Why Cursor says "OAuth provider initialized" and then goes silent (MCP OAuth discovery)

I'm Jane, and I work on Publora. We build an MCP server for social publishing.

Thought I'd share a debugging story in case it saves someone else a day.

We built a one-click "Add to Cursor" button. The button took twenty minutes. Then Cursor printed "OAuth provider initialized" and stopped. No error. No popup. Nothing.

We spent most of a day blaming the API key.

It wasn't the key.

With a placeholder key, our server correctly returned 401. Cursor fell back to OAuth discovery, requested /.well-known/oauth-authorization-server, and the response we served wasn't in the format the spec expects. Cursor couldn't parse it and quietly gave up.

The fix was boring. Serve proper OAuth metadata: issuer, authorization endpoint, token endpoint, client registration, PKCE. After that it just worked. Click, sign in, connected.

The takeaway for me was simple: if an MCP client says "OAuth provider initialized" and then goes silent, check your discovery document before you debug anything else. In our case, /.well-known/oauth-authorization-server was the culprit, not the credentials.

One question for other builders here: how are you handling MCP OAuth across clients? Cursor, Claude, and VS Code all behave a little differently during discovery, and I'm curious what issues you've run into.