[BUG] extended thinking doen't work (think, think hard, think harder)

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've used Claude Code in wsl2. An hour ago, think, think hard worked very well. But after update to 4.5 sonnet, It doesn't work. I've typed think , think hard, think harder many times but CC doesn't think at all. How do I activate thinking mode?

What Should Happen?

It should work extended thinking.

Error Messages/Logs

Steps to Reproduce

input think but it doesn't think.

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

Claude Code version 0.5.1

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

WSL (Windows Subsystem for Linux)

Additional Information

_No response_