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Muppet Kit

Muppet Kit

Local
github.com/muppet-devDeveloper Tools58Updated 57w ago
Repository

About Muppet Kit

Muppet Kit is a collection of tools for testing and debugging MCP servers. Its Inspector is a developer tool for exploring and tracing MCP server behavior, with optional AI assistance.

Key features

  1. 01Explorer for browsing server capabilities with AI help
  2. 02Playground for testing with different LLMs and configurations
  3. 03MCP Scan for finding vulnerabilities and security issues
  4. 04Tracing of requests and responses between client and server
  5. 05History of request and response records for the session

Use cases

  1. 01Debugging tool and resource behavior of an MCP server
  2. 02Comparing how different LLMs call the same MCP server
  3. 03Checking an MCP server for security issues before release

MCP support

The Inspector is aimed at MCP server development and is used to connect to, test and trace communication between MCP servers and clients.

#visual-testing#mcp-servers#testing-tool

Configuration

Local server config is the same for every client. Copy it into your client’s MCP config file.

mcp.json · Universal config
{
  "mcpServers": {
    "kit": {
      "command": "npx",
      "args": [
        "-y",
        "muppet-kit"
      ]
    }
  }
}
Run commandnpx -y muppet-kit

Local servers need a runtime on your machine (e.g. Node.js 18+). Config file locations differ by client; see your client’s docs.

Packages
npmmuppet-kit

Tools

No tool list yet

Local servers expose tools only once running on your machine, and the maintainer has not provided a tool list.

Details

From the project README

Muppet Kit

It is a collection of tools for testing and debugging MCPs.

Inspector

It is a devtool for testing and debugging MCPs servers.

Inspector

Deploy to Cloudflare

Usage
npx muppet-kit inspector
Features
  • Explorer - Explore the MCP server's capabilities, while leveraging AI to assist you.
  • Playground - Test the MCP server with different LLMs and configurations.
  • MCP Scan - Scan the MCP server for vulnerabilities and security issues.
  • Tracing - Trace the requests and responses between the client and server. Tunneling is also supported for connecting to remote clients.
  • History - View the history of requests and responses between the client and server for the current session.
Configuration

You can configure the inspector by creating a muppet.config.js/muppet.config.ts file in the root of your project. The configuration file should export an object with the following properties:

import { defineInspectorConfig } from "muppet-kit";
import { ngrok } from "muppet-kit/tunnel";
import { openai } from "@ai-sdk/openai";

export default defineInspectorConfig({
  // ...
  models: [openai("gpt-4.1-nano")],
  // You can either pass the API key here or have it in .env as NGROK_API_KEY
  tunneling: ngrok(),
});

Credits

The idea for this project was inspired by the official MCP Inspector and their amazing work.

Comments

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