Author here. Short version is that YAML 1.1 behavior has a lot of bad, but the 1.2 spec addressed the major problems (way back in 2009!). I don't really know why PyYAML never updated to 1.2. So for the intervening years Python users kept hitting 1.1 bugs and blaming the format.
t-kalinowskiMay 26, 2026, 1:46 PM
I wonder if YAML is better than JSON for LLMs, because the indentation keeps the nesting level information local to the content.