diff --git a/manifests/messaging/default.pp b/manifests/messaging/default.pp
index 79855be..ec71ef0 100644
--- a/manifests/messaging/default.pp
+++ b/manifests/messaging/default.pp
@@ -14,6 +14,8 @@
 #   (Optional) A URL representing the messaging driver to use
 #   and its full configuration. If not set, we fall back to
 #   the rpc_backend option and driver specific configuration.
+#   Transport URLs take the form:
+#      transport://user:pass@host1:port[,hostN:portN]/virtual_host
 #   (string value)
 #   Defaults to $::os_service_default.
 #
diff --git a/manifests/messaging/notifications.pp b/manifests/messaging/notifications.pp
index 758a430..b9e7e3a 100644
--- a/manifests/messaging/notifications.pp
+++ b/manifests/messaging/notifications.pp
@@ -17,6 +17,8 @@
 #   (Optional) A URL representing the messaging driver to use for
 #   notifications. If not set, we fall back to the same
 #   configuration used for RPC.
+#   Transport URLs take the form::
+#      transport://user:pass@host1:port[,hostN:portN]/virtual_host
 #   (string value)
 #   Defaults to $::os_service_default.
 #