Hello!
I switched my model to GPT-5 and GPT-5-mini with my Response API python implementation.
After the switch, I keep experiencing the following error:
openai.BadRequestError: Error code: 400 - {'error': {'message': \"Item 'rs_689ad59654dc8192852a1972d0dcb89d08577a79a12eedb6' of type 'reasoning' was provided without its required following item.\", 'type': 'invalid_request_error', 'param': 'input', 'code': None}}"
This occurs after the initial turn.
For the initial turn, I send a set of developer and system instruction together with static user prompt.
The initial turn will analyze some data set uploaded via Container API.
Then after we receive the response, we store the responseId and use it as previous_response_id.
This enables our service to allow further interaction with the AI with context.
Before switching, we were using GPT-4.1 and GPT-4.1-mini which was fine and no problems.