Supporting MCP Servers in `runTools` function

[rabisg]

Confirm this is a feature request for the Node library and not the underlying OpenAI API.

• This is a feature request for the Node library

Describe the feature or improvement you're requesting

runTools has been a great addition to the node library, greatly improving DX. This proposal is about extending the runTools functionality to support MCP servers directly instead of having to call mcp.listTools and mcp.callTool separately within your own code. Something like:

tools: [
  {
    "type": "function",
    "function": {
      "name": "internal_tool",
      {...}
    }
  },
  {
    "type": "mcp_server",
    "server": {
      "host": "127.0.0.1",
      "port": 8000,
      {...}
    }
  },
  {
    "type": "mcp_server",
    "server": {
      "host": "mcp.external-service.com",
      {...}
    }
  }
]

Would that be something the OpenAI team would consider adding. The code for it would be simple enough - I can even send a PR if we agree on the direction and the interface for it.

Additional context

No response