Hey, thanks for the report. This is a known issue with the OAuth flow for MCP servers. I can see the screenshot with the error “OAuth authorization request does not exist”. The bug is that the OAuth redirect isn’t firing correctly.
Two workarounds:
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In Cursor Settings > MCP, click the “Needs authentication” text under the server name (not the Connect button). This sometimes triggers the auth flow correctly.
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If that doesn’t work, open the Output panel (View > Output), select “MCP: Supabase” in the dropdown, click Connect, and copy the auth URL from the logs (it starts with
https://api.supabase.com/v1/oauth/authorize?...). Open that URL manually in your browser and complete the authorization.
Related thread with more details: MCP Servers with auth do not open browser anymore
The team is aware of the bug. No timeline yet, but it’s being worked on. Let me know if the workarounds help.