Zero-shot just means you give it zero examples. Jev lets you add examples, so it's one-shot/few-shot depending on how many you provide. After playing with it, it seems like once you wonder off their guide examples domains - you have to provide examples to get anything useful from it.

IMO you going to get better results by doing a small tune of a tiny model. Making training dataset for it with LLMs is easy, serving it is going to be cheaper.