Hello-
I'd like to suggest that we add actions to our message templates so that the action buttons appear in the subject line of our customer's inboxes:
OrderPlaced.CustomerNotification
https://developers.google.com/gmail/markup/reference/order
ShipmentSent.CustomerNotification
https://developers.google.com/gmail/markup/reference/parcel-delivery
...or maybe just this one:
https://developers.google.com/gmail/markup/reference/go-to-action#track_action
Thanks!