MCP Inspector — MCP protocol

Official developer tool for testing and debugging MCP servers

Basic Information

What Is This Program?

MCP Inspector is the official developer tool for testing and debugging MCP (Model Context Protocol) servers. It consists of a React-based web UI and a Node.js proxy, and contains three clients in a single package (@modelcontextprotocol/inspector).

You can visually inspect the tools, resources, and prompts exposed by a server and view request and response messages in real time. It is the first tool to launch when building an MCP server or connecting to an existing one.

What Problems Does It Solve?

• When you need to verify that a newly built MCP server works correctly
• When you need to find the cause of MCP server connection failures from a client
• When you need to compare different transport methods such as stdio and HTTP in the same environment

Key Features

Web UI

Visually browse tools, resources, and prompts in the browser

• When to Use: Get an overview of server capabilities at a glance
• What You Get: Invoke tools and check results without typing
• Limitations: Large responses may require scrolling

Multi-Transport Support

Supports stdio, SSE, and Streamable HTTP transports

• When to Use: Debugging all types of MCP servers
• What You Get: Compare behavior across transport methods
• Limitations: Authentication settings differ slightly by transport

Real-Time Monitoring

Displays protocol traffic in the sidebar in real time

• When to Use: Trace request and response flows
• What You Get: Detailed logs for debugging
• Limitations: Filtering is needed when there are many logs

Export Configuration

Export the server launch configuration to mcp.json

• When to Use: Share client configurations
• What You Get: A reproducible debugging environment setup
• Limitations: Check for format differences between clients

Installation and Execution

npx (Recommended)

Runs immediately with npx without separate installation.

npx @modelcontextprotocol/inspector

npm Global Installation

If you use it frequently, install it globally.

npm install -g @modelcontextprotocol/inspector

Docker

Run it in an isolated container.

docker run -p 5173:5173 -p 8080:8080 mcp/inspector

Practical Usage Examples

Connecting to a Server

Run Inspector and enter the MCP server command to connect.

npx @modelcontextprotocol/inspector npx -y @modelcontextprotocol/server-filesystem /tmp

Invoking a Tool

On the Tools tab, select a tool, enter its arguments, and run it.

Example: enter a path in the read_file tool and click Run

Reviewing Traffic

Check request and response messages in the Monitoring sidebar.

Check STDIO · SSE · HTTP logs in real time

Advantages and Limitations

Advantages

• A highly reliable tool maintained by the official MCP project
• Supports stdio, SSE, and HTTP transports in a single UI
• Runs immediately with npx without separate installation
• Visually traces request and response traffic

Considerations Before Use

• Debugging the server-side logic itself requires a separate tool
• Browsing large tool lists can be somewhat slow
• OAuth authentication flows require additional setup

Comparison with Similar Programs

Official Resources and Further Learning

• Official Homepage — https://modelcontextprotocol.io/docs/tools/inspector
• Official Documentation / Knowledge Base — https://modelcontextprotocol.io/docs/tools/inspector
• Installation & Distribution — npx @modelcontextprotocol/inspector
• Release Notes — https://github.com/modelcontextprotocol/inspector/releases
• Source / Development Materials — https://github.com/modelcontextprotocol/inspector

Version and supported environment information was confirmed on the official site as of 2026-10-18. Installation commands may vary depending on your distribution and version, so please also check the official installation documentation.

Actual Execution Screenshot

Synthetic example — not an actual execution result. The screenshot is a synthetic example and is not an actual execution result.

!Example MCP Inspector execution screen

A server in actual operation

Source (HTML): https://games.aidebatehub.com/programs/mcp/protocol/inspector.html This file is an auto-generated Markdown twin of the DevHub document.