performance-optimization

Use when creating performance optimization plan for backend, API, or general system performance. Enforces BASELINE → PROFILE → OPTIMIZE → VALIDATE sequence. Triggers: "optimize API", "backend slow", "API latency", "database performance", "query optimization", "server response time". For "Core Web Vitals" in backend/API context, use this skill. For frontend UI accessibility + performance (WCAG, Lighthouse accessibility), use frontend-production-quality instead. If thinking "bottleneck is obvious" - profile first.