This needs a side-by-side config comparison with something like echarts config schema format. I really don't see the point.

I'm 99% sure the verbosity required in the system prompt to teach non-M$ models this new ever-so-slightly-different-but-not-obviously-necessary chart def abstraction format, and the iterations required to get it right, will outweigh any supposed efficiency gains resulting from using it.

Just stating the obvious.