[BUG] 2.1.68 Sends effort parameter when using custom model

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?

We are using AWS Bedrock and using an inference profile , after the 2.1.68 update its trying to send the effort parameter but, our claude sonnet 4.5 on bedrock govcloud doesn't support it. We get ⎿ API Error: 400 This model does not support the effort parameter.

Need a way to disable effort parameter on custom model.

What Should Happen?

Have a setting we can specify to disable effort parameter when using custom model.

Error Messages/Logs

API Error: 400 This model does not support the effort parameter.

Steps to Reproduce

Reproduction is hard unless you have access to a model that doesn't support effort and you set it up as a custom model.

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

2.1.66

Claude Code Version

2.1.68

Platform

AWS Bedrock

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_