[BUG] claude.ai/design infinite login redirect loop — authenticated Max plan user

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?

Bug Description

When navigating to claude.ai/design, the browser enters an infinite
redirect loop between /design and /login, making the page completely
inaccessible.

Steps to Reproduce

1. Go to https://claude.ai/design
2. Page immediately redirects to:

https://claude.ai/login?returnTo=%2Fdesign

1. After login attempt, redirects back to /design
2. Loop repeats infinitely — page never loads

Expected Behavior

Successfully authenticate and access Claude Design workspace.

Actual Behavior

Infinite redirect loop: /design → /login?returnTo=%2Fdesign → /design → ...

What I've Tried

• Multiple browsers (normal + incognito) → same issue
• Changed DNS → no effect
• Other claude.ai pages (chat, projects) work perfectly fine
• Issue is isolated to claude.ai/design only

Environment

• Plan: Claude Max
• Location: Vietnam
• Browser: [Chrome / Firefox — điền vào]
• OS: [Windows / Mac — điền vào]

Notes

This appears to be a server-side authentication issue specific to the
/design route, not a client-side or network problem.

What Should Happen?

After logging in, the user should be redirected to claude.ai/design
and able to access the Claude Design workspace without any loops or errors.

Error Messages/Logs

Steps to Reproduce

1. Open any browser (tested on normal and incognito mode)
2. Navigate to https://claude.ai/design
3. Page immediately redirects to https://claude.ai/login?returnTo=%2Fdesign
4. Enter login credentials and submit
5. Page redirects back to https://claude.ai/design
6. Step 3 repeats — infinite redirect loop, page never loads

Claude Model

None

Is this a regression?

I don't know

Last Working Version

it's web interface

Claude Code Version

it's web interface

Platform

Other

Operating System

macOS

Terminal/Shell

Other

Additional Information

_No response_