"response_format" not available for the Responses API?

API
1

Hello, I am trying to use Structured Outputs with the new Responses API, which according to the docs should be supported. However, including the response_format key in my API request results in the following response:

}
  "error": {
    "message": "Unknown parameter: 'response_format'.",
    "type": "invalid_request_error",
    "param": "response_format",
    "code": "unknown_parameter"
  }
}

This is my API request:

{
  "model": "gpt-4o-mini",
  "input": [
    {
      "role": "user",
      "content": [
        {
          "type": "input_image",
          "image_url": {
            "url": "imageUrl",
            "detail": "auto"
          }
        }
      ]
    }
  ],
  "response_format": {
    "type": "json_schema",
    "json_schema": {
      "name": "receipt_parser",
      "strict": true,
      "schema": {
        "type": "object",
        "properties": {
          "purchase_date": {
            "type": "string",
            "description": "The date of purchase in ISO 8601 format (Year-Month-Day)"
          },
          "tax_paid": {
            "type": "number",
            "description": "The order tax paid"
          }
        },
        "required": [
          "purchase_date",
          "tax_paid"
        ],
        "additionalProperties": false
      }
    }
  },
  "user": "965",
  "meta": {
    "tenant_id": "1"
  }
}

Are my parameters wrong or are the API docs maybe inaccurate? Any insight is appreciated thank you.

2

The parameters attempted are wrong.

If you want an enforced output format that is not just text, then (logically??) you have to send the text parameter.

{
  "model": "gpt-4o",
  "input": [...],
  "text": {
    "format": {
      "type": "json_schema",
      "name": "response_schema",
      "strict": true,
      "schema": {
        "type": "object",
        "properties": {
          "answer_to_user": {
            "type": "string",
            "description": "The answer provided to the user."
          },
          "discussion_topic": {
            "type": "string",
            "description": "The main topic of discussion."
          }
        },
        "required": [
          "answer_to_user",
          "discussion_topic"
        ],
        "additionalProperties": false
      }
    }
  },
  "max_output_tokens": 2048,
  "top_p": 0.9,
  "store": false
}
3

Ohhh got it, I just assumed the parameter name would be the same. That makes sense thank you so much!