[BUG] OAuth login fails - "Missing code_challenge" / Invalid OAuth Request on Max subscription

[prezis]

Preflight Checklist

• I have searched existing issues and this hasn't been reported yet
• This is a single bug report (please file separate reports for different bugs)
• I am using the latest version of Claude Code

What's Wrong?

OAuth login fails with "Invalid OAuth Request - Missing code_challenge parameter"
when using /login with Max subscription on Ubuntu Linux.

The URL generated by Claude Code contains invalid parameters that cause
claude.com to reject the request.

Workaround: manually edit the OAuth URL before opening in browser:

1. Remove "code=true&" from the beginning of query params
2. Remove "org%3Acreate_api_key+" from the scope parameter

This works correctly after editing.

What Should Happen?

Browser opens the OAuth authorization page, user logs in,
receives a code to paste back into the terminal, and Claude Code
authenticates successfully with the Max subscription.

Error Messages/Logs

Invalid OAuth Request - Missing code_challenge parameter

Steps to Reproduce

1. Run /login in Claude Code
2. Press "c" to copy the OAuth URL
3. Paste URL in browser without modification
4. Browser shows "Invalid OAuth Request - Missing code_challenge parameter"

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

No response

Claude Code Version

Claude Code 2.1.96.

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

[github-actions]

Found 3 possible duplicate issues:

1. [BUG] Linux OAuth flow fails for subscription users due to unsupported org:create_api_key scope #44531
2. [BUG] OAuth login fails on Linux/VPS: code_challenge_method missing in authorization request #43996
3. [BUG] Invalid OAuth Request - Unknown scope: user:sessions% #26874

This issue will be automatically closed as a duplicate in 3 days.

• If your issue is a duplicate, please close it and 👍 the existing issue instead
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🤖 Generated with Claude Code

[github-actions]

This issue has been automatically closed as a duplicate of #44531.

If this is incorrect, please re-open this issue or create a new one.

🤖 Generated with Claude Code

[github-actions]

This issue has been automatically locked since it was closed and has not had any activity for 7 days. If you're experiencing a similar issue, please file a new issue and reference this one if it's relevant.