Yeah, but I tried switching to minified JSON on a semantic labelling task and saw a ~5% accuracy drop.

I suspect this happened because most of the pre-training corpus was pretty-printed JSON, and the LLM was forced to derail from likely path and also lost all "visual cues" of nesting depth.

This might happen here too, but maybe to a lesser extent. Anyways, I'll stop building castles in the air now and try it sometime.

if you really care about structured output switch to XML. much better results, which is why all AI providers tend to use pseudo-xml in their system prompts and tool definitions