Core Web Vitals

by addyosmani

Core Web Vitals is an SEO skill for Claude Code, published by addyosmani in web-quality-skills.

2.6K stars239 forkson addyosmani/web-quality-skillsAdded 2026/08/18+1% in starsRepository updated 2026/06/14

View source on GitHub Download repo ZIP

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Install in seconds

Install Core Web Vitals

Copy Core Web Vitals into your Claude Code skills folder. Run the command in your terminal, or review the source on GitHub before installing.

terminal

npx degit https://github.com/addyosmani/web-quality-skills/tree/main/skills/core-web-vitals ~/.claude/skills/core-web-vitals

Requires Node.js. Downloads this skill only — not the rest of the repository — into your Claude Code skills folder.

Without Node.js

git clone https://github.com/addyosmani/web-quality-skills.git

Clones the whole repository, then copy the skill’s own directory into your skills folder yourself.

In this catalog

Source file: skills/core-web-vitals/SKILL.md in addyosmani/web-quality-skills
Installs to: ~/.claude/skills/core-web-vitals
Collection: One of 6 skills cataloged from this repository
Category: SEO — 164 skills

What Core Web Vitals does

Core Web Vitals optimizes LCP, INP, and CLS to improve page experience and Google Search ranking. Use it when asked to fix LCP, reduce CLS, optimize INP, or resolve page experience and layout shift issues.

Core Web Vitals is cataloged under SEO on DirSkills. Core Web Vitals comes from a repository tagged accessibility, agent-skills, claude-skills, core-web-vitals and lighthouse.

Documentation

README

Excerpt

Core Web Vitals optimization

Targeted optimization for the three Core Web Vitals metrics that affect Google Search ranking and user experience.

The three metrics

Metric	Measures	Good	Needs work	Poor
LCP	Loading	≤ 2.5s	2.5s – 4s	> 4s
INP	Interactivity	≤ 200ms	200ms – 500ms	> 500ms
CLS	Visual Stability	≤ 0.1	0.1 – 0.25	> 0.25

Google measures at the 75th percentile — 75% of page visits must meet "Good" thresholds.

LCP: Largest Contentful Paint

LCP measures when the largest visible content element renders. Usually this is:

Hero image or video
Large text block
Background image
<svg> element

Common LCP issues

This is the opening of the README. Read the full README on GitHub.

Frequently asked about Core Web Vitals

What else does addyosmani publish alongside Core Web Vitals?
Core Web Vitals is one of 6 skills that DirSkills catalogs from addyosmani/web-quality-skills, the repository it ships in. Its siblings there include Accessibility, SEO and Web Best Practices. Each one is a separate skill with its own page in this directory, installs the same way Core Web Vitals does, and is maintained by addyosmani in that same repository. The rest of the collection is listed on the addyosmani/web-quality-skills page.
How does Core Web Vitals compare to other SEO skills?
Core Web Vitals ranks #35 by stars among the 164 SEO skills in this catalog. The most-starred ones next to it are App Store Optimization, Answer Engine Optimization and SEO Analysis. DirSkills ranks by the star count of the repository each skill ships in, so that order reflects how popular those repositories are rather than any review of Core Web Vitals against them. Open each page to compare what they document and how they install.