MCP Store: Supabase template OAuth fails with "Unrecognized client_id"

[KarloAldrete]

Bug Description

Installing the Supabase MCP server template from the MCP Store fails during OAuth authorization. The browser redirects to Supabase with a client_id that Supabase rejects as unrecognized.

How to reproduce

1. Open PostHog Code
2. Go to MCP Servers / MCP Store
3. Click install on the Supabase template
4. Browser opens:

   https://api.supabase.com/v1/oauth/authorize?client_id=18038368-50b4-4095-a1b6-b67b73417452&redirect_uri=https%3A%2F%2Fus.posthog.com%2Fapi%2Fmcp_store%2Foauth_redirect%2F&response_type=code&...
   

5. Supabase returns: {"message": "Unrecognized client_id"}

Expected behavior

OAuth flow should complete successfully and the Supabase MCP server should be installed and connected.

Actual behavior

The client_id embedded in the authorization URL is rejected by Supabase. This means the OAuth app credentials stored in the Supabase template (MCPServerTemplate.oauth_credentials on the PostHog backend) are either stale, incorrect, or the app was never properly registered on Supabase's side.

Environment

• PostHog Code: v0.52.9 (commit 890696c)
• Platform: Linux x86_64
• PostHog region: US (us.posthog.com)

Pointers

The OAuth flow for template-based installs is handled in:

• apps/code/src/renderer/features/mcp-servers/hooks/useMcpServers.ts — installTemplateWithOAuth()
• apps/code/src/renderer/api/posthogClient.ts — installTemplateWithOAuth() API call
• Backend template model: products/mcp_store/backend/models.py in PostHog/posthog — MCPServerTemplate.oauth_credentials

The fix likely requires updating the client_id/client_secret in the Supabase template record via Django admin on the PostHog backend, or re-registering the OAuth app on Supabase.