Use when deciding what to log, trace, or measure, when an incident could not be diagnosed from what was recorded, or when adding observability late.
Install
npx skills add yutna/functional-design-skills --skill functional-designing-what-to-observenpx skills add yutna/functional-design-skills --skill functional-designing-what-to-observe -a claude-code -gnpx skills add yutna/functional-design-skills --skill functional-designing-what-to-observe -a codex -ggemini skills install https://github.com/yutna/functional-design-skills.git --path plugin/skills/functional-designing-what-to-observegh skill install yutna/functional-design-skills functional-designing-what-to-observegit 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-designing-what-to-observe ~/.claude/skills/functional-designing-what-to-observe # Claude Code
cp -R /tmp/yutna__functional-design-skills/plugin/skills/functional-designing-what-to-observe ~/.agents/skills/functional-designing-what-to-observe # Codex, Cursor, Gemini CLI, Copilot, OpenCode