SEO Google
AgriciDaniel/codex-seo
Google SEO APIs: Search Console (Search Analytics, URL Inspection, Sitemaps), PageSpeed Insights v5, CrUX field data with 25-week history, Indexing API v3, and GA4 organic traffic.
When the user wants to optimize Core Web Vitals, fix LCP, INP, or CLS issues.
Install Core Web Vitals
$ npx skills add kostja94/marketing-skills --skill core-web-vitals -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install kostja94/marketing-skills core-web-vitals --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/kostja94/marketing-skills.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/seo/technical/core-web-vitals .claude/skills/core-web-vitals && rm -rf skills-srcUse ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.
Claude Code skills documentation · loads skills from .claude/skills/
Install the "core-web-vitals" agent skill from https://github.com/kostja94/marketing-skills/tree/main/skills/seo/technical/core-web-vitals into .claude/skills/core-web-vitals/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "core-web-vitals", then confirm the skill loads.Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$skill-installer install https://github.com/kostja94/marketing-skills/tree/main/skills/seo/technical/core-web-vitalsType this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
$ npx skills add kostja94/marketing-skills --skill core-web-vitals -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install kostja94/marketing-skills core-web-vitals --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/kostja94/marketing-skills.git skills-src && mkdir -p .agents/skills && cp -r skills-src/skills/seo/technical/core-web-vitals .agents/skills/core-web-vitals && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "core-web-vitals" agent skill from https://github.com/kostja94/marketing-skills/tree/main/skills/seo/technical/core-web-vitals into .agents/skills/core-web-vitals/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "core-web-vitals", then confirm the skill loads.Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add kostja94/marketing-skills --skill core-web-vitals -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install kostja94/marketing-skills core-web-vitals --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/kostja94/marketing-skills.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/skills/seo/technical/core-web-vitals .cursor/skills/core-web-vitals && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "core-web-vitals" agent skill from https://github.com/kostja94/marketing-skills/tree/main/skills/seo/technical/core-web-vitals into .cursor/skills/core-web-vitals/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "core-web-vitals", then confirm the skill loads.Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gemini skills install https://github.com/kostja94/marketing-skills.git --path skills/seo/technical/core-web-vitals--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add kostja94/marketing-skills --skill core-web-vitals -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install kostja94/marketing-skills core-web-vitals --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/kostja94/marketing-skills.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/skills/seo/technical/core-web-vitals .gemini/skills/core-web-vitals && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "core-web-vitals" agent skill from https://github.com/kostja94/marketing-skills/tree/main/skills/seo/technical/core-web-vitals into .gemini/skills/core-web-vitals/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "core-web-vitals", then confirm the skill loads.Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gh skill install kostja94/marketing-skills core-web-vitalsInstalls for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
$ npx skills add kostja94/marketing-skills --skill core-web-vitals -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/kostja94/marketing-skills.git skills-src && mkdir -p .github/skills && cp -r skills-src/skills/seo/technical/core-web-vitals .github/skills/core-web-vitals && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "core-web-vitals" agent skill from https://github.com/kostja94/marketing-skills/tree/main/skills/seo/technical/core-web-vitals into .github/skills/core-web-vitals/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "core-web-vitals", then confirm the skill loads.GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add kostja94/marketing-skills --skill core-web-vitals -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install kostja94/marketing-skills core-web-vitals --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/kostja94/marketing-skills.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/skills/seo/technical/core-web-vitals .opencode/skills/core-web-vitals && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "core-web-vitals" agent skill from https://github.com/kostja94/marketing-skills/tree/main/skills/seo/technical/core-web-vitals into .opencode/skills/core-web-vitals/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "core-web-vitals", then confirm the skill loads.OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
Facts
- Skill name
core-web-vitals- GitHub stars
- 1k
- Token cost
- ~1.2k tokens
- SKILL.md length
- 483 words
- Files
- 1
- Skills in repo
- 102
- Repo updated
- First seen
- Licence
- MIT
At a glance
When the user wants to optimize Core Web Vitals, fix LCP, INP, or CLS issues.
- Works in 3 steps: Tools: GSC Core Web Vitals report,… → Metrics: Which metric is failing (LCP,… → Page type: Hero, article, product,…
- Wants to optimize Core Web Vitals
- SKILL.md covers Scope (Technical SEO), Target Thresholds (75th…, Initial Assessment and LCP Optimization, plus 5 more sections
- Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
What it does
Core Web Vitals is an agent skill from kostja94/marketing-skills. 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.
Its SKILL.md is about 1.2k tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.
It sits in Frontend & Design, covering Web performance. It works with Contentful and Google Search Console. The repository describes itself as: Agent Skills for Marketing — SEO, Social, Influencer & More. 160+ open-source skills for SEO, content, 40+ page types, paid ads, channels, and strategies. Add project context… The licence is MIT.
