Sandbox artifact LLM calls locked to sonnet 4.0

Hi there.

I'm using Claude's artifact sandbox to create a writing assistant integrated with the LLM. The code calls the AI multiple times to generate text using a specific database source embedded in the code.

The problem I'm having is that I can't use Sonnet 4.5 or Opus, since all LLM calls return responses indicating that Sonnet 4.0 was used — even when I explicitly set the model in the code. Is it possible to use the 4.5 version inside the artifact, given that it consumes my Max subscription anyway?