domains / families / software-engineering / core-web-vitals
Optimize Core Web Vitals (LCP, INP, CLS) for better page experience using field and lab evidence. Use when asked to "improve Core Web Vitals", "fix LCP", "reduce CLS", "optimize INP", "page experience optimization", or "fix layout shifts". When the user wants to optimize Core Web Vitals, fix LCP, INP, or CLS issues. Also use when the user mentions "Core Web Vitals," "CWV," "LCP," "INP," "CLS," "FID," "page speed," "page performance," "Largest Contentful Paint," "Interaction to Next Paint," "Cumulative Layout Shift," or "Page Experience." For GSC CWV, use google-search-console.
Both copies cover the same three metrics and thresholds, but each contains material steps the other lacks. The first copy is a technical-SEO triage skill with an initial assessment workflow, a cause/fix matrix for LCP/INP/CLS, a tools table, and an output format. The second copy is a measurement-first engineering skill that requires field data (CrUX p75) and browser traces before claiming a failure, includes concrete code patterns for render-blocking CSS, LCP image discovery, SSR, and the Speculation Rules API, and adds a re-measurement rule. Crowning one would hide the other's real alternative approach (SEO triage vs. evidence-driven lab/field workflow).