> The user agent is the proper channel for the agency Jake is seeking here. Theres nothing preventing the user & their user agent from negotiating what model they use.

This isn't how it works. As the developer, you use the system prompt to set a particular personality for the chat bot. Eg, when you use an LLM in VSCode, it comes with a system prompt to make it an effective code assistant.

Now, in VSCode, you can select a different model, which is maybe where your misconception comes from. But when you select a different model, it will also use a different system prompt, designed to achieve the same personality, but tailored for that particular model.

Once you figure out why they do that, you'll understand why your position here doesn't make sense.

I guess some people don't have access to their system prompt, but that's never been the case for me?

I believe at $LASTJOB even Azure's web GUI let you meddle with that. This isn't cast quite so deeply in stone.

That said I do think it's ok that the app developer ask for British English. My overall concern is more that concern about model behavior & expectations feel very tight & narrow across this, and I don't think the typical well defined rigor and expectations if applied will ever ever ever let LLMs on the web. I think sites see that, I think users see that. Making perfect the enemy of the good is going to doom any attempt, forever, and no progress is possible, if these are the demands. We have to be willing to accept that models are limited, especially small local ones. That's ok.