core-web-vitals

# SEO Technical: Core Web Vitals Guides optimization of Core Web Vitals (CWV)—Google's user experience metrics that affect search ranking. CWV are confirmed ranking factors for mobile and desktop. **When invoking**: On **first use**, if helpful, open with 1–2 sentences on what this skill covers and why it matters, then provide the main output. On **subsequent use** or when the user asks to skip, go directly to the main output. ## Scope (Technical SEO) - **LCP** (Largest Contentful Paint): Loading performance; time to render largest content element - **INP** (Interaction to Next Paint): Responsiveness; replaced FID in March 2024 - **CLS** (Cumulative Layout Shift): Visual stability; unexpected layout shifts ## Target Thresholds (75th percentile, field data) | Metric | Target | Good | Needs Improvement | Poor | |--------|--------|------|-------------------|------| | **LCP** | ≤2.5s | ≤2.5s | 2.5–4.0s | >4.0s | | **INP** | ≤200ms | ≤200ms | 200–500ms | >500ms | | **CLS** | <0.1 | ≤0.1 | 0.1–0.25 | >0.25 | **Source**: [Google Page Experience](https://developers.google.com/search/docs/appearance/page-experience) ## Initial Assessment **Check for project context first:** If `.claude/project-context.md` or `.cursor/project-context.md` exists, read it for site URL. Identify: 1. **Tools**: GSC Core Web Vitals report, PageSpeed Insights, Chrome DevTools 2. **Metrics**: Which metric is failing (LCP, INP, CLS) 3. **Page type**: Hero, article, product, list—LCP candidate differs...