[BUG] Claude Code for VS Code selects the wrong model, mismatches whats displayed in UI.

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?

Using the latest claude code + vscode extension, The prompt doesn't set the correct model when opened. It shows Sonnet 4.6 1M, but context window runs out quickly and when asked, claude reports its at 200k context window and running Sonnet 4.5.

You can get it to select the correct model by:

1. Opening a new prompt
2. Switching from the preselected one to a different one
3. Switching back to the one you want

But this is very janky and the UI mismatch is quite intrusive in workflows.

In CLI the model command does work as expected.

What Should Happen?

The model shown in the UI should always match whats actually selected for the session.

Error Messages/Logs

Steps to Reproduce

Open a claude prompt. Literally.

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

2.1.91 (Claude Code)

Platform

Google Vertex AI

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

_No response_