-diagnosing-complexitygit clone --depth 1 https://github.com/yutna/functional-design-skills /tmp/yutna__functional-design-skills
mkdir -p ~/.claude/skills ~/.agents/skills
cp -R /tmp/yutna__functional-design-skills/plugin/skills/functional-diagnosing-complexity ~/.claude/skills/functional-diagnosing-complexity # Claude Code
cp -R /tmp/yutna__functional-design-skills/plugin/skills/functional-diagnosing-complexity ~/.agents/skills/functional-diagnosing-complexity # Codex, Cursor, Gemini CLI, Copilot, OpenCode