Really interesting use of intents and entities. I feel like some of this is reinventing the wheel, since there is already a grammar specification, but novel use of intents/entities. https://www.w3.org/TR/speech-grammar/
Edit - Sorry, I realize that's a tangent. What I'm saying is that when I was evaluating speech to text engines for things like IVR systems using AWS and Google, neither of them supported SRGS. Microsoft does, I think, but they didn't have a telephony component, and IBM was ignored from the get go, so "no one" really means "two very large companies."
I would have preferred to use a standard. Perhaps this is something for a future version.