#257: Added clarification on responses and note about multiple services from the same hook.

Author: brynrhodes

docs/specification/1.0.md

@@ -351,6 +351,10 @@ Below is an example `fhirAuthorization` parameter:
 
 ## CDS Service Response
 
+For successful responses, CDS Services SHALL respond with a 200 HTTP response with an object containing a `cards` element as described below.
+
+> Note that because the CDS client may be invoking multiple services from the same hook, there may be multiple responses related to the same information. This specification does not address these scenarios specifically; both CDS Services and CDS Clients should consider the implications of multiple CDS Services in their integrations.
+
 ### Card Array
 
 Field | Optionality | Type | Description