diff --git a/google/api/monitored_resource.proto b/google/api/monitored_resource.proto
index 537becdf..3cddbc5c 100644
--- a/google/api/monitored_resource.proto
+++ b/google/api/monitored_resource.proto
@@ -43,12 +43,14 @@ option objc_class_prefix = "GAPI";
 // * The first label of the monitored resource descriptor must be
 //   `resource_container`. There are legacy monitored resource descritptors
 //   start with `project_id`.
-// * It must include a `location` label. * Maximum of default 5 service defined monitored resource descriptors
+// * It must include a `location` label.
+// * Maximum of default 5 service defined monitored resource descriptors
 //   is allowed per service.
 // * Maximum of default 10 labels per monitored resource is allowed.
 //
 // The default maximum limit can be overridden. Please follow
 // https://cloud.google.com/monitoring/quotas
+//
 message MonitoredResourceDescriptor {
   // Optional. The resource name of the monitored resource descriptor:
   // `"projects/{project_id}/monitoredResourceDescriptors/{type}"` where
@@ -58,6 +60,19 @@ message MonitoredResourceDescriptor {
   // resource name format `"monitoredResourceDescriptors/{type}"`.
   string name = 5;
 
+  // Required. The monitored resource type. For example, the type
+  // `cloudsql_database` represents databases in Google Cloud SQL.
+  //
+  // All service defined monitored resource types must be prefixed with the
+  // service name, in the format of `{service name}/{relative resource name}`.
+  // The relative resource name must follow:
+  //
+  // * Only upper and lower-case letters and digits are allowed.
+  // * It must start with upper case character and is recommended to use Upper
+  //   Camel Case style.
+  // * The maximum number of characters allowed for the relative_resource_name
+  //   is 100.
+  //
   // Note there are legacy service monitored resources not following this rule.
   string type = 1;