Use when designing domain types, when a record has many optional fields, or when choosing between a record, a union, and a bare primitive.
Install
npx skills add yutna/functional-design-skills --skill functional-modeling-with-algebraic-typesnpx skills add yutna/functional-design-skills --skill functional-modeling-with-algebraic-types -a claude-code -gnpx skills add yutna/functional-design-skills --skill functional-modeling-with-algebraic-types -a codex -ggemini skills install https://github.com/yutna/functional-design-skills.git --path plugin/skills/functional-modeling-with-algebraic-typesgh skill install yutna/functional-design-skills functional-modeling-with-algebraic-typesgit 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-modeling-with-algebraic-types ~/.claude/skills/functional-modeling-with-algebraic-types # Claude Code
cp -R /tmp/yutna__functional-design-skills/plugin/skills/functional-modeling-with-algebraic-types ~/.agents/skills/functional-modeling-with-algebraic-types # Codex, Cursor, Gemini CLI, Copilot, OpenCode