We won’t be adding GPT-5 to the Assistants API beta. The Responses API was built for reasoning models like GPT-5, and the Assistants API simply doesn’t do GPT-5 justice. It misses the multi-turn interactions, reasoning summaries, tools, and statefulness of Responses. As we mentioned in the announcement of the Responses API, we plan to wind-down the Assistants beta—and we’ll share more news about that soon.