Figma MCP OAuth token not persisting after successful authentication

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?

After completing Figma MCP OAuth authentication (getting "Authentication Successful" message), the token is not being saved to
~/.claude/settings.json. The old/expired token remains in the file, and mcp-needs-auth-cache.json is immediately recreated marking
Figma as needing authentication again.

What Should Happen?

New OAuth token should be written to settings.json

Error Messages/Logs

Token remains unchanged, authentication loop continues

Steps to Reproduce

Steps to Reproduce:

1. Configure Figma MCP in settings.json
2. Run /mcp and authenticate through OAuth flow
3. Complete authentication successfully (see success message)
4. Check settings.json - token is unchanged
5. Run /mcp again - still shows as needing authentication

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

Claude Code 2.1.121 (macOS

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_