[BUG] Signing in to VS code returns a 400 error

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 trying to sign into claude code through vs code, i have to sign in through the console, every other way i try to sign in, there is a 400 error. This is very annoying because claude randomly signs me out and your verification emails take 10 minutes just to hit the inbox

What Should Happen?

i should not get a 400 error

Error Messages/Logs

Steps to Reproduce

logging into vs code, dont use the console, try signing in with the email.

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

claude-sonnet-5

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

VS Code integrated terminal

Additional Information

_No response_