How to capture Google Assistant spoken commands

I’ve seen a couple variants of Google Assistant integration, but as far as I can tell, this amounts to essentially exposing devices that are managed/defined in Home Assistant in the Google Home app (so you could, for instance, control a light that you wouldn’t have otherwise been able to control via the Home app).

What I’m looking to do is create a hook to spoken commands to my Google Assistant, such that I can take specific actions from inside a HA automation/service.

Even if this was a “catch-all” endpoint, meaning I would say something like: “Hey Google, tell HomeAssistant XYZ” and my service would simply be delivered “XYZ”, this would still be sufficient to me (although if possible I’d like to be able to provide greater specificity in my spoken commands so the end result is a more specific entry point in my HA code).

Does anything like this exist? Am I thinking about this problem the wrong way?

While I have lots of ways I’d probably put this to use, there is one specific use case I have now: I have recently integrated @dev0’s great Vestaboard custom integration – it’s basically just a network-connected split-flap display that hangs on my wall. I’d like to be able to control the text on my Vestaboard by speaking to my Google Assistant. If I can somehow get an entry point into HA that provides the speech-to-text translation of the command, I could post it to my Vestaboard. But if there’s a better way to accomplish this than what I’m describing, I’m all ears!