Yeah, thats fair, but if I understood right- this is a custom built tool to be compatible with Ninja.

That work building “yet another build tool” could have gone in to programmatically generating bazel BUILD files. So, there was an active choice here somewhere; we just don’t know all the information as to why effort was diverted away from Bazel and toward building a new tool.

I trust them to make good decisions, so I would like to understand more. :)

Seems like Siso supports Starlark, so maybe its a step in Bazels direction after all.