Unfortunately, there is no way to send a command to Google Home. There is a DTH but you need to be running another system 24/7 with special software on it.
I’ve been looking for something similar too. Unfortunately I’ve had no luck as of yet.
I’ve got voice working in Python, but the problem is the assistant sdk doesn’t allow for text input yet
I know it’s Node, not Python, but take a look at this: https://github.com/endoplasmic/google-assistant/blob/HEAD/examples/console-input.js
Someone brought the Assistant SDK to Node and that’s an example of a console-only way to interact. I kind of got it working on my Raspberry Pi 3, but haven’t spent much time with it since. From this I think it’d be a webhook away from working decently in a ST setup.
(This would still require a dedicated device running the code)