New in draft 7

The$commentkeyword is strictly intended for adding comments to aschema. Its value must always be a string. Unlike the annotationstitle,description, andexamples, JSON schemaimplementationsaren't allowed to attach any meaning or behavior to it whatsoever, andmay even strip them at any time. Therefore, they are useful for leavingnotes to future editors of a JSON schema, but should not be used tocommunicate to users of the schema.

data

{"$comment":"Created by John Doe","type":"object","properties":{"country":{"$comment":"TODO: add enum of countries"}}}