Many interoperability assumptions depend on knowing if the systems involved in the information exchange do or do not support certains CDS Hooks. A system's support for CDS Hooks currently is not publically reported anywhere, thus it is kept secret. (Grahame Grieve, 5/13/2018, "If it isn't public, it is secret!.") Thus, we need a way to require systems to assert CDS Hooks that it supports publically, to advance the efforts of interoperability.