Fediverse… Fed… Federated. Unifying it would defeat the purpose. Yes, there could be a single platform, with federated hosting, but multiple platforms working with a single protocol is a good thing.
Consider the web - in the old days, it was an open platform. Then Internet Explorer got a stranglehold, and to use the web practically required using IE on Windows (many sites did not work in other browsers). Eventually we righted the ship, but now Chromium browsers are taking over, and we’re heading in a similar direction.
For the fediverse to remain open and effective, we should embrace extra platforms*. It prevents anyone getting too much control over the protocol, prevents lock-in, prevents centralization, etc.
*We should generally encourage use/development of the same protocol, though.









I don’t have as much experience with HASS, but I did use Mycroft for quite a while (stopped only because I had multiple big moves, and ended up in a place small enough voice control didn’t really make sense any more). There were a few intent parsers used with/made for that:
https://github.com/MycroftAI/adapt https://github.com/MycroftAI/padatious https://github.com/MycroftAI/padaos
In my experience, Adapt was far and away the most reliable. If you go the route of rolling your own solution, I’d recommend checking that out, and using the absolute minimum number of words to design your intents. E.g. require “off” and an entity, and nothing else, so that “AC off,” “turn off the AC,” and “turn the AC off” all work. This reduces the number of words your STT has to transcribe correctly, and allows flexibility in command phrasing.
If you borrow a little more from Mycroft, they had “fallback” skills that were triggered when an intent couldn’t be matched. You could use the same idea, and use https://github.com/seatgeek/thefuzz to fuzzy match entities and keywords, to try to handle remaining cases where STT fails. I believe that is what this community made skill attempted to do: https://github.com/MycroftAI/skill-homeassistant (I think there were more than one HASS skill implementations, so I could be conflating this with another).
Another comment mentioned OVOS/Neon - those forked off of Mycroft, so you may see overlap if you investigate those as well.