Why do gpt-5.1 and gpt-5.4-mini behave so differently in production chatbot use cases?

@vb You touched on a very interesting point. Actually, I haven’t tested changing reasoning.effort on either model yet. I thought about it, but I didn’t try it in practice.

From what I found in the OpenAI docs, gpt-5.1 supports none, low, medium, and high, and its default is none. For gpt-5.4-mini, the model page shows support for none, low, medium, high, and xhigh, but I didn’t find an explicit default stated there.

Do you recommend testing gpt-5.4-mini with a higher reasoning.effort, such as high or xhigh?

My main concern is: if I increase reasoning.effort on gpt-5.4-mini, could it end up with similar latency/cost conditions as gpt-5.1, reducing the advantage of using the mini model?