[BUG] Overthinking

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?

Shocking amount of token consumption during standard thinking in 2.0.76. Performance dramatically slower -- simple actions taking 1-2 minutes. Consumption way higher. Getting 15k tokens of thinking without tool use on one to two sentence request, and no suggestion of ultrathink --> altering 10 lines of code.

What Should Happen?

Normal behavior.

Error Messages/Logs

Steps to Reproduce

Make any old request.

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

2.0.75

Claude Code Version

2.0.76

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_