When I open the Google Home app, I can see that it suggests connecting to smart home apps that I have installed on my Android or iOS device.
I'm working on an app that has a published Smart Home integration, but it does not show as a suggestion. I couldn't find any documentation on how to make it available as a suggestion like these ones on the image bellow.
The suggestion is what Google calls App Discovery
, and there is new documentation talking about it here:
https://developers.google.com/assistant/smarthome/develop/discovery
It requires linking a website and an android app to your Smart Home Skill.