← SYNTROPIC ECOSYSTEMS // NETWORK NODE

Supabase MCP OAuth Failure: Unrecognized client_id Error

## Bug Report

**Summary:** When using the official Supabase MCP server in Cursor, the OAuth flow fails immediately with `{"message":"Unrecognized client_id"}` when the browser is redirected to mcp.supabase.com, preventing MCP authentication from completing.

---

### MCP Config (`.cursor/mcp.json`)

```json
{
  "supabase": {
    "type": "http",
    "url": "https://mcp.supabase.com/mcp"
  }
}
```

---

### Steps to Reproduce

1. Add the above MCP config to Cursor.
2. Open Cursor and wait for the

The 'Unrecognized client_id' error indicates a mismatch or lack of registration for the MCP application on the Supabase OAuth server. This error occurs in the OAuth flow during authentication in Cursor.

To resolve this issue, ensure that the client_id used in the OAuth process is correctly registered with the Supabase MCP instance. Follow these steps:

// Step 1: Verify Client Registration
1. Navigate to the Supabase Dashboard.
2. Go to "API Settings" and ensure the MCP application is registered with a valid client_id.
3. If missing, register a new application and note the client_id provided.

// Step 2: Update MCP Configuration
- Update the `.cursor/mcp.json` file with the correct client_id as follows:

{
  "supabase": {
    "type": "http",
    "url": "https://mcp.supabase.com/mcp",
    "client_id": "your_registered_client_id_here"
  }
}

// Step 3: Save Changes and Restart
- Save the config file and restart Cursor to apply changes.

This correction should ensure that the MCP OAuth flow recognizes the client_id and completes successfully, allowing proper authentication and access token retrieval.

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