diff --git a/google/pubsub/v1/pubsub.proto b/google/pubsub/v1/pubsub.proto
index b542351d9d..95dd7f829c 100644
--- a/google/pubsub/v1/pubsub.proto
+++ b/google/pubsub/v1/pubsub.proto
@@ -847,13 +847,16 @@ message Topic {
     INGESTION_RESOURCE_ERROR = 2;
   }
 
-  // Required. The name of the topic. It must have the format
+  // Required. Identifier. The name of the topic. It must have the format
   // `"projects/{project}/topics/{topic}"`. `{topic}` must start with a letter,
   // and contain only letters (`[A-Za-z]`), numbers (`[0-9]`), dashes (`-`),
   // underscores (`_`), periods (`.`), tildes (`~`), plus (`+`) or percent
   // signs (`%`). It must be between 3 and 255 characters in length, and it
   // must not start with `"goog"`.
-  string name = 1 [(google.api.field_behavior) = REQUIRED];
+  string name = 1 [
+    (google.api.field_behavior) = REQUIRED,
+    (google.api.field_behavior) = IDENTIFIER
+  ];
 
   // Optional. See [Creating and managing labels]
   // (https://cloud.google.com/pubsub/docs/labels).
@@ -960,10 +963,11 @@ message PubsubMessage {
 
 // Request for the GetTopic method.
 message GetTopicRequest {
-  // Required. The name of the topic to get.
+  // Required. Identifier. The name of the topic to get.
   // Format is `projects/{project}/topics/{topic}`.
   string topic = 1 [
     (google.api.field_behavior) = REQUIRED,
+    (google.api.field_behavior) = IDENTIFIER,
     (google.api.resource_reference) = { type: "pubsub.googleapis.com/Topic" }
   ];
 }
@@ -984,10 +988,11 @@ message UpdateTopicRequest {
 
 // Request for the Publish method.
 message PublishRequest {
-  // Required. The messages in the request will be published on this topic.
-  // Format is `projects/{project}/topics/{topic}`.
+  // Required. Identifier. The messages in the request will be published on this
+  // topic. Format is `projects/{project}/topics/{topic}`.
   string topic = 1 [
     (google.api.field_behavior) = REQUIRED,
+    (google.api.field_behavior) = IDENTIFIER,
     (google.api.resource_reference) = { type: "pubsub.googleapis.com/Topic" }
   ];
 
@@ -1005,10 +1010,11 @@ message PublishResponse {
 
 // Request for the `ListTopics` method.
 message ListTopicsRequest {
-  // Required. The name of the project in which to list topics.
+  // Required. Identifier. The name of the project in which to list topics.
   // Format is `projects/{project-id}`.
   string project = 1 [
     (google.api.field_behavior) = REQUIRED,
+    (google.api.field_behavior) = IDENTIFIER,
     (google.api.resource_reference) = {
       type: "cloudresourcemanager.googleapis.com/Project"
     }
@@ -1102,10 +1108,11 @@ message ListTopicSnapshotsResponse {
 
 // Request for the `DeleteTopic` method.
 message DeleteTopicRequest {
-  // Required. Name of the topic to delete.
+  // Required. Identifier. Name of the topic to delete.
   // Format is `projects/{project}/topics/{topic}`.
   string topic = 1 [
     (google.api.field_behavior) = REQUIRED,
+    (google.api.field_behavior) = IDENTIFIER,
     (google.api.resource_reference) = { type: "pubsub.googleapis.com/Topic" }
   ];
 }
@@ -1399,13 +1406,16 @@ message Subscription {
     string subscription = 2 [(google.api.field_behavior) = OPTIONAL];
   }
 
-  // Required. The name of the subscription. It must have the format
+  // Required. Identifier. The name of the subscription. It must have the format
   // `"projects/{project}/subscriptions/{subscription}"`. `{subscription}` must
   // start with a letter, and contain only letters (`[A-Za-z]`), numbers
   // (`[0-9]`), dashes (`-`), underscores (`_`), periods (`.`), tildes (`~`),
   // plus (`+`) or percent signs (`%`). It must be between 3 and 255 characters
   // in length, and it must not start with `"goog"`.
-  string name = 1 [(google.api.field_behavior) = REQUIRED];
+  string name = 1 [
+    (google.api.field_behavior) = REQUIRED,
+    (google.api.field_behavior) = IDENTIFIER
+  ];
 
