Name: Guardbee
Brand: Guardbee
Availability: InStock

MCP guide · Rug Pull Detector

MCP Rug Pull Detector: catch silent tools/list drift — @guardbee/mcp-rug-pull-detector

@guardbee/mcp-rug-pull-detector does not read source — it is a real MCP client. It connects over stdio or Streamable HTTP, calls tools/list, and stores a trust-on-first-use baseline.

What does it do?

baseline_server stores a canonical hash + snapshot; check_server re-fetches later. Changed existing tool definitions are critical (the rug pull); new tools medium; removed tools low.

Who is it for?

Teams that run third-party MCP servers
Security teams verifying tool definitions before each session
Anyone loading servers from a Claude Desktop-style config

What it is not

Description injection in source (use Tool Poisoning Scanner)
Handler sink scanning (use Server Auditor)
Unauthorized probing of servers you do not own

Features

Feature	Description
Real MCP client	stdio + Streamable HTTP
Canonical hash	description + schema + annotations
Claude Desktop config	–config + –server
SARIF 2.1.0	CI / schedules
Auto-baseline	check_server can write the first baseline

MCP tools

Tool	Description
`baseline_server`	Store the first tools/list snapshot
`check_server`	Diff against the stored baseline
`list_baselines`	List stored baselines

Install with npm

Global install (handy for Claude Desktop / Cursor):

bash

npm install -g @guardbee/mcp-rug-pull-detector

or via npx (recommended with -y in config):

bash

npx -y @guardbee/mcp-rug-pull-detector

npm: @guardbee/mcp-rug-pull-detector

CLI

npx @guardbee/mcp-rug-pull-detector baseline --config=claude_desktop_config.json --server=some-server

then check --fail-on=critical.

Claude Desktop configuration

Config file paths:

macOS~/Library/Application Support/Claude/claude_desktop_config.json
Windows%APPDATA%\Claude\claude_desktop_config.json
Linux~/.config/Claude/claude_desktop_config.json

Merge this block, then restart Claude Desktop:

claude_desktop_config.json

{
  "mcpServers": {
    "guardbee-rug-pull-detector": {
      "command": "npx",
      "args": [
        "-y",
        "@guardbee/mcp-rug-pull-detector"
      ]
    }
  }
}

Cursor and other MCP clients

In Cursor, add the same command / args / env under Settings → MCP. stdio MCP servers use the same contract as Claude Desktop.

Example prompts in Claude

“Baseline this MCP server”
“Before we use it today, check tools/list for drift”
“Which servers have I baselined?”

See surface risk with Guardbee

MCP servers speed up security work in chat. Start a 14-day free trial for brand scans and BeeAI.

Start free MCP servers

Frequently asked questions

Vs static scanners?

A server can change tools/list at request time without changing source — only a live client sees that.

API key?

No — you connect to the target server yourself.

Are new tools critical?

No — medium; changing an existing tool definition is critical.

MCP Rug Pull Detector: catch silent tools/list drift