I think we need to differentiate between a few things: 1. The specific way different models were trained. Claude was specifically trained with these XML tags

I think we need to differentiate between a few things: 1. The specific way different models were trained. Claude was specifically trained with these XML tags in the input and output. For Claude it works well to say things along the lines of "use a scratchpad for thinking out loud in XML tags first". While you can force GPT to do the same, it may not be as "natural" e.g. high chance of GPT3.5 not doing it. 2. XML tags vs full XML Using XML tags doesn't mean it would be amazing at outputting full valid XML. XML tags are great because there's no further formatting needed within. If you only want to separate sections in your prompt or response, XML tags are perfect for clearly marking start and end, as well as featuring syntax (<>) that's rarely seen in natural text. If it comes to generating a full data schema valid object, my experience is that JSON works way better than XML. It just seems to be a good middle ground between structure while having little overhead. I remember a recent AirBnB posts saying that YAML works even better than JSON. That's not my personal experience. Plus, YAML is something a bit weird and slow on read.