[BUG] [BUG] Supabase MCP OAuth token not persisting between sessions on Windows - Claude Code Desktop

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?

Description:
Supabase MCP works correctly in existing conversations but fails to connect in new conversations in Claude Code Desktop on Windows 11. The OAuth token does not persist between sessions, requiring manual re-authentication every time a new conversation is started.
Environment:

OS: Windows 11
App: Claude Code Desktop
MCP Server: Supabase (https://mcp.supabase.com/mcp)
Transport: HTTP/OAuth

Behavior:

Old conversations: Supabase MCP connects and works correctly
New conversations: Supabase MCP shows as disconnected/unauthenticated
There is no clear way to re-authenticate within Claude Code Desktop UI — /mcp does not work in the Desktop app the same way it does in the CLI

Expected: OAuth token persists across new conversations without requiring re-authentication
Actual: Must re-authenticate on every new conversation with no working UI path to do so in Claude Code Desktop on Windows
Additional context: This appears related to issues #29132, #40582, and #43 but specifically affects the Desktop app UI on Windows where the re-auth path available in the CLI (/mcp) does not function.

What Should Happen?

Expected: OAuth token persists across new conversations without requiring re-authentication

Error Messages/Logs

mcp not connecetd error is persistent even after re running the connectors deleting and reinstalling claude desktop and the connectors

Steps to Reproduce

1. Open Claude Desktop
2. Press + for New Conversation
3. Watch the errors flow

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

this worked two days ago

Claude Code Version

2.1.105 (claude Code)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

Everything worked fine two days ago. This morning, nothing worked. I haven't changed anything since then.