Awesome! I think serial builds should be fairly simple to implement if you can tie it back to a transaction in a data store.

I get the DSL desire, and I feel I've already lost the "YAML is fine" battle elsewhere so that's not a problem. I think a language like jsonnet or cue would have been a better choice simply because they don't involve users learning a new language or you from implementing a new language. Both would have allowed plugging in your own standard library of functions and abstractions.