Getting error code 400 on both Vision and PDF base64 input - Response API

A 400 will also have an error message associated with it. For example, a wrong message construction:

— ERROR: gpt-5.5: Error code: 400 - {‘error’: {‘message’: “Invalid type for ‘input[0].content[0]’: expected an object, but got a string instead.”, ‘type’: ‘invalid_request_error’, ‘param’: ‘input[0].content[0]’, ‘code’: ‘invalid_type’}}

What’s yours?

You can try store:false and see if they will go. Maybe OpenAI doesn’t want to be in the business of keeping your 4MB x every request you make, forever?