While some of the downvotes are justified because you're selling this short, I want to point out that your comment about XML is actually valid to a degree. I've found that using XML for prompts lets you annotate specific keywords/phrases and import structure on the prompt which can produce better results.

Getting results back in XML though? That's a terrible idea, you're asking for parsing errors. YML is the best format for getting structured data from LLMs because if there's a parse error you typically only lose the malformed bits.