[BUG] Log in via OAuth is far too frail

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 authenticate my login, either on my personal account or company SSO, I and other colleagues are met with this frustrating exercise where the "Authorize" page appears for a brief instant before automatically redirecting to the onboarding page.

When I've been able to get past this on my personal account I am met with the next obstacle, either something like so:

Failed to authenticate. API Error: 401 {"type":"error","error":{"type":"authentication_error","message":"OAuth token has expired. Please obtain a new token or refresh your existing token."},"request_id":"req_011CZFhX468npdpSc4zPYSX6"}

The OAuth token can't expire after just thirty seconds.

or it just makes me login in via email again.

What Should Happen?

This workflow is incredibly annoying, and it happened to me in January on my personal account and again to several of my colleagues just yesterday. There are other bugs about this and you haven't really fixed it; if you give me a link to paste in my browser it should just take me to the authorization page without immediately punting me to onboarding.
This seems like a very basic thing and the fact you haven't addressed it reflects poorly on your product.

Error Messages/Logs

Steps to Reproduce

Just try to log in with your account on Claude CLI or any extension as if you were doing it for the first time.

Claude Model

None

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

Any

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_