Agent skill

Web Performance Audit

Web performance audits with Core Web Vitals, bottleneck identification, optimization recommendations.

Install Web Performance Audit

skills CLI

$ npx skills add secondsky/claude-skills --skill web-performance-audit -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI

$ gh skill install secondsky/claude-skills web-performance-audit --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy

$ git clone --depth 1 https://github.com/secondsky/claude-skills.git skills-src && mkdir -p .claude/skills && cp -r skills-src/plugins/web-performance-audit/skills/web-performance-audit .claude/skills/web-performance-audit && rm -rf skills-src

Use ~/.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/

Paste into Claude Code

Install the "web-performance-audit" agent skill from https://github.com/secondsky/claude-skills/tree/main/plugins/web-performance-audit/skills/web-performance-audit into .claude/skills/web-performance-audit/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "web-performance-audit", 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

$skill-installer install https://github.com/secondsky/claude-skills/tree/main/plugins/web-performance-audit/skills/web-performance-audit

Type 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.

skills CLI

$ npx skills add secondsky/claude-skills --skill web-performance-audit -a codex

Project install goes to .agents/skills/; add -g for ~/.codex/skills/.

GitHub CLI

$ gh skill install secondsky/claude-skills web-performance-audit --agent codex

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/secondsky/claude-skills.git skills-src && mkdir -p .agents/skills && cp -r skills-src/plugins/web-performance-audit/skills/web-performance-audit .agents/skills/web-performance-audit && rm -rf skills-src

Use ~/.agents/skills/ instead of .agents/skills for a personal install.

Codex skills documentation · loads skills from .agents/skills/

Paste into Codex

Install the "web-performance-audit" agent skill from https://github.com/secondsky/claude-skills/tree/main/plugins/web-performance-audit/skills/web-performance-audit into .agents/skills/web-performance-audit/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "web-performance-audit", 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.

skills CLI

$ npx skills add secondsky/claude-skills --skill web-performance-audit -a cursor

Project install goes to .agents/skills/; add -g for ~/.cursor/skills/.

GitHub CLI

$ gh skill install secondsky/claude-skills web-performance-audit --agent cursor

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/secondsky/claude-skills.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/plugins/web-performance-audit/skills/web-performance-audit .cursor/skills/web-performance-audit && rm -rf skills-src

Use ~/.cursor/skills/ instead of .cursor/skills for a personal install.

Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/

Paste into Cursor

Install the "web-performance-audit" agent skill from https://github.com/secondsky/claude-skills/tree/main/plugins/web-performance-audit/skills/web-performance-audit into .cursor/skills/web-performance-audit/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "web-performance-audit", 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

$ gemini skills install https://github.com/secondsky/claude-skills.git --path plugins/web-performance-audit/skills/web-performance-audit

--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.

skills CLI

$ npx skills add secondsky/claude-skills --skill web-performance-audit -a gemini-cli

Project install goes to .agents/skills/; add -g for ~/.gemini/skills/.

GitHub CLI

$ gh skill install secondsky/claude-skills web-performance-audit --agent gemini-cli

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/secondsky/claude-skills.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/plugins/web-performance-audit/skills/web-performance-audit .gemini/skills/web-performance-audit && rm -rf skills-src

Use ~/.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/

Paste into Gemini CLI

Install the "web-performance-audit" agent skill from https://github.com/secondsky/claude-skills/tree/main/plugins/web-performance-audit/skills/web-performance-audit into .gemini/skills/web-performance-audit/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "web-performance-audit", 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.

GitHub CLI

$ gh skill install secondsky/claude-skills web-performance-audit

Installs 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).

skills CLI

$ npx skills add secondsky/claude-skills --skill web-performance-audit -a github-copilot

Project install goes to .agents/skills/; add -g for ~/.copilot/skills/.

Manual copy

$ git clone --depth 1 https://github.com/secondsky/claude-skills.git skills-src && mkdir -p .github/skills && cp -r skills-src/plugins/web-performance-audit/skills/web-performance-audit .github/skills/web-performance-audit && rm -rf skills-src

Use ~/.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/

Paste into GitHub Copilot

Install the "web-performance-audit" agent skill from https://github.com/secondsky/claude-skills/tree/main/plugins/web-performance-audit/skills/web-performance-audit into .github/skills/web-performance-audit/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "web-performance-audit", 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.

skills CLI

$ npx skills add secondsky/claude-skills --skill web-performance-audit -a opencode

OpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.

