@mcpjam/inspector NPM

MCPJam Inspector

The developer tool for testing and debugging MCP servers

Quick Start

Get up and running in seconds with the MCPJam Inspector:

npx @mcpjam/inspector@latest

That's it! The inspector will launch automatically in your browser at http://localhost:6274.

📸 Screenshots

✨ Core Features

This project is a fork of the @modelcontextprotocol/inspector. Many of the features are the same but with some enhancements. Key features include:

STDIO / SSE / Streamable HTTP - This inspector supports all three protocols. Connect to any MCP server.
Tool Execution - Run server tools with live parameter input. Easily debug errors.
(New) LLM tool interaction - Test your MCP server against a real LLM.
Debugging tools - Enhanced logging experience to debug your server.
Quality of life improvements - Save requests, multi-server connection, saved connections.

📋 Requirements

Node.js: ^22.7.5 or higher
npm: ^10.0.0 or higher (comes with Node.js)

🎯 Usage Examples

Basic Usage

# Launch inspector with default settings
npx @mcpjam/inspector

Connect to Local Server

# Connect to a server built at build/index.js
npx @mcpjam/inspector node build/index.js

Connect with Arguments

# Pass custom arguments to your server
npx @mcpjam/inspector node server.js --port 3000 --debug

Using Configuration File

# Load servers from a config file
npx @mcpjam/inspector --config ./my-config.json

Example Configuration File

{
  "mcpServers": {
    "my-awesome-server": {
      "command": "node",
      "args": ["build/index.js"],
      "env": {
        "API_KEY": "your-api-key",
        "DEBUG": "true"
      }
    },
    "python-server": {
      "command": "python",
      "args": ["-m", "my_mcp_server"],
      "env": {
        "PYTHONPATH": "./src"
      }
    }
  }
}

🏗️ Architecture

The MCPJam Inspector is built as a modern monorepo with three main components:

📦 @mcpjam/inspector
├── 🖥️  client/     # React + TypeScript frontend
├── 🔧  server/     # Express.js backend with WebSocket support
└── 🚀  cli/        # Command-line interface

Tech Stack

Frontend: React 18, TypeScript, Tailwind CSS, Radix UI
Backend: Express.js, WebSocket (ws), CORS support
CLI: Node.js with shell integration
Build Tools: Vite, TSC, Concurrently

🛠️ Development

Local Development Setup

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

# Install dependencies
npm install

# Start development servers
npm run dev

Build for Production

# Build all components
npm run build

# Test the build
npm run start

Scripts for development

We put together these commands to help you build locally: | Script | Description | | ---------------------- | ------------------------------------------- | | npm run dev | Start development servers (client + server) | | npm run build | Build all components for production | | npm run test | Run test suite | | npm run prettier-fix | Format code with Prettier | | npm run clean | Clean all build artifacts and reinstall |