I've noticed that, when using the MCC, you have to specify the clientEmail header ( http://www.google.com/apis/adwords/developer/index.html#adwords_api_intro_headers ). However, there doesn't appear to be a way to retrieve all client account email IDs from any of the already published services.

Does Google have a service for this and I'm unaware of it? If not, does Google plan to publish said service?

My goal is to write code that will introspect the remote API without having to update the client list on our side of things.