Are you all enjoying using MCP (Model Context Protocol), which allows Claude to use external tools directly? While desktop extensions that can be installed with a single click have recently started being supported, you often need to manually edit the claude_desktop_config.json file if you want to connect custom servers or useful tools yourself. I'd like to share a few common pitfalls for beginners and how to solve them.

The most common issue is the spawn npx ENOENT error. This happens because the Claude Desktop app fails to properly inherit system environment variables and can't find the npx command. Instead of just putting command as the npx in your config file, you can solve it cleanly by running which npx (macOS) or where npx (Windows) in your terminal and entering the absolute path to npx exactly. Similarly, when specifying local folders, you must use the full absolute path rather than relative paths like ./ to avoid errors.

For those just getting started, I recommend trying the Brave Search server for real-time internet search and the Filesystem server for reading and writing local files. Note that the official package name for Brave Search has recently changed to @brave/brave-search-mcp-server, so please add the new package instead of the old one as shown below. Once you fully restart the Claude app, you'll see the plug icon enabled in the bottom right corner. It’s not as difficult to set up as you might think, so definitely give it a try!