When your agent uses it
- Wants to optimize Core Web Vitals
- The user mentions Core Web Vitals
- Page performance
- Largest Contentful Paint
Example prompts
- “Core Web Vitals,”
- “page speed,”
- “page performance,”
- “/core-web-vitals”
Workflow steps
3 steps, taken from the first numbered list in SKILL.md.
- Tools: GSC Core Web Vitals report, PageSpeed Insights, Chrome DevTools
- Metrics: Which metric is failing (LCP, INP, CLS)
- Page type: Hero, article, product, list—LCP candidate differs
What it can do on your machine
Read from SKILL.md and the folder at commit 8dd89c5. It shows what the files ask for, not the result of running them.
Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
No scripts in the folder and no shell commands in SKILL.md.
From the folder's file list and the shell code blocks in SKILL.md.
Network
Links to these hosts (documentation or services it may open):
developers.google.comweb.dev
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.
Context cost
Core Web Vitals loads about 1.2k tokens when it runs. Until then it costs about 90 tokens; SKILL.md has 483 words of instructions outside code blocks.
Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.
Safety
Auto-check passed
The automated check found no risky patterns in SKILL.md.
Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.
SKILL.md
The full file from kostja94/marketing-skills at commit 8dd89c5, republished under its MIT licence (© kostja94). 483 words, ~1,164 tokens.
Download SKILL.mdSave it as
.claude/skills/core-web-vitals/SKILL.md (or your agent's skills folder).- name
- core-web-vitals
- description
- 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.
- metadata.version
- 1.0.2
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
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
Initial Assessment
Project context: Read root contextus.md when present and load only the modules relevant to this task. Without Contextus, use available project material or user-provided facts and ask for missing information; do not create a parallel context system.
Identify:
- Tools: GSC Core Web Vitals report, PageSpeed Insights, Chrome DevTools
- Metrics: Which metric is failing (LCP, INP, CLS)
- Page type: Hero, article, product, list—LCP candidate differs
LCP Optimization
LCP measures the time until the largest content element (image, video, or text block) is visible.
| Cause | Fix |
|---|---|
| Slow server response | Reduce TTFB; use CDN; optimize server |
| Render-blocking resources | Defer non-critical CSS/JS; inline critical CSS |
| Large images | WebP/AVIF; compress; width/height to prevent CLS; see image-optimization |
| Client-side rendering | SSR/SSG for above-fold content; see rendering-strategies |
| Third-party scripts | Load async; defer non-critical |
LCP candidates: Hero image, large text block, video poster. Ensure above-fold images use loading="eager" (default); never lazy-load LCP.
Show full SKILL.md (199 more words)Show less
INP Optimization
INP measures responsiveness—time from user interaction to next paint. Replaced FID on March 12, 2024.
| Cause | Fix |
|---|---|
| Long-running JS | Break tasks >50ms; use requestIdleCallback; Web Workers |
| Heavy event handlers | Debounce/throttle; defer non-critical work |
| Main thread blocking | Reduce third-party scripts; defer non-critical JS |
| Layout thrashing | Batch DOM reads/writes; avoid forced reflows |
CLS Optimization
CLS measures unexpected layout shifts.
| Cause | Fix |
|---|---|
| Images without dimensions | Always set width and height attributes |
| Dynamic content | Reserve space for ads, embeds; use min-height |
| Web fonts | font-display: optional or swap; preload critical fonts |
| Animations | Use transform instead of top/left/width |
Reserve space: For images, ads, embeds—define dimensions before load. Avoid inserting content above existing content without reserved space.
Tools & Monitoring
| Tool | Use |
|---|---|
| GSC | Core Web Vitals report; URL grouping; field data |
| PageSpeed Insights | Lab + field data; mobile + desktop |
| Chrome DevTools | Performance panel; LCP element; layout shift overlay |
Output Format
- Current state: Which metrics fail (LCP, INP, CLS)
- Prioritized fixes: By impact
- References: Web Vitals, Page Experience
Related Skills
- image-optimization: LCP image optimization; WebP; lazy loading (below-fold only)
- google-search-console: CWV report; field data monitoring
- mobile-friendly: Mobile-first indexing; mobile CWV targets
- rendering-strategies: SSR/SSG for LCP; content in initial HTML
- site-crawlability: Redirect chains waste crawl; fix for performance
© kostja94, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file
Files
Just SKILL.md in skills/seo/technical/core-web-vitals of kostja94/marketing-skills.
