[BUG]

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?

Title: Supabase MCP server fails to reconnect after re-login - "resource: Resource must be a valid MCP endpoint"

Description:

After being forced to log back into Claude Code, my Supabase MCP server connection broke and will not reconnect. /mcp shows the error:

{"message":"resource: Resource must be a valid MCP endpoint"}

Earlier attempts also showed: "Subprocess initialization did not complete within 60000ms - check authentication and network connectivity"

Steps already taken, none fixed it:

1. Full reboot of the machine
2. Removed the supabase entry from .mcp.json, restarted Claude Code, confirmed it disappeared from /mcp, then re-added the exact same entry and restarted again - same error
3. Deleted the local mcp-needs-auth-cache.json marker file
4. Verified network connectivity to the endpoint directly: curl to https://mcp.supabase.com/mcp?project_ref=eexmaauhulkmkuxmueny returns a fast HTTP 401 (expected without auth) in under 0.3s - confirms DNS/TLS/routing all work fine and the endpoint is up
5. Fully logged out of Claude Code and logged back in - same error persists

The .mcp.json config is:
{
"mcpServers": {
"supabase": {
"type": "http",
"url": "https://mcp.supabase.com/mcp?project_ref=eexmaauhulkmkuxmueny"
}
}
}

This same config worked fine before I was forced to re-login to Claude. The error is identical before and after every reset attempt, which suggests the problem is server-side (in how Claude Code's account/session now brokers the OAuth handshake to this remote MCP server) rather than anything fixable from my local machine.

Platform: Windows 11
Claude Code: VSCode extension / CLI

What Should Happen?

should authorise supabase

Error Messages/Logs

{"message":"resource: Resource must be a valid MCP endpoint"}

Steps to Reproduce

/mcp
authorize

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.150

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

VS Code integrated terminal

Additional Information

_No response_