curl --request POST "https://gptproto.com/v1/chat/completions" \
  --header "Authorization: Bearer $GPTPROTO_API_KEY" \
  --header "Content-Type: application/json" \
  --data '{
    "model": "grok-4",
    "messages": [
      {
        "role": "user",
        "content": [
          {
            "type": "text",
            "text": "這張圖片中有什麼？"
          },
          {
            "type": "image_url",
            "image_url": {
              "url": "https://tos.gptproto.com/resource/cat.png"
            }
          }
        ]
      }
    ],
    "max_tokens": 300
  }'