[BUG] Figma MCP OAuth token not recognized on restart — re-authentication required every session

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, the token is saved in ~/.claude/.credentials.json (mcpOAuth.figma entry with valid accessToken exists), but mcp-needs-auth-cache.json is overwritten on every restart, flagging Figma as "Needs authentication". Re-authentication is required on every new Claude Code session.

Related to #54727 but different symptom: occurs on every restart even with a single Claude Code process.

What Should Happen?

After OAuth authentication, the Figma MCP server should remain authenticated across sessions. The token stored in .credentials.json should be recognized on restart without requiring re-authentication.

Error Messages/Logs

claude mcp list shows:
figma: https://mcp.figma.com/mcp (HTTP) - ! Needs authentication
(shown after every restart, even when .credentials.json contains a valid mcpOAuth.figma token)

Steps to Reproduce

1. Add Figma MCP server via Claude Code marketplace
2. Authenticate with OAuth (complete the browser flow successfully)
3. Confirm ~/.claude/.credentials.json contains mcpOAuth.figma with valid accessToken and refreshToken
4. Restart Claude Code
5. Run claude mcp list → Figma shows "Needs authentication" again

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.123

Platform

Other

Operating System

Windows

Terminal/Shell

VS Code integrated terminal

Additional Information

_No response_