I'm currently working on a contact management app and I've been trying to understand how I can enable my app to provide suggestions in the Mail.app under "Siri Found In Apps". I began down the path of exposing my contacts via Spotlight Core but that doesn't seem to expose them to Mail.app. I started investigating using SiriKit, but my app doesn't match any of the allowed intents. NSUserActivity, also doesn't feel like the right thing since I would like to expose all of my contacts, not just the one that I've recently visited.
Is it possible for a non-apple app to provide suggestions when typing a recipient email in Mail.app? (I haven't found any 3rd party apps yet)
If it is, could you please point me in the correct direction to enable this functionality?
Is there way to enable this functionality in the Phone app as well?