diff --git a/optimizer/src/main/java/dev/cel/optimizer/CelOptimizerOptions.java b/optimizer/src/main/java/dev/cel/optimizer/CelOptimizerOptions.java
index 888683298..292f54224 100644
--- a/optimizer/src/main/java/dev/cel/optimizer/CelOptimizerOptions.java
+++ b/optimizer/src/main/java/dev/cel/optimizer/CelOptimizerOptions.java
@@ -44,7 +44,7 @@ public abstract static class Builder {
 
   /** Returns a new options builder with recommended defaults pre-configured. */
   public static Builder newBuilder() {
-    return new AutoValue_CelOptimizerOptions.Builder().enableAstValidation(false);
+    return new AutoValue_CelOptimizerOptions.Builder().enableAstValidation(true);
   }
 
   CelOptimizerOptions() {}