[BUG] In VSCode extension, is model switching via /model isolated per chat session? Seems like it might not be.

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?

This impacts multi-agent workflows where different models are used for different roles (e.g., Opus for audit, Sonnet for implementation).

This issue is really a question or questions about current behavior. Its bug status depends on the answer(s).

• Using VSCode Claude Code extension
• Two chat windows open simultaneously
• Window A set to Opus
• Window B changed to Sonnet via /model
• /model in Window A still reports Opus
• But behavior suggests it may actually be using Sonnet (possible mismatch), and it reports itself as Sonnet instead of Opus

Concern:

• Model selection might be shared/global rather than per-session
• Does selecting a new model in chat B also change it silently for chat A?
• what is shown by /model in a chat window may be stale or misleading if it is changed in another chat window
• if the /model changes silently in chat A, it definitely is not reflected when looking at the GUI to see what model and Effort are selected

What Should Happen?

Expected:

• Model selection should be clearly scoped (per chat vs global)
• Selecting a model in one chat should never affect the model being used in another
• /model should reflect actual execution model, not cached state

Impact:

• Difficult to trust model behavior during multi-window workflows

I understand that this may not be a bug. So please interpret it as a clarifying question that was motivated by thinking it might be acting like this, which would certainly be something to fix.

Thank you for your time and patience, and the great tool

Error Messages/Logs

Steps to Reproduce

• Open VSCode
• Open VSCode Claude Code extension chat
• Window A: Select Opus with Extra High Effort (or any model with any effort)
• Window A: Do some work with it
• Window B: Open a new chat to work in parallel
• Window B: Select a different model and effort; for example, Sonnet with High Effort.
• Window B: Do some work with it
• Go back to Window A to prompt some more work
• Did the model in Window A change? (for example to Sonnet with High Effort)?
• If so, the model and effort reported are incorrect.

Performance changes in Window A after the model change in Window B made me concerned about this. I apologize if the concern is not justified.

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.112 (Claude Code)

Platform

Other

Operating System

macOS

Terminal/Shell

VS Code integrated terminal

Additional Information

I am not using Terminal actually. Just the VSCode extension.