Adapter specific system prompts?

[iamthebot]

Maybe I'm missing this from browsing the docs... but is it possible to set a default system prompt on an adapter (or even model/deployment) level? It seems it can either only be done globally or by selecting the system prompt from a list of custom prompts after you've started the adapter.

Eg; I find myself needing different system prompts for Gemini 2.5 vs. GPT-4.5 or even the new GPT-5.

[olimorris]

I'm pretty sure if you search "system prompt" its the first thing that comes up in the docs