GitHub CLI

$ gh skill install secondsky/claude-skills web-performance-audit --agent opencode

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/secondsky/claude-skills.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/plugins/web-performance-audit/skills/web-performance-audit .opencode/skills/web-performance-audit && rm -rf skills-src

Use ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.

OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/

Paste into OpenCode

Install the "web-performance-audit" agent skill from https://github.com/secondsky/claude-skills/tree/main/plugins/web-performance-audit/skills/web-performance-audit into .opencode/skills/web-performance-audit/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "web-performance-audit", 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: web-performance-audit
GitHub stars: 227
Token cost: ~642 tokens
SKILL.md length: 140 words
Files: 1
Skills in repo: 169
Repo updated: Sep 28, 2026
First seen: Oct 7, 2026
Licence: MIT

At a glance

Web performance audits with Core Web Vitals, bottleneck identification, optimization recommendations.

Page load times
SKILL.md covers Core Web Vitals Targets, Performance Measurement, Lighthouse Automation and Optimization Strategies, plus 2 more sections
Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
Performance reviews

What it does

Web Performance Audit is an agent skill from secondsky/claude-skills. Web performance audits with Core Web Vitals, bottleneck identification, optimization recommendations. Use for page load times, performance reviews, UX optimization, or encountering LCP, FID, CLS issues, resource blocking, render delays.

Its SKILL.md is about 640 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. The repository describes itself as: Production-ready skills for Claude Code CLI - Cloudflare, React, Tailwind v4, and AI integrations. The licence is MIT.

When your agent uses it

Page load times
Performance reviews
UX optimization
Encountering LCP

Example prompts

“/web-performance-audit”

What it can do on your machine

Read from SKILL.md and the folder at commit 8837836. 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 (its code samples are javascript and json).
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md.
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

Web Performance Audit loads about 642 tokens when it runs. Until then it costs about 65 tokens; SKILL.md has 140 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it: ~65
When it runs · the whole SKILL.md, loaded when a task matches: ~642

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 secondsky/claude-skills at commit 8837836, republished under its MIT licence (© secondsky). 140 words, ~642 tokens.

Download SKILL.mdSave it as .claude/skills/web-performance-audit/SKILL.md (or your agent's skills folder).

name: web-performance-audit
description: Web performance audits with Core Web Vitals, bottleneck identification, optimization recommendations. Use for page load times, performance reviews, UX optimization, or encountering LCP, FID, CLS issues, resource blocking, render delays.
license: MIT

Web Performance Audit

Conduct comprehensive performance audits and implement optimizations.

Core Web Vitals Targets

Metric	Good	Needs Improvement	Poor
LCP (Largest Contentful Paint)	<2.5s	2.5-4s	>4s
FID (First Input Delay)	<100ms	100-300ms	>300ms
CLS (Cumulative Layout Shift)	<0.1	0.1-0.25	>0.25
INP (Interaction to Next Paint)	<200ms	200-500ms	>500ms

Performance Measurement

javascript

// Using web-vitals library
import { getCLS, getFID, getLCP, getTTFB } from 'web-vitals';

function sendToAnalytics({ name, value, id }) {
  console.log({ name, value, id });
}

getCLS(sendToAnalytics);
getFID(sendToAnalytics);
getLCP(sendToAnalytics);
getTTFB(sendToAnalytics);

Lighthouse Automation

javascript

const lighthouse = require('lighthouse');
const chromeLauncher = require('chrome-launcher');

async function runAudit(url) {
  const chrome = await chromeLauncher.launch({ chromeFlags: ['--headless'] });
  const result = await lighthouse(url, {
    port: chrome.port,
    onlyCategories: ['performance']
  });

  await chrome.kill();
  return result.lhr;
}

Optimization Strategies

Quick Wins (1-2 days)

Enable gzip/brotli compression
Minify CSS/JS
Defer non-critical scripts
Optimize images (WebP, lazy loading)

Medium Effort (1-2 weeks)

Implement code splitting
Add service worker caching
Preload critical resources
Eliminate render-blocking resources

Long-term (1-3 months)

Architecture improvements
CDN optimization
Database query optimization

Performance Budget

json

{
  "timings": [
    { "metric": "first-contentful-paint", "budget": 1500 },
    { "metric": "largest-contentful-paint", "budget": 2500 }
  ],
  "resourceSizes": [
    { "resourceType": "script", "budget": 150 },
    { "resourceType": "image", "budget": 300 }
  ]
}

Audit Checklist

Measure baseline Core Web Vitals
Run Lighthouse audit (mobile & desktop)
Analyze real user metrics (RUM)
Identify largest contentful element
Check for layout shifts
Review JavaScript bundle size
Test on slow 3G connection
Set performance budget
Configure monitoring alerts

Files

Just SKILL.md in plugins/web-performance-audit/skills/web-performance-audit of secondsky/claude-skills.

