[BUG] OAuth redirect URI "not supported by client" on Mac Mini with Max subscription

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?

Environment

• Claude Code version: 2.1.79
• Node: v25.6.1
• npm: 11.9.0
• OS: macOS (Mac Mini)
• Auth: Claude Max subscription (anwrks@gmail.com)

What's happening

OAuth login fails every time with "Authorization failed - Redirect URI http:/localhost:<port>/callback is not supported by client."

The port changes each attempt (58582, 58725, 58776) but the error is the same.

Note: The redirect URI in the error shows a single slash (http:/localhost)
instead of double (http://localhost) — not sure if that's just the
error page display or the actual URI being sent.

Steps to reproduce

1. claude logout
2. claude
3. Select "Claude account with subscription"
4. Browser opens, logged in as correct account
5. Authorization failed page appears

Attempted fixes

• npm update -g @anthropic-ai/claude-code (updated successfully)
• claude logout + retry (multiple times)
• Different attempts produce different ports, same error

Expected

OAuth flow completes and Claude Code authenticates with Max subscription.

What Should Happen?

it should let me login.

Error Messages/Logs

Steps to Reproduce

Environment

• Claude Code version: 2.1.79
• Node: v25.6.1
• npm: 11.9.0
• OS: macOS (Mac Mini)
• Auth: Claude Max subscription (anwrks@gmail.com)

What's happening

OAuth login fails every time with "Authorization failed - Redirect URI http:/localhost:<port>/callback is not supported by client."

The port changes each attempt (58582, 58725, 58776) but the error is the same.

Note: The redirect URI in the error shows a single slash (http:/localhost)
instead of double (http://localhost) — not sure if that's just the
error page display or the actual URI being sent.

Steps to reproduce

1. claude logout
2. claude
3. Select "Claude account with subscription"
4. Browser opens, logged in as correct account
5. Authorization failed page appears

Attempted fixes

• npm update -g @anthropic-ai/claude-code (updated successfully)
• claude logout + retry (multiple times)
• Different attempts produce different ports, same error

Expected

OAuth flow completes and Claude Code authenticates with Max subscription.

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

Environment - Claude Code version: 2.1.79 - Node: v25.6.1 - npm: 11.9.0 - OS: macOS (Mac Mini) - Auth: Claude Max subscription (anwrks@gmail.com) ## What's happening OAuth login fails every time with "Authorization failed - Redirect URI http:/localhost:<port>/callback is not supported by client." The port changes each attempt (58582, 58725, 58776) but the error is the same. Note: The redirect URI in the error shows a single slash (http:/localhost) instead of double (http://localhost) — not sure if that's just the error page display or the actual URI being sent. ## Steps to reproduce 1. claude logout 2. claude 3. Select "Claude account with subscription" 4. Browser opens, logged in as correct account 5. Authorization failed page appears ## Attempted fixes - npm update -g @anthropic-ai/claude-code (updated successfully) - claude logout + retry (multiple times) - Different attempts produce different ports, same error ## Expected OAuth flow completes and Claude Code authenticates with Max subscription.

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_