Lettersby Letter

MCP

First-class MCP

Tools: send_letter, get_letter_status, list_jobs, get_pricing. Create an API key in the Developers page, then drop one of these configs into your client.

Cursor

mcp.json

{
  "mcpServers": {
    "lettersbyletter": {
      "command": "node",
      "args": ["./scripts/mcp-server.mjs"],
      "env": {
        "LETTERSBYLETTER_API_URL": "http://127.0.0.1:43127",
        "LETTERSBYLETTER_API_KEY": "lbl_your_key"
      }
    }
  }
}

Claude Desktop

Place this in claude_desktop_config.json.

claude_desktop_config.json

{
  "mcpServers": {
    "lettersbyletter": {
      "command": "node",
      "args": ["/absolute/path/to/lettersbyletter/scripts/mcp-server.mjs"],
      "env": {
        "LETTERSBYLETTER_API_URL": "https://lettersbyletter.com",
        "LETTERSBYLETTER_API_KEY": "lbl_your_key"
      }
    }
  }
}

HTTP transport

JSON-RPC POST to /api/mcp with a Bearer key.

HTTP MCP

{
  "mcpServers": {
    "lettersbyletter": {
      "url": "https://lettersbyletter.com/api/mcp",
      "headers": {
        "Authorization": "Bearer lbl_your_key"
      }
    }
  }
}