WebPerf Snippets MCP server
io.github.nucliweb/webperf-snippets·v1.10.0·1.5k starsMeasure Core Web Vitals and debug web performance with 56 snippets in a headless Chromium
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1.5k stars630 downloads/wk
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If you have run it, two minutes of your experience saves the next person an afternoon.
WebPerf Snippets tools
No tool declarations could be read from the package source. They show once the server is installed.
How WebPerf Snippets compares
Against every graded MCP server, from our own scans and uptime checks. Updated after each scan run.
- Safety score
- 83/100
- higher than 65% of 48,273 servers
- GitHub stars
- 1,455
- more than 95% of 28,534 servers
- Downloads a week
- 630
- more than 91% of 11,915 servers with a package
Release history: 9 versions in the registry since 2026-10-22, latest 2026-11-01, typically one every 1 day.
Install WebPerf Snippets in Claude Code, Cursor or VS Code
Runs npx -y webperf-snippets on your machine. Read the scan report first; the gateway never runs local packages.
claude mcp add webperf-snippets -- npx -y webperf-snippets
What the publisher says
From the WebPerf Snippets repository's README, as published. We do not edit it. Read it on GitHub
WebPerf Snippets
Tested JavaScript snippets that measure and debug web performance. Your AI agent runs them for you, or you run them yourself in DevTools: the same code every time.
AI agents are good at interpreting performance data and unreliable when they write measurement code on the fly. WebPerf Snippets keeps both apart: the measurement is fixed code, tested in CI, that returns structured data, and the agent reasons about the result. The same snippets run in the console, the CLI, the DevTools extension and the Agent Skills, and every one returns an object that follows a single contract (snippets/SCHEMA.md).
→ Why AI audits need deterministic scripts
Run them with an AI agent
Not sure which snippet to run? Start from the symptom in Which snippet should I use?
Copy prompt
Snippet pages have a Copy prompt button above the code. It copies a prompt that asks any AI agent with a terminal to run that snippet with the CLI on the URL you give it, and to report the value, the cause and the issues. The agent runs the published snippet instead of rewriting it or estimating the result.
MCP server
The CLI includes an MCP server: an agent in any MCP client (Claude Code, Cursor, VS Code, Gemini CLI) calls the snippets and the workflows as tools, on a headless Chromium, and reads the object each one returns. It is listed in the MCP Registry as io.github.nucliweb/webperf-snippets.
claude mcp add webperf -- npx -y webperf-snippets mcpIn Claude Code, the webperf plugin installs the same server:
/plugin install webperf --marketplace nucliweb/webperf-snippetsSee the MCP server documentation for other clients, the tools, the resources and prompts, and the CrUX key.
Agent skills
The snippets are packaged as Agent Skills for Claude Code, Cursor, OpenCode, Gemini CLI, VS Code extensions and other compatible agents. With Chrome DevTools MCP, the agent runs the snippets in your browser and reads the object they return.
Shortened. The full README is on GitHub.
Nothing above is checked by us. What we check is on the safety report.
WebPerf Snippets: common questions
- Is WebPerf Snippets MCP server safe?
- Mostly: it is graded B (83/100). Read the WebPerf Snippets safety report
- How do I install WebPerf Snippets?
- It runs on your machine. Copy the Claude Code, Cursor, VS Code or Claude Desktop config from the install section.
- Does WebPerf Snippets need an API key?
- Yes. The registry entry asks for
CRUX_API_KEY. - Is WebPerf Snippets maintained?
- The last commit was 9 days ago (2026-10-24). The latest release is v1.10.0.
- How does WebPerf Snippets compare with other MCP servers?
- safety score 83/100 (higher than 65% of 48,273 servers); github stars 1,455 (more than 95% of 28,534 servers); downloads a week 630 (more than 91% of 11,915 servers with a package). Full comparison.