[BUG] vs code claude extension 2.1.74 need disable adaptive thinking when the custom end point not support the adaptive parameter

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?

scenario

upgrade the vs code claude extension to 2.1.74 and use a base_url which does not support the adaptive parameter will encounter following errors

API Error: 400 {"error":{"message":"{"type":"error","error":{"type":"invalid_request_error","message":"thinking: Input tag 'adaptive' found using 'type' does not match any of the expected tags: 'disabled', 'enabled'"},"request_id":"req_vrtx_011CYxgzty4JMfWjn9HrqoX3"}. Received Model Group=claude-4.5-sonnet\nAvailable Model Group Fallbacks=None","type":"None","param":"None","code":"400"}}

mitigation

need to set the environment variable in claude setting.json to avoid the claude extension to send the adaptive
parameter

"CLAUDE_CODE_DISABLE_ADAPTIVE_THINKING": 1

I think this is not an issue for the anthropics claude but more related to the user(me) should not use a endpoint
which does not support the new spec but just record here if it help someone

If I misunderstood the concepts here , I will be glad to learn from your comments.

What Should Happen?

I think the new version of the claude cli and claude vs code extension should be compatible with the endpoint which does not support the adaptive parameter.

Error Messages/Logs

API Error: 400 {"error":{"message":"{"type":"error","error":{"type":"invalid_request_error","message":"thinking: Input tag 'adaptive' found using 'type' does not match any of the expected tags: 'disabled', 'enabled'"},"request_id":"req_vrtx_011CYxgzty4JMfWjn9HrqoX3"}. Received Model Group=claude-4.5-sonnet\nAvailable Model Group Fallbacks=None","type":"None","param":"None","code":"400"}}

Steps to Reproduce

update to the latest version of the claude vs code extension
and use a custom endpoint which does not support the adaptive parameter

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

2.0.29

Claude Code Version

2.1.74

Platform

Other

Operating System

macOS

Terminal/Shell

VS Code integrated terminal

Additional Information

_No response_