[BUG] Sonnect 4.6 1M context is not available in claude desktop app but available in terminal mode with same enterprise account

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?

Sonnect 4.6 (1M context) is not visible in model selection picker.

<img width="348" height="333" alt="Image" src="https://github.com/user-attachments/assets/b2a3f725-2998-490f-b260-1d7be251fc7b" />

What Should Happen?

Sonnect 4.6 (1M context) should be available to choose.

Error Messages/Logs

Steps to Reproduce

1. Open model picker

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.150

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_