Open the folder on GitHubat commit 8dd89c5
Compare with similar skills
Core Web Vitals next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| Core Web Vitals this skillkostja94/marketing-skills | 1k | — | ~1.2k | Automated safety check: Pass | MIT | |
| SEO GoogleAgriciDaniel/codex-seo | 799 | 2 repos | ~3.4k | Automated safety check: Pass | MIT | |
| Core Web Vitalstheopenco/llmgateway | 1.7k | — | ~955 | Automated safety check: Pass | Custom licence | |
| First Contentful Paintthedaviddias/Front-End-Checklist | 74k | — | ~427 | Automated safety check: Pass | MIT | |
| Largest Contentful Paintthedaviddias/Front-End-Checklist | 74k | — | ~441 | Automated safety check: Pass | MIT | |
| Performance ProfilerEliasOulkadi/shokunin | 114 | — | ~2.7k | Automated safety check: Notes | MIT |
Similar skills
Core Web Vitals
theopenco/llmgateway
Diagnose and improve Largest Contentful Paint, Interaction to Next Paint, and Cumulative Layout Shift in this repository's Next.js App Router frontends.
First Contentful Paint
thedaviddias/Front-End-Checklist
A skill your agent uses when auditing slow page loads, heavy assets, or rendering delays related to Optimize first contentful paint.
Largest Contentful Paint
thedaviddias/Front-End-Checklist
A skill your agent uses when auditing slow page loads, heavy assets, or rendering delays related to Optimize largest contentful paint.
Performance Profiler
EliasOulkadi/shokunin
Performance profiling and optimization for web apps — Core Web Vitals (LCP, INP, CLS), Lighthouse audits, bundle analysis, backend profiling (CPU, memory, DB queries), N+1 detection, caching…
Algo SEO Technical
asgard-ai-platform/skills
Optimize Core Web Vitals (LCP, INP, CLS) for better search rankings and user experience.
More from kostja94/marketing-skills
All 102 skills in this repoGrokipedia Recommendations
kostja94/marketing-skills
When the user wants to add recommendations, links, or content to Grokipedia.
AI Traffic Tracking
kostja94/marketing-skills
When the user wants to track AI search traffic in GA4 or GSC.
Analytics Tracking
kostja94/marketing-skills
When the user wants to set up, audit, or optimize analytics tracking (GA4, events, conversions).
Brand Visual Generator
kostja94/marketing-skills
When the user wants to define, audit, or apply visual identity (typography, colors, spacing, design tokens, frontend aesthetics).
Canonical Tag
kostja94/marketing-skills
When the user wants to configure canonical URLs, fix duplicate content, or consolidate URL signals.
Content Strategy
kostja94/marketing-skills
When the user wants to plan content for SEO, create content calendar, or build topic clusters.
Related
Works with
Categories
Questions about Core Web Vitals
What does Core Web Vitals do?
When the user wants to optimize Core Web Vitals, fix LCP, INP, or CLS issues. Core Web Vitals is an agent skill from kostja94/marketing-skills. When the user wants to optimize Core Web Vitals, fix LCP, INP, or CLS issues.
When should I use Core Web Vitals?
Core Web Vitals fits situations like: wants to optimize Core Web Vitals; the user mentions Core Web Vitals; page performance; largest Contentful Paint.
How do I install Core Web Vitals in Claude Code?
Run `npx skills add kostja94/marketing-skills --skill core-web-vitals -a claude-code`. Or copy the skill folder (skills/seo/technical/core-web-vitals in kostja94/marketing-skills) into .claude/skills/core-web-vitals in your project. Claude Code loads it when a task matches its description.
How do I install Core Web Vitals in Codex?
Run `npx skills add kostja94/marketing-skills --skill core-web-vitals -a codex`. Or copy the skill folder (skills/seo/technical/core-web-vitals in kostja94/marketing-skills) into .agents/skills/core-web-vitals in your project. Codex loads it when a task matches its description.
Can I use Core Web Vitals in Cursor, Gemini CLI or GitHub Copilot?
Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add kostja94/marketing-skills --skill core-web-vitals -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/core-web-vitals, .gemini/skills/core-web-vitals, .github/skills/core-web-vitals and .opencode/skills/core-web-vitals in your project.
What does Core Web Vitals need to run?
SKILL.md names no scripts, command-line tools or credentials: Core Web Vitals is instructions for the agent only.
Does Core Web Vitals access the network?
SKILL.md names 2 domains. As links in the text: developers.google.com and web.dev. This is read from the text; nothing was executed.
Is Core Web Vitals safe to install?
Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.
What licence does Core Web Vitals use?
Core Web Vitals is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.
How many tokens does Core Web Vitals use?
About 1.2k tokens (SKILL.md is roughly 4.7k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.
What are the alternatives to Core Web Vitals?
Skills that share tags, products or a category with Core Web Vitals: SEO Google (AgriciDaniel/codex-seo, 799 stars), Core Web Vitals (theopenco/llmgateway, 1.7k stars), First Contentful Paint (thedaviddias/Front-End-Checklist, 74k stars) and Largest Contentful Paint (thedaviddias/Front-End-Checklist, 74k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Core Web Vitals?
kostja94 (a GitHub user) maintains it in kostja94/marketing-skills, which has 1,025 GitHub stars. The repository holds 102 skills in this directory. The repository was last updated on October 6, 2026.
Source: kostja94/marketing-skills on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.