Comment by jcgl

Agree with the other comments about writing OpenAPI by hand. It’s really not that bad at all, and most certainly not “verbose to the point of absurdity.”

Moreover, system boundaries are the best places to invest in being explicit. OpenAPI specs really don’t have that much overhead (especially if you make use of YAML anchors), and are (usually) suitably descriptive to describe the boundary.

In any case, starting with a declarative contract/IDL and doing something like codegen is a great way to go.