Shared Folder Metadata

It looks like you're referring to the Core API /shared_folders endpoint. The documentation means that if shared_folder_id is specified, you must also specify include_membership. However, that doesn't mean you can't use include_membership without a shared_folder_id. That means you can call /shared_folders and set include_membership=true without specifying a shared_folder_id, and it will return all of the shared folders along with the membership.

I just tried that and it worked for me. Give that a try and let me know if you run in to any trouble.