From the migration guide: >> Sampling parameters removed: Setting temperature, top_p, or top_k to any non-default value on Claude Opus 4.7 returns a 400 error.
Let's set aside that this should probably be a deprecation warning and not a 400. Not having these dials limits utility for cases like synthetic data generation, natural language QA and many more. Even though temp=0 does not guarantee determinism, getting 99 identical responses out of 100 is reasonably close to determinism for most practical use case. Default temp gives you wild swings in performance which temp=0 almost perfectly eliminates. And there are valid use cases for using temp=0 or experimenting with different values.
The writing was on the wall since even earlier Opus versions would override temperature setting and reset to default when thinking was enabled. Now there is no way to control it at all. It is a bit disappointing.
I understand most people around here will be using Opus in Claude Code or in another harness for coding, and in that case you are not really affected. But for those of you building products and using the API in different ways, how are you dealing with this change?
If anyone from Anthropic is reading this, any insights into why it was removed would be great. I am struggling to believe this is because of distillation concerns. Thanks!