diff --git a/draft-ietf-oauth-client-id-metadata-document.md b/draft-ietf-oauth-client-id-metadata-document.md
index dcbd13e..c242fbd 100644
--- a/draft-ietf-oauth-client-id-metadata-document.md
+++ b/draft-ietf-oauth-client-id-metadata-document.md
@@ -197,6 +197,13 @@ To enable developers to author applications on their machines, without exposing
 A Client ID Metadata Document Service is a web service through which developers can acquire a stable URL to a Client ID Metadata Document. This service MAY expire clients from time to time, and MAY require developers to provide additional information about the client being developed.
 
 
+The only requirement on Client ID Metadata Document Services is that they MUST
+return valid Client ID Metadata Documents for the `client_id`s that they
+provision, or return a status code indicating an error response (e.g., 404 Not
+Found). How a Client ID Metadata Document Service creates or stores metadata
+documents is outside of the scope of this document.
+
+
 By providing at least one Client ID Metadata Document Service, an authorization server can enable developers to create applications, and still indicate to non-technical people that the client that they are about to authorize is currently under-development and may not be trustworthy or secure.
 
 ## Metadata Discovery Errors