diff --git a/core/src/main/java/com/google/adk/tools/ToolConfirmation.java b/core/src/main/java/com/google/adk/tools/ToolConfirmation.java
index 8a588b52..4d74af2c 100644
--- a/core/src/main/java/com/google/adk/tools/ToolConfirmation.java
+++ b/core/src/main/java/com/google/adk/tools/ToolConfirmation.java
@@ -19,6 +19,7 @@
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
+import com.google.adk.JsonBaseModel;
 import com.google.auto.value.AutoValue;
 import com.google.errorprone.annotations.CanIgnoreReturnValue;
 import javax.annotation.Nullable;
@@ -26,7 +27,7 @@
 /** Represents a tool confirmation configuration. */
 @AutoValue
 @JsonDeserialize(builder = ToolConfirmation.Builder.class)
-public abstract class ToolConfirmation {
+public abstract class ToolConfirmation extends JsonBaseModel {
 
   @Nullable
   @JsonProperty("hint")