const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    model: 'openai/gpt-5-nano',
    stream: false,
    input: [{role: 'user', content: 'Give me the current datetime in Asia/Tokyo.'}],
    tools: [{type: 'gateway:datetime', parameters: {timezone: 'Asia/Tokyo'}}],
    tool_choice: 'auto'
  })
};

fetch('https://api.phaseo.app/v1/responses', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

{
  "id": "<string>",
  "object": "<string>",
  "created": 123,
  "model": "<string>",
  "output": [
    {
      "type": "<string>",
      "role": "<string>",
      "content": [
        {
          "type": "output_text",
          "text": "<string>",
          "annotations": [
            {}
          ]
        }
      ],
      "call_id": "<string>",
      "name": "<string>",
      "arguments": "<string>"
    }
  ],
  "output_items": [
    {
      "type": "<string>",
      "role": "<string>",
      "content": [
        {
          "type": "output_text",
          "text": "<string>",
          "annotations": [
            {}
          ]
        }
      ],
      "call_id": "<string>",
      "name": "<string>",
      "arguments": "<string>"
    }
  ],
  "content": [
    {}
  ],
  "role": "<string>",
  "stop_reason": "<string>",
  "type": "<string>",
  "usage": {
    "prompt_tokens": 123,
    "completion_tokens": 123,
    "total_tokens": 123,
    "server_tool_use": {
      "datetime_requests": 1
    }
  }
}