When it comes to generating a custom assistant I have not been able to use most of the voices that are available through the Vapi dashboard assistant setup. The only voices that work are the basic ones listed in
https://api.vapi.ai/api#/ (see
playhtvoice in the schemas section at the bottom). For example, I setup an assistant in the dashboard using PlayHT's "Autumn" voice (which works), but this doesn't work if I generate the assistant with a web snippet — in that case I have had to use "donna" instead. If I use "autumn" or "Autumn" it allows me to call but there is no voice and it hangs up a few seconds later.