[BUG] Sonnet 4.6 reply box freezes during chats

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?

[BUG] Sonnet 4.6 reply box freezes after a detailed research assignment on desktop chat app. This was reported last month. This does not happen with Opus 4.7.

What Should Happen?

Reply box should not freeze

Error Messages/Logs

Steps to Reproduce

1. Assign Sonnet 4.6 a deep research assignment on a stock using the desktop chat app.
2. Discuss its findings with at least three replies. Have it compare the stock to a similar stock

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

Version 1.6608.2

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Other

Additional Information

_No response_