---
title: "Core Web Vitals audit | SEO Skill"
description: "Run Lighthouse for one URL, add available CrUX field data and see the Core Web Vitals evidence behind the highest-impact fixes for one page."
canonical: "https://seoskill.dev/docs/reports/performance-audit"
language: "en"
---

# Core Web Vitals audit

Measure one page with local Lighthouse data and available Chrome field evidence. Lab and field results answer different questions, so the audit keeps them separate.

## Install and run the audit

Install the CLI once, then run `seo start` to connect your site and Google data. After setup you can run this audit yourself or ask your agent to run it.

Install the SEO CLI globally.

```
npm i -g seo
```

Run setup after installation.

```
seo start
```

Run a local Lighthouse test and add available CrUX evidence.

```
seo perf audit --url https://example.com/page
```

## What you get from this audit

Run Lighthouse for one URL, add available CrUX field data and see the Core Web Vitals evidence behind the highest-impact fixes for one page.

Best for

A page needs LCP, INP, CLS, TBT, or loading diagnostics.

Needs

Local Lighthouse navigation

You get

Run Lighthouse for one URL, add available CrUX field data and see the Core Web Vitals evidence behind the highest-impact fixes for one page.

Use next

Audit one page

Every report follows the same rules for missing data and outside estimates.[See how report data works](https://seoskill.dev/docs/reports#how-report-data-works).

## What you need before you run it

The report uses the information below. Optional sources are only used when you ask for them.

### Local Lighthouse navigation

Provides lab performance metrics, diagnostics, and opportunities for the selected device strategy.

### Optional CrUX field data

Provides device-specific p75 Core Web Vitals when the URL or origin has enough eligible traffic.

## Use a different report for these jobs

These jobs need a different report or a manual review.

[

### You need technical SEO evidence beyond loading performance for this URL.

Audit the page to add redirects, canonicals, directives, metadata, headings, links, schema, and content evidence. Lighthouse and CrUX do not answer those questions.

SEO page audit

](https://seoskill.dev/docs/reports/audit-page)

### You need to conclude that one Lighthouse run represents every page using the same template.

No automated report can generalise one lab run to a whole template. Select representative URLs across device, traffic, content, and template states, run the audit for each, and compare available URL-level or origin-level CrUX coverage separately.

Needs more evidence

## Use the audit with an agent or in code

The command above is enough for most work. These options let an agent, script or application run the same audit with explicit input and structured output.

### CLI

Use the report catalog when an agent, script or CI job needs predictable JSON instead of the normal terminal output. Check the current input first, then run the audit with the validated parameters.

Check the current input before the agent or script runs the audit.

```
seo reports describe performance-audit --json
```

Once the input is valid, run the audit through the report catalog.

```
seo reports run performance-audit --params '{"url":"https://example.com/","strategy":"mobile","refresh":true}' --json
```

### MCP

An MCP agent follows the same two-step flow. It inspects the current schema, fills the required fields and only then runs the audit.

Ask the MCP server for the current audit input.

```
{
  "id": "performance-audit"
}
```

Run the audit after the agent has checked and filled the input.

```
{
  "id": "performance-audit",
  "params": {
    "url": "https://example.com/",
    "strategy": "mobile",
    "refresh": true
  }
}
```

### TypeScript

Install the package in a Node 22 project when your application needs to run the audit directly. The result includes the same evidence, warnings and limits returned through the CLI and MCP server.

Add the SEO package to your project.

```
npm install seo
```

Run the audit from your TypeScript application.

```
import { executeReport } from 'seo/mcp'

const result = await executeReport(
  'performance-audit',
  {
  "url": "https://example.com/",
  "strategy": "mobile",
  "refresh": true
},
)

console.log(result)
```

## What to do next

Start with the highest-impact problem supported by the lab trace and test the fix on the same page and device profile. Rerun Lighthouse immediately, then wait for field data before claiming a Core Web Vitals improvement.

1.  01Fix the returned bottleneck with the strongest evidence and rerun under the same conditions.
2.  02Check representative templates rather than assuming one page describes the whole site.

## Related reports

[

Audit one URL for technical SEO, metadata, canonicals, schema, links and Search Console queries. See the live evidence before changing the page.

SEO page audit

](https://seoskill.dev/docs/reports/audit-page)[

Check sitemap URL status, redirects and access first. Run the full technical SEO crawl only when you need page content, links, metadata and affected URLs.

Sitemap health check and technical site crawl

](https://seoskill.dev/docs/reports/site-crawl)[

Compare matched Search Console periods around a recorded SEO change and keep releases, demand shifts and other confounders beside the result.

SEO change measurement

](https://seoskill.dev/docs/reports/measure-change)

## Sources used by this audit

These primary sources define the provider data or search controls used by the result.

-   [Core Web Vitals metrics and thresholds](https://web.dev/articles/vitals)