vibecheck-mcp

Audit your local dev server with Claude. Drop one .mcp.json into any project and call audit_dev_server() to get a full performance report — Vibe-Score, ranked findings, and actionable recommendations — without leaving your editor.

Powered by VibeCheck Ultra.

Requirements

• Node.js 20+
• Playwright Chromium (one-time install):

  npx playwright install chromium

Setup

Add .mcp.json to your project root:

{
  "mcpServers": {
    "vibecheck": {
      "command": "npx",
      "args": ["@roeeash/vibecheck-mcp@latest"],
      "env": {
        "DEV_PORT": "5173"
      }
    }
  }
}

Change DEV_PORT to match your dev server's port if it isn't 5173.

Open the project in Claude Code — the MCP server loads automatically. Start your dev server, then run:

ToolSearch select:vibecheck

This is because vibecheck is a deferred tool. Before calling it, Claude must load its schema via ToolSearch.

Then, run:

vibecheck

Tools

| Tool | Description | |---|---| | vibecheck | Audit your dev server. Starts the audit API automatically and returns a full report. |

What Gets Audited

VibeCheck runs a headless Chromium browser against your dev server and reports on:

• Web Vitals — LCP, CLS, INP, FCP with reproduction traces
• Network — N+1 chains, waterfalls, duplicate fetches, missing cache headers
• Assets — oversized images, render-blocking scripts, unused CSS, bloated JS bundles
• Render — React re-render storms, missing memoization, unvirtualized lists
• Memory — leaked intervals, detached listeners, unbounded state growth

Every finding includes what was observed, where, confidence level, and a specific recommendation.