@mcp-devtools/lighthouse

MCP server — run Lighthouse audits and get performance scores, Core Web Vitals, and actionable opportunities.

Install

npm install -g @mcp-devtools/lighthouse
npx playwright install chromium   # one-time ~280MB download

Add to Claude Desktop

~/Library/Application Support/Claude/claude_desktop_config.json:

{
  "mcpServers": {
    "lighthouse": {
      "command": "mcp-lighthouse"
    }
  }
}

Restart Claude Desktop after editing the config.

Tools

audit_lighthouse

Run a full Google Lighthouse audit on any URL. Works with localhost, staging, and production.

url: string           — URL to audit. E.g. https://example.com or http://localhost:3000
categories?: string[] — 'performance', 'accessibility', 'best-practices', 'seo'. Default: all four
mobile?: boolean      — Simulate mobile with network/CPU throttling. Default: false (desktop)
timeout?: number      — Max audit time in ms. Default: 60000 (60s)

Returns category scores (0–100), Core Web Vitals (LCP, FCP, TBT, CLS, TTI, Speed Index) with ratings, performance opportunities with estimated savings, and all failing audits.

Docker / CI: Set LIGHTHOUSE_NO_SANDBOX=1 env var when running in a sandboxed environment.

compare_lighthouse

Compare Lighthouse scores between two URLs. Runs a full audit on both and returns a side-by-side diff.

before_url: string  — Baseline URL (staging branch, old deploy)
after_url: string   — New URL (optimized deploy, new branch)
mobile?: boolean    — Run in mobile mode. Default: false (desktop)

Example prompts

"Run a Lighthouse audit on http://localhost:3000"

"What's the LCP on my homepage and how can I improve it?"

"Run a mobile performance audit on my product page"

"Compare performance scores between my staging and production URLs"

"Which SEO issues is Lighthouse flagging on my site?"

Development

npm install
npx playwright install chromium
npm run build
npm run dev

License

MIT

track_lighthouse

Run a Lighthouse audit and store the result for trend tracking. Each run saves scores and Core Web Vitals to ~/.mcp-lighthouse/history.json.

url: string     — URL to audit and track
mobile?: boolean — Desktop or mobile. Default: desktop

Returns the current scores with ↑/↓/→ trend indicator vs the previous run.

get_lighthouse_trend

Show the full score history for a previously tracked URL.

url: string      — URL to show history for
mobile?: boolean — Desktop or mobile history. Default: desktop
limit?: number   — Max entries to show. Default: 10

Returns a table of scores over time and a trend summary (improving / degrading / stable). History stored at ~/.mcp-lighthouse/history.json, up to 50 audits per URL.

Example prompts (trend tracking)

"Track the Lighthouse performance score for https://example.com over time"

"Show the performance trend for my staging URL over the last 10 audits"

"Has my homepage performance improved after today's deploy?"