Open the folder on GitHubat commit 8837836

Compare with similar skills

Web Performance Audit 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.

Web Performance Audit compared with similar skills
Skill	Stars	Used in	Tokens	Auto-check	Licence	Repo updated
Web Performance Audit this skillsecondsky/claude-skills	227	—	~642	Automated safety check: Pass	MIT	10 days ago
React Doctormakeplane/plane	61k	12 repos	~657	Automated safety check: Pass	AGPL-3.0	yesterday
Fixing Motion Performanceibelick/ui-skills	9.5k	5 repos	~1.4k	Automated safety check: Pass	MIT	yesterday
GSAP Performance Tuninggreensock/gsap-skills	16k	4 repos	~1k	Automated safety check: Pass	MIT	2 mo ago
React Frontend Development Guidelinesdiet103/claude-code-infrastructure-showcase	10k	2 repos	~2.9k	Automated safety check: Pass	MIT	2 mo ago
Web Quality Auditaddyosmani/web-quality-skills	2.9k	—	~2.6k	Automated safety check: Pass	MIT	1 mo ago

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Questions about Web Performance Audit

What does Web Performance Audit do?

Web performance audits with Core Web Vitals, bottleneck identification, optimization recommendations. Web Performance Audit is an agent skill from secondsky/claude-skills. Web performance audits with Core Web Vitals, bottleneck identification, optimization recommendations.

When should I use Web Performance Audit?

Web Performance Audit fits situations like: page load times; performance reviews; UX optimization; encountering LCP.

How do I install Web Performance Audit in Claude Code?

Run `npx skills add secondsky/claude-skills --skill web-performance-audit -a claude-code`. Or copy the skill folder (plugins/web-performance-audit/skills/web-performance-audit in secondsky/claude-skills) into .claude/skills/web-performance-audit in your project. Claude Code loads it when a task matches its description.

How do I install Web Performance Audit in Codex?

Run `npx skills add secondsky/claude-skills --skill web-performance-audit -a codex`. Or copy the skill folder (plugins/web-performance-audit/skills/web-performance-audit in secondsky/claude-skills) into .agents/skills/web-performance-audit in your project. Codex loads it when a task matches its description.

Can I use Web Performance Audit 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 secondsky/claude-skills --skill web-performance-audit -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/web-performance-audit, .gemini/skills/web-performance-audit, .github/skills/web-performance-audit and .opencode/skills/web-performance-audit in your project.

What does Web Performance Audit need to run?

SKILL.md names no scripts, command-line tools or credentials: Web Performance Audit is instructions for the agent only.

Does Web Performance Audit access the network?

SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.

Is Web Performance Audit 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 Web Performance Audit use?

Web Performance Audit is published under the MIT licence (declared in SKILL.md). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Web Performance Audit use?

About 642 tokens (SKILL.md is roughly 2.6k 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 Web Performance Audit?

Skills that share tags, products or a category with Web Performance Audit: React Doctor (makeplane/plane, 61k stars), Fixing Motion Performance (ibelick/ui-skills, 9.5k stars), GSAP Performance Tuning (greensock/gsap-skills, 16k stars) and React Frontend Development Guidelines (diet103/claude-code-infrastructure-showcase, 10k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Web Performance Audit?

secondsky (a GitHub user) maintains it in secondsky/claude-skills, which has 227 GitHub stars. The repository holds 169 skills in this directory. The repository was last updated on September 28, 2026.

Source: secondsky/claude-skills on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.

Install Web Performance Audit

Facts

At a glance

What it does

When your agent uses it

Example prompts

What it can do on your machine

Tool permissions

Runs code

Network

Credentials

Context cost

Safety

SKILL.md

Web Performance Audit

Core Web Vitals Targets

Performance Measurement

Lighthouse Automation

Optimization Strategies

Quick Wins (1-2 days)

Medium Effort (1-2 weeks)

Long-term (1-3 months)

Performance Budget

Audit Checklist

Files

Compare with similar skills

Similar skills

More from secondsky/claude-skills

Related

Questions about Web Performance Audit