Attest

npm version npm downloads License: MIT Node.js

Trust scanning for agent payments — right inside your AI agent.

attest-mcp is a Model Context Protocol server that lets any MCP-compatible agent (Claude, Cursor, Windsurf, VS Code, and more) scan an agent payment endpoint and get back a letter grade A–F with a clear safety verdict before authorizing a single cent.

It covers the agentic payment protocols in use today: x402, MPP, AP2, L402, and HTTP 402.

Powered by Attest. The scoring engine runs entirely on Attest's servers — this package is a thin client that relays requests, so installing it never exposes any proprietary grading logic.

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Why

Autonomous agents are starting to pay for things on their own. A single malicious or misconfigured endpoint can drain funds through impersonation, a blocklisted payout wallet, bait-and-switch pricing, or a broken payment handshake. attest-mcp gives your agent a fast, deterministic safety check it can run as a step in its payment loop.

Tools

Tool	What it does
attest_scan	Runs a full scan on a payment endpoint URL and returns a grade (A–F), a composite score (0–100), a verdict, danger flags, price, and a link to the full report. Call this before paying an unfamiliar endpoint.
attest_grade	Fast lookup of the most recent grade for a host that has already been scanned. Good for a quick pre-check.

Requirements

• Node.js 18 or newer
• Any MCP-compatible client

No API key required.

Quick start

Run it directly with npx (no install needed):

npx attest-mcp

The server speaks MCP over stdio, so you normally don't run it by hand — you point your MCP client at it using one of the configs below.

Client setup

Claude Desktop

Edit claude_desktop_config.json (Settings → Developer → Edit Config):

{
  "mcpServers": {
    "attest": {
      "command": "npx",
      "args": ["-y", "attest-mcp"]
    }
  }
}

Cursor

Add to ~/.cursor/mcp.json (or Settings → MCP → Add new server):

{
  "mcpServers": {
    "attest": {
      "command": "npx",
      "args": ["-y", "attest-mcp"]
    }
  }
}

Windsurf

Add to ~/.codeium/windsurf/mcp_config.json:

{
  "mcpServers": {
    "attest": {
      "command": "npx",
      "args": ["-y", "attest-mcp"]
    }
  }
}

VS Code

Add to .vscode/mcp.json in your workspace:

{
  "servers": {
    "attest": {
      "command": "npx",
      "args": ["-y", "attest-mcp"]
    }
  }
}

Any other MCP client

Use the command npx -y attest-mcp with the stdio transport.

Remote server (no install)

Prefer not to install anything? Attest also runs a hosted MCP server you can connect to over Streamable HTTP:

https://attestagent.org/api/mcp

Point any remote-MCP-capable client at that URL.

Usage example

Once connected, just ask your agent in natural language:

"Before you pay, scan https://api.example.com/paid-resource with Attest."

The agent calls attest_scan and gets back something like:

{
  "host": "api.example.com",
  "grade": "A",
  "composite": 95,
  "danger": false,
  "verdict": "Valid endpoint, established host.",
  "priceHuman": "0.01 USDC",
  "reportUrl": "https://attestagent.org/r/abc-123"
}

Configuration

Environment variable	Default	Description
ATTEST_BASE_URL	https://attestagent.org	Override the Attest API base URL. Only needed for self-hosting or testing.

Security & privacy

• No secrets, no accounts, no API keys. The server holds no credentials.
• No proprietary logic ships here. Grading happens server-side; this package only relays requests and formats responses.
• Inputs are validated before any request is made.
• Outbound only. The server makes HTTPS requests to the Attest API and speaks MCP over stdio — it opens no inbound ports.
• Scanned URLs and results are logged to Attest's public directory. Do not scan endpoints whose URL or response contains private or sensitive information. See attestagent.org/legal.

Links

• Website: attestagent.org
• Developer docs: attestagent.org/developers
• Methodology: attestagent.org/methodology
• X / Twitter: @Attestagent

Contributing

Issues and pull requests are welcome — see CONTRIBUTING.md.

License

MIT © Attest