Configuring MCP Server in Cursor

In the previous chapters, we successfully created an MCP Server. Now, we need to tell Cursor how to find and use this server. This is done through a configuration file.

Creating the Configuration File

1. First, open any project in Cursor (it can be a new project or an existing one).

2. Create a .cursor folder in the project root (if it doesn’t exist):

   mkdir .cursor

3. Create an mcp.json file in the .cursor folder:

   touch .cursor/mcp.json

4. Add the following configuration to the mcp.json file:

   {
       "mcpServers": {
           "about-me": {
               "command": "uv",
               "args": [
                   "--directory",
                   "/Users/{your_username}/Code/Playground/build_mcp_for_cursor/project",
                   "run",
                   "main.py"
               ]
           }
       }
   }

Understanding the Configuration

Let’s break down each part of this configuration file:

1. mcpServers

   • This is the main section that defines all MCP servers

2. about-me

   • This is our server name, which must match the name in FastMCP("about-me")
   • You can change this name, but ensure it matches in both places

3. command

   • Specifies which command to use to run the server
   • We’re using uv, our package manager

4. args

   • List of command arguments, including:
     • --directory: Specifies the project directory
     • Project path: You need to replace this with your actual project path
     • run: The uv run command
     • main.py: The Python file to run

Enabling the MCP Service

After creating the configuration file, we need to enable the service in Cursor:

1. Open Cursor Settings

   • Windows/Linux: Click the gear icon in the bottom left or use Ctrl + ,
   • macOS: Click the gear icon in the bottom left or use Cmd + ,

2. In the Settings panel:

   • Find and click “MCP” in the left sidebar
   • You should see our “about-me” service
   • Click the “Enabled” option to enable the service

Verifying the Service

Now we can test if our service is working:

1. Open Cursor’s Agent mode

   • Click the AI icon in the sidebar
   • Or use the keyboard shortcut to open the AI panel

2. Try these test questions:

   Q: What's my name?
   A: [AI will call get_user_name() and return "Lucas Lee"]
   
   Q: How old am I?
   A: [AI will call get_user_age() and return 30]

If you receive the correct answers, congratulations! Your MCP Server is configured and working properly!

Common Issues

1. Can’t Find MCP Settings?

   • Ensure your Cursor is up to date
   • Try restarting Cursor IDE

2. Service Appears Grayed Out?

   • Check if the configuration file format is correct
   • Ensure the project path is correct and accessible

3. Agent Can’t Get Information?

   • Make sure the service is properly enabled
   • Check if the Python service is running
   • Look at Cursor’s log information

Next Steps

Now that you’ve successfully configured and tested your MCP Server, you can:

• Add more custom tools
• Modify the returned information
• Implement more complex functionality
• Explore other possibilities with MCP servers