- reasoning_effort "minimal" was not renamed to "none"; "none" is a new, faster level supported by GPT-5.1 but not GPT-5 - there's no good reason it's called "

- reasoning_effort "minimal" was not renamed to "none"; "none" is a new, faster level supported by GPT-5.1 but not GPT-5 - there's no good reason it's called "chat" instead of "Instant" - gpt-5.1 and gpt-5.1-chat are different models, even though they both reason now. gpt-5.1 is more factual and can think for much longer. most people want gpt-5.1, unless the use case is ChatGPT-like or they prefer its personality.