[BUG] OAuth login fails: Unknown scope user:mcp_servers

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?

Claude Code 2.1.75+ requests scope user:mcp_servers which the auth server rejects as unknown. Versions before 2.1.75 lack code_challenge which is now required.

No working version exists for Pro user OAuth login.

Steps to reproduce:

1. Run claude on a headless server
2. Copy the OAuth URL to a browser
3. Auth server returns: Invalid OAuth Request - Unknown scope: user:mcp_servers

Version: 2.1.87 (also tested 2.1.75-2.1.86)

What Should Happen?

unable to authenticate:

Claude Code 2.1.75+ requests scope user:mcp_servers which the auth server rejects as unknown.
Versions before 2.1.75 lack code_challenge which is now required.

Error Messages/Logs

Steps to Reproduce

Steps to reproduce:

1. Run claude on a headless server
2. Copy the OAuth URL to a browser
3. Auth server returns: Invalid OAuth Request - Unknown scope: user:mcp_servers

• 2.1.75 - 2.1.87: "Unknown scope: user:mcp_servers"
• 2.1.55 - 2.1.74: "Missing code_challenge parameter"
• 2.1.0: "Redirect URI not supported"

Claude Model

None

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

2.1.86

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

Other

Additional Information

_No response_