If its up to this emulator to keep track of changes in Services APIs this is doomed to fail.
I believe AWS already autogenerates their API clients (e.g. boto3) based on some authoritative internal service api spec so I imagine that spec could be used upstream of this tool as well.
Yeah whatever they did internally to get service teams to actually adopt AWS Config ~5 years ago needs to happen here or it’s going to get stuck with marquee services and that’s it. Especially given this is a much much larger ask of each service.