How to 'expose' ST device info to Google Home?

How can I ‘expose’ ST device info to Google Home. As an example, I have a basic Samsung Multi-Sensor which I use mainly to control lights with SmartLighting based on open/closed status. However, this device also reports the temperature. Is there a way to ‘expose’ this device info so that I can ask Google Home what the temperate is ‘at the back door’? Can I create a virtual thermostat that receives this info from the Multi-Sensor but that Google Home sees as a thermostat device type?

A different way to ask…how does Google Home know what the device type is and what info it reports or responds to?