{
  "id": "msg_thinking_x",
  "type": "message",
  "role": "assistant",
  "model": "claude-sonnet-4-5",
  "content": [
    {
      "type": "thinking",
      "thinking": "Let me think. 2 + 2 = 4.",
      "signature": "abc123sig=="
    },
    {
      "type": "text",
      "text": "The answer is 4."
    }
  ],
  "stop_reason": "end_turn",
  "stop_sequence": null,
  "usage": {
    "input_tokens": 15,
    "output_tokens": 20
  }
}