diff --git a/packages/google-cloud-ces/protos/google/cloud/ces/v1beta/deployment.proto b/packages/google-cloud-ces/protos/google/cloud/ces/v1beta/deployment.proto
index 988fefd735f..9df98b98e32 100644
--- a/packages/google-cloud-ces/protos/google/cloud/ces/v1beta/deployment.proto
+++ b/packages/google-cloud-ces/protos/google/cloud/ces/v1beta/deployment.proto
@@ -38,17 +38,19 @@ message Deployment {
 
   // Identifier. The resource name of the deployment.
   // Format:
-  // projects/{project}/locations/{location}/apps/{app}/deployments/{deployment}
+  // `projects/{project}/locations/{location}/apps/{app}/deployments/{deployment}`
   string name = 1 [(google.api.field_behavior) = IDENTIFIER];
 
   // Required. Display name of the deployment.
   string display_name = 8 [(google.api.field_behavior) = REQUIRED];
 
-  // Required. The resource name of the app version to deploy.
+  // Optional. The resource name of the app version to deploy.
   // Format:
-  // projects/{project}/locations/{location}/apps/{app}/versions/{version}
+  // `projects/{project}/locations/{location}/apps/{app}/versions/{version}`
+  // Use `projects/{project}/locations/{location}/apps/{app}/versions/-` to use
+  // the draft app.
   string app_version = 2 [
-    (google.api.field_behavior) = REQUIRED,
+    (google.api.field_behavior) = OPTIONAL,
     (google.api.resource_reference) = { type: "ces.googleapis.com/AppVersion" }
   ];
 
diff --git a/packages/google-cloud-ces/protos/google/cloud/ces/v1beta/session_service.proto b/packages/google-cloud-ces/protos/google/cloud/ces/v1beta/session_service.proto
index d6d235d4902..b0ab0ccdf87 100644
--- a/packages/google-cloud-ces/protos/google/cloud/ces/v1beta/session_service.proto
+++ b/packages/google-cloud-ces/protos/google/cloud/ces/v1beta/session_service.proto
@@ -445,7 +445,7 @@ message BidiSessionServerMessage {
     RecognitionResult recognition_result = 2
         [(google.api.field_behavior) = OPTIONAL];
 
-    // Optional. Interruption signal detected from the audio input.
+    // Optional. Indicates the agent's audio response has been interrupted.
     InterruptionSignal interruption_signal = 3
         [(google.api.field_behavior) = OPTIONAL];
 
diff --git a/packages/google-cloud-ces/protos/protos.json b/packages/google-cloud-ces/protos/protos.json
index 201e3b6d4d3..01ab37ffa53 100644
--- a/packages/google-cloud-ces/protos/protos.json
+++ b/packages/google-cloud-ces/protos/protos.json
@@ -14846,7 +14846,7 @@
                           "type": "string",
                           "id": 2,
                           "options": {
-                            "(google.api.field_behavior)": "REQUIRED",
+                            "(google.api.field_behavior)": "OPTIONAL",
                             "(google.api.resource_reference).type": "ces.googleapis.com/AppVersion"
                           }
                         },