[BUG] claude with model sonnet[1m] doesn't work on a max 20x account

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?

When I try to send a message to claude code with model sonnet[1m] , I get an api error 400 with the error message, that this is not available even though it should be for a max subscription.

What Should Happen?

1m token model should work.
claude should accept and process the message

Error Messages/Logs

API Error: 400 {"type":"error","error":{"type":"invalid_request_error","message":"The long context beta is not yet available for this
     subscription."},"request_id":"req_011CURLE93ofJ1vxsx66Ykfo"}

Steps to Reproduce

change to this model run any command "/model=sonnet[1m]"

Claude Model

Sonnet (default)

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

2.0.24

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

_No response_