macOS Defaults MCP server

This MCP server provides a streamlined way to read and write macOS defaults (system settings) using the Model Context Protocol. It wraps the macOS defaults command, allowing Claude and other MCP-compatible applications to interact with your system preferences.

Installation

For Claude Desktop

You need to modify the Claude Desktop configuration file to add the MCP server:

• On MacOS: ~/Library/Application\ Support/Claude/claude_desktop_config.json
• On Windows: %APPDATA%/Claude/claude_desktop_config.json

Add the following to your configuration file:

If you have the repository downloaded:

"mcpServers": {
  "mcp-server-macos-defaults": {
    "command": "uv",
    "args": [
      "--directory",
      "/path/to/mcp-server-macos-defaults",
      "run",
      "mcp-server-macos-defaults"
    ]
  }
}

If you want to use the published package:

"mcpServers": {
  "mcp-server-macos-defaults": {
    "command": "uvx",
    "args": [
      "mcp-server-macos-defaults"
    ]
  }
}

Usage

The MCP server provides several commands to interact with macOS defaults:

List Domains

Lists all available defaults domains (equivalent to defaults domains):

list-domains

Find Settings

Searches for settings containing a specific word (equivalent to defaults find <word>):

find <search-term>

Read Defaults

Reads the value of a specific setting (equivalent to defaults read <domain> <key>):

defaults-read <domain> [key]

If the key is not provided, the entire domain's settings will be read.

Write Defaults

Modifies a specific setting (equivalent to defaults write <domain> <key> <value>):

defaults-write <domain> <key> <value>

Troubleshooting

If you encounter issues, you can use the MCP Inspector for debugging. The inspector allows you to see the communication between Claude and the MCP server, which can help identify problems.

Access the MCP Inspector through your browser after launching it with the following command:

npx @modelcontextprotocol/inspector uv --directory /path/to/mcp-server-macos-defaults run mcp-server-macos-defaults

How to install this MCP server

For Claude Code

To add this MCP server to Claude Code, run this command in your terminal:

claude mcp add-json "mcp-server-macos-defaults" '{"command":"uvx","args":["mcp-server-macos-defaults"]}'

See the official Claude Code MCP documentation for more details.

For Cursor

There are two ways to add an MCP server to Cursor. The most common way is to add the server globally in the ~/.cursor/mcp.json file so that it is available in all of your projects.

If you only need the server in a single project, you can add it to the project instead by creating or adding it to the .cursor/mcp.json file.

Adding an MCP server to Cursor globally

To add a global MCP server go to Cursor Settings > Tools & Integrations and click "New MCP Server".

When you click that button the ~/.cursor/mcp.json file will be opened and you can add your server like this:

{
    "mcpServers": {
        "mcp-server-macos-defaults": {
            "command": "uvx",
            "args": [
                "mcp-server-macos-defaults"
            ]
        }
    }
}

Adding an MCP server to a project

To add an MCP server to a project you can create a new .cursor/mcp.json file or add it to the existing one. This will look exactly the same as the global MCP server example above.

How to use the MCP server

Once the server is installed, you might need to head back to Settings > MCP and click the refresh button.

The Cursor agent will then be able to see the available tools the added MCP server has available and will call them when it needs to.

You can also explicitly ask the agent to use the tool by mentioning the tool name and describing what the function does.

For Claude Desktop

To add this MCP server to Claude Desktop:

1. Find your configuration file:

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

2. Add this to your configuration file:

{
    "mcpServers": {
        "mcp-server-macos-defaults": {
            "command": "uvx",
            "args": [
                "mcp-server-macos-defaults"
            ]
        }
    }
}

3. Restart Claude Desktop for the changes to take effect