   // Required. The name of the topic from which this subscription is receiving
   // messages. Format is `projects/{project}/topics/{topic}`. The value of this
@@ -1934,10 +1944,11 @@ message ReceivedMessage {
 
 // Request for the GetSubscription method.
 message GetSubscriptionRequest {
-  // Required. The name of the subscription to get.
+  // Required. Identifier. The name of the subscription to get.
   // Format is `projects/{project}/subscriptions/{sub}`.
   string subscription = 1 [
     (google.api.field_behavior) = REQUIRED,
+    (google.api.field_behavior) = IDENTIFIER,
     (google.api.resource_reference) = {
       type: "pubsub.googleapis.com/Subscription"
     }
@@ -1957,10 +1968,11 @@ message UpdateSubscriptionRequest {
 
 // Request for the `ListSubscriptions` method.
 message ListSubscriptionsRequest {
-  // Required. The name of the project in which to list subscriptions.
-  // Format is `projects/{project-id}`.
+  // Required. Identifier. The name of the project in which to list
+  // subscriptions. Format is `projects/{project-id}`.
   string project = 1 [
     (google.api.field_behavior) = REQUIRED,
+    (google.api.field_behavior) = IDENTIFIER,
     (google.api.resource_reference) = {
       type: "cloudresourcemanager.googleapis.com/Project"
     }
@@ -1989,10 +2001,11 @@ message ListSubscriptionsResponse {
 
 // Request for the DeleteSubscription method.
 message DeleteSubscriptionRequest {
-  // Required. The subscription to delete.
+  // Required. Identifier. The subscription to delete.
   // Format is `projects/{project}/subscriptions/{sub}`.
   string subscription = 1 [
     (google.api.field_behavior) = REQUIRED,
+    (google.api.field_behavior) = IDENTIFIER,
     (google.api.resource_reference) = {
       type: "pubsub.googleapis.com/Subscription"
     }
@@ -2260,14 +2273,15 @@ message StreamingPullResponse {
 
 // Request for the `CreateSnapshot` method.
 message CreateSnapshotRequest {
-  // Required. User-provided name for this snapshot. If the name is not provided
-  // in the request, the server will assign a random name for this snapshot on
-  // the same project as the subscription. Note that for REST API requests, you
-  // must specify a name.  See the [resource name
+  // Required. Identifier. User-provided name for this snapshot. If the name is
+  // not provided in the request, the server will assign a random name for this
+  // snapshot on the same project as the subscription. Note that for REST API
+  // requests, you must specify a name.  See the [resource name
   // rules](https://cloud.google.com/pubsub/docs/pubsub-basics#resource_names).
   // Format is `projects/{project}/snapshots/{snap}`.
   string name = 1 [
     (google.api.field_behavior) = REQUIRED,
+    (google.api.field_behavior) = IDENTIFIER,
     (google.api.resource_reference) = { type: "pubsub.googleapis.com/Snapshot" }
   ];
 
@@ -2356,20 +2370,22 @@ message Snapshot {
 
 // Request for the GetSnapshot method.
 message GetSnapshotRequest {
-  // Required. The name of the snapshot to get.
+  // Required. Identifier. The name of the snapshot to get.
   // Format is `projects/{project}/snapshots/{snap}`.
   string snapshot = 1 [
     (google.api.field_behavior) = REQUIRED,
+    (google.api.field_behavior) = IDENTIFIER,
     (google.api.resource_reference) = { type: "pubsub.googleapis.com/Snapshot" }
   ];
 }
 
 // Request for the `ListSnapshots` method.
 message ListSnapshotsRequest {
-  // Required. The name of the project in which to list snapshots.
+  // Required. Identifier. The name of the project in which to list snapshots.
   // Format is `projects/{project-id}`.
   string project = 1 [
     (google.api.field_behavior) = REQUIRED,
+    (google.api.field_behavior) = IDENTIFIER,
     (google.api.resource_reference) = {
       type: "cloudresourcemanager.googleapis.com/Project"
     }
@@ -2397,10 +2413,11 @@ message ListSnapshotsResponse {
 
 // Request for the `DeleteSnapshot` method.
 message DeleteSnapshotRequest {
-  // Required. The name of the snapshot to delete.
+  // Required. Identifier. The name of the snapshot to delete.
   // Format is `projects/{project}/snapshots/{snap}`.
   string snapshot = 1 [
     (google.api.field_behavior) = REQUIRED,
+    (google.api.field_behavior) = IDENTIFIER,
     (google.api.resource_reference) = { type: "pubsub.googleapis.com/Snapshot" }
   ];
 }