OpenAPI Overlays for Monetization and Plan Tiering From One Spec

I have watched too many teams maintain three sets of documentation for one API because they sell it three ways. There is the Free tier docs that pretend the premium endpoints do not exist, the Pro tier docs that quote the higher rate limits, and the Enterprise docs that hint at things mere mortals cannot see. All three drift apart within a quarter, because they are copies of copies, hand-edited by whoever drew the short straw that sprint.