[BUG] Fable 5.1 burns tokens faster than 5.0 100% of limit in 20 mins.

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?

Fable 5.1 medium burns through 100% of claude code limit in under 20 mins!!! its even less token efficient than 5.0 even though you report it as more efficient.

What Should Happen?

Fable 5.1 medium burns through 100% of claude code limit in under 20 mins!!! its even less token efficient than 5.0 even though you report it as more efficient.

Error Messages/Logs

Steps to Reproduce

Fable 5.1 medium burns through 100% of claude code limit in under 20 mins!!! its even less token efficient than 5.0 even though you report it as more efficient.

Claude Model

Other

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.257

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

VS Code integrated terminal

Additional Information

_No response_