[BUG] Not able to run claude code without thinking mode

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?

Error

 API Error: 400 {"type":"error","error":{"type":"invalid_request_error","message":"`clear_thinking_20251015` strategy requires `thinking` to be 
     enabled"},"request_id":"req_011CVCvpKEJmX4g6Hv2rQtGU"}

When Im trying to use CC without thinking mode enabled, Im getting the above error. No solutions around to resolve this. It was all working fine suddenly it started happening

Claude version- Claude Code v2.0.36

What Should Happen?

Should be able to use CC without thinking too.

Error Messages/Logs

Steps to Reproduce

1. Thinking mode is set to off
2. Type any prompt
3. It throws the error

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.0.36

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_