MCPJam Inspector

A developer tool for testing and debugging MCP servers, supporting STDIO, SSE, and Streamable HTTP protocols.

GitHub

www.mcpjam.com

npm version License: Apache 2.0 Discord

MCPJam inspector is the local-first development platform for MCP servers. Visually test your server's tools, resources, and prompts. Try your server against different models in the LLM playground. Now with support for OpenAI Apps SDK.

📸 Screenshots

🚀 Quick Start

Start up the MCPJam inspector:

npx @mcpjam/inspector@latest

Key Features

FeatureDescription
Protocol handshake testingVisually test your MCP server's tools, resources, prompts, elicitation, and OAuth 2. MCPJam is compliant with the latest MCP specs.
All transportsConnect to any MCP server. MCPJam inspector supports STDIO, SSE, and Streamable HTTP transports.
LLM PlaygroundIntegrated chat playground with OpenAI, Anthropic Claude, Google Gemini, and Ollama model support. Test how your MCP server would behave against an LLM
Test OAuthTest your server's OAuth and Dynamic Client Registration implementation.
View JSON-RPCView every JSON-RPC message sent over network. Provides granular observability and debugging.
MCP-UI and OpenAI Apps SDKTest your MCP server's implementation of MCP-UI or OpenAI Apps SDK

🎉 Now with OpenAI Apps SDK support!

Developing with Apps SDK is pretty restricted right now as it requires ChatGPT developer mode access and an OpenAI partner to approve access. We wanted to make that more accessible for developers today by putting it in an open source project, give y’all a head start.

Test your Apps SDK app with:

  • Tools tab. Deterministically call tools and view your UI
  • LLM playground to see your Apps SDK UI in a chat environment

The feature is in beta, and still needs polishing. Please report any bugs in the issues tab. We encourage the community to contibute!

Installation Guides

We recommend starting MCPJam inspector via npx:

npx @mcpjam/inspector@latest

or download the Mac / Windows desktop app on our site.

🐳 Docker

Run MCPJam Inspector using Docker:

# Run the latest version from Docker Hub
docker run -p 3001:3001 mcpjam/mcp-inspector:latest

# Or run in the background
docker run -d -p 3001:3001 --name mcp-inspector mcpjam/mcp-inspector:latest

The application will be available at http://localhost:3001.

Open commands

# Launch with custom port
npx @mcpjam/inspector@latest --port 4000

# Shortcut for starting MCPJam and an Ollama model
npx @mcpjam/inspector@latest --ollama llama3.2

# Local FastMCP STDIO example
npx @mcpjam/inspector@latest uv run fastmcp run /Users/matt8p/demo/src/server.py

# Local Node example
npx @mcpjam/inspector@latest npx -y /Users/matt8p/demo-ts/dist/index.js

Connecting to MCP servers

mcp.json

You can import your mcp.json MCP server configs from Claude Desktop and Cursor with the command:

npx @mcpjam/inspector@latest --config mcp.json

SSE / Streamable HTTP

Spin up the MCPJam inspector

npx @mcpjam/inspector@latest

In the UI "MCP Servers" tab, click add server, select HTTP, then paste in your server URL. Support for OAuth 2.0 testing.

Requirements

Node.js TypeScript

🛠️ Development

Local Development Setup

# Clone the repository
git clone https://github.com/mcpjam/inspector.git
cd inspector

# Install dependencies
npm install

# Start development server
npm run dev

The development server will start at http://localhost:6274 with hot reloading enabled.

Build for Production

# Build the application
npm run build

# Start production server
npm run start

🤝 Contributing

We welcome contributions to MCPJam Inspector V1! Please read our Contributing Guide for development guidelines and best practices.

📚 Resources

📄 License

This project is licensed under the Apache License 2.0 - see the LICENSE file for details.

MCPJam Inspector V1 • Built with Hono.js and ❤️ for the MCP community

🌐 Website • 📖 Docs • 🐛 Issues

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