[BUG] turning off thinking (TAB) does not turn off thinking when MAX_THINKING_TOKENS is set

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?

turning off thinking (TAB) does not turn off thinking when MAX_THINKING_TOKENS is set

What Should Happen?

turning off thinking should turn off thinking despite MAX_THINKING_TOKENS being set

Error Messages/Logs

Steps to Reproduce

set MAX_THINKING_TOKENS
turn off thinking
tell claude not to think
see claude getting frustrated because they are still thinking despite being told not to 🥺

Claude Model

Opus

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

2.0.54

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

Other

Additional Information

_No response_