[salamo]

Possible reasons:

- They might be dynamically adjusting these at inference time [1]. For example, start with a low temperature and generate samples with increasingly high temperatures until one of them passes some quality gate.

- They don't want you to fine-tune on high temperature completions (rejection fine-tuning). You could call this "rejection fine-tuning rejection".

[1] https://rlhfbook.com/c/09-rejection-sampling#related-best-of...

[regularfry]

Couple of other more businessy reasons:

- SynthID hides the watermark in the sampling RNG. No randomness -> no watermark.

- If you want to distil on the model outputs, you want temp=0 outputs. No temp=0 -> worse distillation.

[orbital-decay]

You probably don't want temp 0, especially with Gemini which often fails in the greedy sampling mode in practice, often in ridiculous ways (e.g. multiple thousand token loops). As another comment says it's pretty brittle and this is even reflected in their docs somewhere IIRC. You want the "normal" temperature (whatever it is) and oversampling if necessary.

Certain open models have/had the temperature locked on the official APIs, I assume they just have sampling incompatible with static temperature or do some fancy speculative decoding. It's clearly not to hide anything, as the weights are open and there are always alternative providers.