Nest provides their own Home/Away status to Stringify, based on their own slightly-obscure logic. I just use it as an input to set Away status in Stringify. If I remember to say "I'm leaving" to Google Home or Alexa on the way out, that sets Stringify's Away status. I could use a geofence as well, but I don't bother with that. If Nest decides with its own logic a couple of hours later that I'm away because it hasn't seen any movement lately, that also sets Stringify's Away status.