The developer of Say Intentions (Brian) has been trying to reach out to you via Discord to look at ways of having a similar outcome achieved by their software. Brian is of the view that GSX could read their flight plan data, or perhaps there is a way to replicate with more reliability what BeyondATC are doing. He has indicated that no response has been received despite several attempts.
We have been discussing this with Brian from SI for more than a year, and there has been many back and forth going on how SI could integrate with GSX.
The LAST I've heard from Brian myself (still in 2024), it seemed to me that SI would do something with data read from GSX airport profiles, and I explained to him something about their format that might not be entirely clear from our SDK. It looked like he understood how it worked and he could proceed without any further help.
Then I stopped hearing from them, now recently somebody reported some comments about not being able to do much because the GSX "API" (double quotes are theirs) wasn't useful for them. Which is puzzling, because not only most of what's in our SDK is there because some developer asked for it, but the BATC folks were able to do what they needed to do with just a very minimal help on my side. They simply emailed my once asking some clarification, and a single reply was everything they needed to integrate BATC and GSX.
Now I hearing from your, for the first time, that is GSX that is supposed to call into SI to do something, and they have an API. That's nice to hear but, it would have been useful if they told me the initial approach that worked for BATC won't work for them, and they want GSX to call SI instead.
The main issue is, I think Brian might assume the GSX channel on Discord is an FSDT-own channel or is an official way of communication. It's not, I'm on Discord only on my spare time, each and every developer we ever worked with, should contact me my email on the FSDT support email, because I'm not constantly on Discord and, in fact, I'll reduce my presence there, because it's seriously impacting productivity and time required to work on actual stuff.