Set Up Your First MCP Server in 5 Minutes

This guide walks you through installing your first MCP server (the Filesystem server) and connecting it to Claude Desktop, turning a standard LLM chat interface into a capable local coding assistant.

Prerequisites

• ▸Node.js 18+ installed on your system (node -v to check)
• ▸Claude Desktop application (download from anthropic.com)
• ▸Basic familiarity with your operating system's terminal or command line.

Step 1: Install Claude Desktop

Download and install Claude Desktop from the official Anthropic website. This will act as your MCP host — the application that connects to and coordinates your MCP servers.

Step 2: Locate Your Configuration File

Claude Desktop stores its MCP connection string configuration in a JSON file:

• ▸macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
• ▸Windows: %APPDATA%\Claude\claude_desktop_config.json

Create this file if it doesn't already exist.

Step 3: Add Your First Server

Let's start with the official filesystem MCP server. Edit your config file:

{
  "mcpServers": {
    "filesystem": {
      "command": "npx",
      "args": [
        "-y",
        "@modelcontextprotocol/server-filesystem",
        "C:/Users/yourusername/Documents/sandbox"
      ]
    }
  }
}

Best Practices

[!WARNING] Replace C:/Users/yourusername/Documents/sandbox with a real, absolute path on your system. Always use forward slashes / even on Windows paths. Backslashes \ act as escape characters in JSON and will silently corrupt your file paths.

• ▸Sandbox Your Environments: For your first server, point the path to an empty directory or a safe "sandbox" project. Do not point it to your root drive C:/.

Step 4: Restart Claude Desktop & Test

1. ▸Quit Claude Desktop completely (do not just close the window; right-click and exit the application from the system tray or macOS menu bar).
2. ▸Relaunch Claude Desktop.
3. ▸Look at the chat input box. You should now see a Hammer icon (🔨) in the bottom-right corner. Hovering over it will list the tools exposed by the filesystem server: read_file, write_file, list_directory, etc.
4. ▸Try asking Claude:

   "List the files inside my configured sandbox folder and write a hello.txt file inside it."

Troubleshooting Guide

If the Hammer icon does not appear, check the local logs generated by the host:

• ▸Windows: %APPDATA%\Claude\logs\mcp.log
• ▸macOS: ~/Library/Logs/Claude/mcp.log

Common Error: command not found: npx

This means Node.js is not added to your system $PATH, or Claude Desktop was launched in an environment where it couldn't inherit your user's path. Specify the absolute path to your npx.cmd (Windows) or npx (macOS/Linux) binary inside the "command" property.

Common Error: Invalid JSON Format

Ensure your JSON contains matching double quotes and no trailing commas. Even a single syntax error in claude_desktop_config.json will cause Claude to ignore the entire file silently. Validate your config via any online JSON parser.