diff --git a/proto-google-cloud-dialogflow-cx-v3/src/main/java/com/google/cloud/dialogflow/cx/v3/AdvancedSettings.java b/proto-google-cloud-dialogflow-cx-v3/src/main/java/com/google/cloud/dialogflow/cx/v3/AdvancedSettings.java
index 0ebe2a258..8aa91ca91 100644
--- a/proto-google-cloud-dialogflow-cx-v3/src/main/java/com/google/cloud/dialogflow/cx/v3/AdvancedSettings.java
+++ b/proto-google-cloud-dialogflow-cx-v3/src/main/java/com/google/cloud/dialogflow/cx/v3/AdvancedSettings.java
@@ -24,7 +24,12 @@
  * <pre>
  * Hierarchical advanced settings for agent/flow/page/fulfillment/parameter.
  * Settings exposed at lower level overrides the settings exposed at higher
- * level.
+ * level. Overriding occurs at the sub-setting level. For example, the
+ * playback_interruption_settings at fulfillment level only overrides the
+ * playback_interruption_settings at the agent level, leaving other settings
+ * at the agent level unchanged.
+ * DTMF settings does not override each other. DTMF settings set at different
+ * levels define DTMF detections running in parallel.
  * Hierarchy: Agent-&gt;Flow-&gt;Page-&gt;Fulfillment/Parameter.
  * </pre>
  *
@@ -1026,7 +1031,12 @@ protected Builder newBuilderForType(com.google.protobuf.GeneratedMessageV3.Build
    * <pre>
    * Hierarchical advanced settings for agent/flow/page/fulfillment/parameter.
    * Settings exposed at lower level overrides the settings exposed at higher
-   * level.
+   * level. Overriding occurs at the sub-setting level. For example, the
+   * playback_interruption_settings at fulfillment level only overrides the
+   * playback_interruption_settings at the agent level, leaving other settings
+   * at the agent level unchanged.
+   * DTMF settings does not override each other. DTMF settings set at different
+   * levels define DTMF detections running in parallel.
    * Hierarchy: Agent-&gt;Flow-&gt;Page-&gt;Fulfillment/Parameter.
    * </pre>
    *
diff --git a/proto-google-cloud-dialogflow-cx-v3/src/main/java/com/google/cloud/dialogflow/cx/v3/WebhookRequest.java b/proto-google-cloud-dialogflow-cx-v3/src/main/java/com/google/cloud/dialogflow/cx/v3/WebhookRequest.java
index 106548508..5248b95bd 100644
--- a/proto-google-cloud-dialogflow-cx-v3/src/main/java/com/google/cloud/dialogflow/cx/v3/WebhookRequest.java
+++ b/proto-google-cloud-dialogflow-cx-v3/src/main/java/com/google/cloud/dialogflow/cx/v3/WebhookRequest.java
@@ -24,6 +24,8 @@
  * <pre>
  * The request message for a webhook call. The request is sent as a JSON object
  * and the field names will be presented in camel cases.
+ * You may see undocumented fields in an actual request. These fields are used
+ * internally by Dialogflow and should be ignored.
  * </pre>
  *
  * Protobuf type {@code google.cloud.dialogflow.cx.v3.WebhookRequest}
@@ -5409,6 +5411,8 @@ protected Builder newBuilderForType(com.google.protobuf.GeneratedMessageV3.Build
    * <pre>
    * The request message for a webhook call. The request is sent as a JSON object
    * and the field names will be presented in camel cases.
+   * You may see undocumented fields in an actual request. These fields are used
+   * internally by Dialogflow and should be ignored.
    * </pre>
    *
    * Protobuf type {@code google.cloud.dialogflow.cx.v3.WebhookRequest}
diff --git a/proto-google-cloud-dialogflow-cx-v3/src/main/proto/google/cloud/dialogflow/cx/v3/advanced_settings.proto b/proto-google-cloud-dialogflow-cx-v3/src/main/proto/google/cloud/dialogflow/cx/v3/advanced_settings.proto
index 904faab84..d2de5b1fc 100644
--- a/proto-google-cloud-dialogflow-cx-v3/src/main/proto/google/cloud/dialogflow/cx/v3/advanced_settings.proto
+++ b/proto-google-cloud-dialogflow-cx-v3/src/main/proto/google/cloud/dialogflow/cx/v3/advanced_settings.proto
@@ -29,7 +29,13 @@ option ruby_package = "Google::Cloud::Dialogflow::CX::V3";
 
 // Hierarchical advanced settings for agent/flow/page/fulfillment/parameter.
 // Settings exposed at lower level overrides the settings exposed at higher
-// level.
+// level. Overriding occurs at the sub-setting level. For example, the
+// playback_interruption_settings at fulfillment level only overrides the
+// playback_interruption_settings at the agent level, leaving other settings
+// at the agent level unchanged.
+//
+// DTMF settings does not override each other. DTMF settings set at different
+// levels define DTMF detections running in parallel.
 //
 // Hierarchy: Agent->Flow->Page->Fulfillment/Parameter.
 message AdvancedSettings {
diff --git a/proto-google-cloud-dialogflow-cx-v3/src/main/proto/google/cloud/dialogflow/cx/v3/webhook.proto b/proto-google-cloud-dialogflow-cx-v3/src/main/proto/google/cloud/dialogflow/cx/v3/webhook.proto
index 0f20d698a..7974131d7 100644
--- a/proto-google-cloud-dialogflow-cx-v3/src/main/proto/google/cloud/dialogflow/cx/v3/webhook.proto
+++ b/proto-google-cloud-dialogflow-cx-v3/src/main/proto/google/cloud/dialogflow/cx/v3/webhook.proto
@@ -273,6 +273,9 @@ message DeleteWebhookRequest {
 
 // The request message for a webhook call. The request is sent as a JSON object
 // and the field names will be presented in camel cases.
+//
+// You may see undocumented fields in an actual request. These fields are used
+// internally by Dialogflow and should be ignored.
 message WebhookRequest {
   // Represents fulfillment information communicated to the webhook.
   message FulfillmentInfo {