The objects you receive back from these APIs will differ slightly. In Chat Completions, you receive an array of
`choices`, each containing a `message`. In Responses, you receive an array of Items labeled `output`.

```json
{
    "id": "resp_68af4030592c81938ec0a5fbab4a3e9f05438e46b5f69a3b",
    "object": "response",
    "created_at": 1756315696,
    "model": "gpt-5.5",
    "output": [
      {
        "id": "rs_68af4030baa48193b0b43b4c2a176a1a05438e46b5f69a3b",
        "type": "reasoning",
        "content": [],
        "summary": []
      },
      {
        "id": "msg_68af40337e58819392e935fb404414d005438e46b5f69a3b",
        "type": "message",
        "status": "completed",
        "content": [
          {
            "type": "output_text",
            "annotations": [],
            "logprobs": [],
