How to detect SSO login in PHP AUth0 SDK

How do i detect the sso login session from other application in my second application which is in PHP and uses the Auth0 SDK?

From what i’ve tested it only detects when i actually try to visit the $auth0->login() url.
If i dont visit that it wont know at all.

Is it possible to curl the authorize endpoint and determine i have a session or something?