Core Web Vitals

This one walks you through fixing Google's Core Web Vitals: LCP (loading speed), INP (interaction responsiveness), and CLS (layout stability). It covers the current thresholds (like LCP under 2.5s, INP under 200ms), explains what's breaking each metric, and gives you specific fixes like deferring render-blocking resources, setting image dimensions to prevent shifts, and breaking up long JavaScript tasks. The initial assessment checks your project context files for the site URL, which is a nice touch. It's essentially a diagnostic checklist that knows when to pull in related skills for image optimization or rendering strategies. Saves you from piecing together fragmented PageSpeed Insights recommendations.

skills.sh installs: 1.1K
GitHub stars: 1.1K
last updated: Aug 21, 2026

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Install

$ npx -y skills add kostja94/marketing-skills --skill core-web-vitals --agent claude-code

Installs into .claude/skills of the current project.

Files

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 on March 12, 2024
CLS (Cumulative Layout Shift): Visual stability; unexpected layout shifts