MCP Inspector
by Model Context Protocol
The visual testing and debugging tool for MCP servers.
Overview
The MCP Inspector is the official visual testing tool for MCP servers. It comprises the MCP Inspector Client (MCPI), a React-based web UI for interactive testing and debugging, and the MCP Proxy (MCPP), a Node.js server that bridges the web UI to MCP servers over stdio, SSE, or streamable-http transports. You can launch it with a single command (npx @modelcontextprotocol/inspector) to open a browser interface, or use it in CLI mode for scripting and automation, or via Docker. It lets you browse the tools, resources, and prompts a server exposes, invoke them interactively, and read a live log of every request, response, notification, and error exchanged with your server, with support for config files and bearer-token authentication.
At a Glance
- Topic
- MCP
- Level
- Intermediate
- Format
- Interactive
- Cost
- Free
- Provider
- Model Context Protocol
- Hands-on
- Yes — code/exercises
- Certificate
- None
What You’ll Learn
- ✓How to inspect the tools, resources, and prompts a server exposes
- ✓Interactively invoking server capabilities and reading responses
- ✓Debugging via the live message/notification/error log
- ✓Using UI, CLI, and Docker modes for different workflows
Highlights
- •Official first-party debugging tool for MCP servers
- •Runs instantly via npx, no install
- •UI and CLI modes for both exploration and automation
Who It’s For
Best For
- ✓Developers building and debugging MCP servers
- ✓Teams validating server behavior before shipping
Prerequisites
- •A running MCP server to inspect
- •Node.js and basic command-line familiarity
FAQ
What is MCP Inspector?
An interactive, browser-based developer tool for testing and debugging MCP servers. For anyone building an MCP server who wants to inspect its tools, resources, and prompts and watch live protocol messages.
Is MCP Inspector free?
MCP Inspector is free to access.
What level is MCP Inspector for?
MCP Inspector is aimed at a intermediate audience. Recommended background: A running MCP server to inspect, Node.js and basic command-line familiarity.
What will I learn from MCP Inspector?
You'll learn: How to inspect the tools, resources, and prompts a server exposes; Interactively invoking server capabilities and reading responses; Debugging via the live message/notification/error log; Using UI, CLI, and Docker modes for different workflows.