Use when a shape could be a type or a generic map, when fields or columns vary by tenant or user, when a schema must be a value, or when wrapper types block generic code.
Install
npx skills add yutna/functional-design-skills --skill functional-choosing-types-or-plain-datanpx skills add yutna/functional-design-skills --skill functional-choosing-types-or-plain-data -a claude-code -gnpx skills add yutna/functional-design-skills --skill functional-choosing-types-or-plain-data -a codex -ggemini skills install https://github.com/yutna/functional-design-skills.git --path plugin/skills/functional-choosing-types-or-plain-datagh skill install yutna/functional-design-skills functional-choosing-types-or-plain-datagit 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-choosing-types-or-plain-data ~/.claude/skills/functional-choosing-types-or-plain-data # Claude Code
cp -R /tmp/yutna__functional-design-skills/plugin/skills/functional-choosing-types-or-plain-data ~/.agents/skills/functional-choosing-types-or-plain-data # Codex, Cursor, Gemini CLI, Copilot, OpenCode