In yesterday’s post I wrote about how I thought Model Context Protocol (MCP) was one of the most interesting aspects of the current AI hype. I’m going to start writing about an MCP server that I am building, but before I start that I thought I would talk about a tool which is a great help in building and testing MCP servers, and that tool is MCP Inspector.

MCP Inspector will act as a client for your MCP server, similar to Postman or the Swagger UI, the MCP Inspector lets you connect to your MCP server, examing and validate it’s output, and use the various tools the server exposes. For MCP servers that run as subprocesses listening over stdin, MCP Inspector will even run the subprocess for you.

MCP Inspector is also up to date with the latest MCP features as it is an open source project run by Anthropic, who were the originators of the MCP specification. To run MCP Inspector you need to do the following:

1. Install node. (On my Mac I used homebrew to install node with the command brew install node.)
2. Download and run MCP Inspector with the command npx @modelcontextprotocol/inspector.

That’s it. Now you can start testing MCP servers with impunity.