[BUG] Switching model switches it across all open sessions, instead of only in the current session

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

I switch from Opus to Sonnet in a certain session where I need less token consumption, but it switches it on every session that I have currently open.

What Should Happen?

The model should be switched only in the session where I am switching, the other one should continue using the one that they used.

Error Messages/Logs

Steps to Reproduce

Open two cloud sessions in two terminal windows, switch model in one, observe that the model is switched in the second one as well.

Claude Model

Not sure / Multiple models

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.0.54

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

iTerm2

Additional Information

_No response_