Once MCP Server

What the code does

We read the source, 7 h ago · rules 3dff92dd89df

What this server is able to do. For an MCP server this is often the job itself — a terminal server runs commands because that is what it is for. Listed so you know what you are plugging in, not as an accusation.

    const child = spawn(

    path.join(
      onceDirectory,
      "backups",
      candidate.callsite_ref
    );

Is this your server and something here is wrong? Tell us — corrections are free and do not require a plan.

Connect this server

This server runs on your own machine — install it with the package manager and the client starts it for you. Package name taken from the official registry entry.

claude mcp add once -- npx -y @once-agent/mcp

{
  "mcpServers": {
    "once": {
      "args": [
        "-y",
        "@once-agent/mcp"
      ],
      "command": "npx"
    }
  }
}

[mcp_servers.once]
command = "npx"
args = ["-y", "@once-agent/mcp"]

{
  "mcpServers": {
    "once": {
      "args": [
        "-y",
        "@once-agent/mcp"
      ],
      "command": "npx"
    }
  }
}

{
  "mcpServers": {
    "once": {
      "args": [
        "-y",
        "@once-agent/mcp"
      ],
      "command": "npx"
    }
  }
}

This one needs environment variables set before it will start: ONCE_API_KEY (Optional Once Cloud API key. Required only for tools or integrations that contact Once Cloud, such as once_verify_connection.). The author declared them in the registry entry; get the values from the project itself.