diff --git a/api-ref/source/v3/parameters.yaml b/api-ref/source/v3/parameters.yaml
index 12206857c8..b3f1a2e32a 100644
--- a/api-ref/source/v3/parameters.yaml
+++ b/api-ref/source/v3/parameters.yaml
@@ -889,7 +889,10 @@ group_domain_id:
   type: string
 group_domain_id_request_body:
   description: |
-    The ID of the domain of the group.
+    The ID of the domain of the group. If the domain ID is not
+    provided in the request, the Identity service will attempt to
+    pull the domain ID from the token used in the request. Note that
+    this requires the use of a domain-scoped token.
   in: body
   required: false
   type: string
@@ -1473,7 +1476,10 @@ user_domain_id:
   type: string
 user_domain_id_request_body:
   description: |
-    The ID of the domain for the user.
+    The ID of the domain of the user. If the domain ID is not
+    provided in the request, the Identity service will attempt to
+    pull the domain ID from the token used in the request. Note that
+    this requires the use of a domain-scoped token.
   in: body
   required: false
   type: string