Install Letterbox for Claude Desktop

Claude Desktop reads mcpServers from claude_desktop_config.json. Restart the app after saving.

Open ~/Library/Application Support/Claude/claude_desktop_config.json on macOS, %APPDATA%\Claude\claude_desktop_config.json on Windows, or ~/.config/Claude/claude_desktop_config.json on Linux.
Paste the JSON config below.
Replace placeholder secrets, then restart the client if it does not reload on its own.

~/Library/Application Support/Claude/claude_desktop_config.json

{
  "mcpServers": {
    "dovahkiin-v-letterbox": {
      "command": "uvx",
      "args": [
        "letterbox"
      ],
      "env": {
        "LETTERBOX_CHANNEL": "",
        "LETTERBOX_SENDER": "",
        "LETTERBOX_INSTANCE_ID": ""
      }
    }
  }
}

Official Claude Desktop docs

Install Letterbox for Claude Desktop | MCPpedia