diff --git a/packages/k8s.contrib.crd/PklProject b/packages/k8s.contrib.crd/PklProject
index 33fd01b..6e1d730 100644
--- a/packages/k8s.contrib.crd/PklProject
+++ b/packages/k8s.contrib.crd/PklProject
@@ -29,5 +29,5 @@ dependencies {
 }
 
 package {
-  version = "2.0.1"
+  version = "2.0.2"
 }
diff --git a/packages/k8s.contrib.crd/PklProject.deps.json b/packages/k8s.contrib.crd/PklProject.deps.json
index 58e1781..fa3beab 100644
--- a/packages/k8s.contrib.crd/PklProject.deps.json
+++ b/packages/k8s.contrib.crd/PklProject.deps.json
@@ -15,12 +15,12 @@
     },
     "package://pkg.pkl-lang.org/pkl-pantry/org.json_schema.contrib@1": {
       "type": "local",
-      "uri": "projectpackage://pkg.pkl-lang.org/pkl-pantry/org.json_schema.contrib@1.1.3",
+      "uri": "projectpackage://pkg.pkl-lang.org/pkl-pantry/org.json_schema.contrib@1.1.4",
       "path": "../org.json_schema.contrib"
     },
     "package://pkg.pkl-lang.org/pkl-pantry/pkl.experimental.syntax@1": {
       "type": "local",
-      "uri": "projectpackage://pkg.pkl-lang.org/pkl-pantry/pkl.experimental.syntax@1.0.3",
+      "uri": "projectpackage://pkg.pkl-lang.org/pkl-pantry/pkl.experimental.syntax@1.1.0",
       "path": "../pkl.experimental.syntax"
     },
     "package://pkg.pkl-lang.org/pkl-pantry/pkl.experimental.uri@1": {
diff --git a/packages/org.json_schema.contrib/PklProject b/packages/org.json_schema.contrib/PklProject
index 1464113..0479f1c 100644
--- a/packages/org.json_schema.contrib/PklProject
+++ b/packages/org.json_schema.contrib/PklProject
@@ -25,5 +25,5 @@ dependencies {
 }
 
 package {
-  version = "1.1.3"
+  version = "1.1.4"
 }
diff --git a/packages/org.json_schema.contrib/PklProject.deps.json b/packages/org.json_schema.contrib/PklProject.deps.json
index 3ffa263..d025a51 100644
--- a/packages/org.json_schema.contrib/PklProject.deps.json
+++ b/packages/org.json_schema.contrib/PklProject.deps.json
@@ -3,7 +3,7 @@
   "resolvedDependencies": {
     "package://pkg.pkl-lang.org/pkl-pantry/pkl.experimental.syntax@1": {
       "type": "local",
-      "uri": "projectpackage://pkg.pkl-lang.org/pkl-pantry/pkl.experimental.syntax@1.0.3",
+      "uri": "projectpackage://pkg.pkl-lang.org/pkl-pantry/pkl.experimental.syntax@1.1.0",
       "path": "../pkl.experimental.syntax"
     },
     "package://pkg.pkl-lang.org/pkl-pantry/pkl.experimental.uri@1": {
diff --git a/packages/pkl.experimental.syntax/PklProject b/packages/pkl.experimental.syntax/PklProject
index 675c147..13f5f9c 100644
--- a/packages/pkl.experimental.syntax/PklProject
+++ b/packages/pkl.experimental.syntax/PklProject
@@ -1,5 +1,5 @@
 //===----------------------------------------------------------------------===//
-// Copyright © 2024 Apple Inc. and the Pkl project authors. All rights reserved.
+// Copyright © 2024-2025 Apple Inc. and the Pkl project authors. All rights reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -17,6 +17,6 @@
 amends "../basePklProject.pkl"
 
 package {
-  version = "1.0.3"
+  version = "1.1.0"
   apiTests = import*("tests/*.pkl").keys.toListing()
 }
diff --git a/packages/pkl.experimental.syntax/TypeNode.pkl b/packages/pkl.experimental.syntax/TypeNode.pkl
index f57f0c5..55272e3 100644
--- a/packages/pkl.experimental.syntax/TypeNode.pkl
+++ b/packages/pkl.experimental.syntax/TypeNode.pkl
@@ -1,5 +1,5 @@
 //===----------------------------------------------------------------------===//
-// Copyright © 2024 Apple Inc. and the Pkl project authors. All rights reserved.
+// Copyright © 2024-2025 Apple Inc. and the Pkl project authors. All rights reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -20,6 +20,7 @@ extends "Node.pkl"
 import "QualifiedIdentifierNode.pkl"
 import "ExpressionNode.pkl"
 import "TypeNode.pkl"
+import "Node.pkl"
 
 class NullableTypeNode extends TypeNode {
   typeNode: TypeNode
@@ -65,8 +66,17 @@ class ConstrainedTypeNode extends TypeNode {
       renderedUnderlyingType + renderConstraints(currentIndent)
 }
 
+class UnionDefaultType extends Node {
+  typeNode: TypeNode
+
+  function render(currentIndent: String) = "*\(typeNode.render(currentIndent))"
+}
+
 class UnionTypeNode extends TypeNode {
-  members: Listing<TypeNode>
+  members: Listing<TypeNode|UnionDefaultType>(atMostOneUnionDefaultType)
+
+  const local atMostOneUnionDefaultType = (members: Listing<TypeNode|UnionDefaultType>) ->
+      members.fold(0, (acc, member) -> acc + if (member is UnionDefaultType) 1 else 0) <= 1
 
   function render(currentIndent: String) =
     let (childrenRendered = members.toList().map((t) -> t.render(currentIndent)))
diff --git a/packages/pkl.experimental.syntax/tests/TypeNode.pkl b/packages/pkl.experimental.syntax/tests/TypeNode.pkl
index 0acc38f..b3377e6 100644
--- a/packages/pkl.experimental.syntax/tests/TypeNode.pkl
+++ b/packages/pkl.experimental.syntax/tests/TypeNode.pkl
@@ -1,5 +1,5 @@
 //===----------------------------------------------------------------------===//
-// Copyright © 2024 Apple Inc. and the Pkl project authors. All rights reserved.
+// Copyright © 2024-2025 Apple Inc. and the Pkl project authors. All rights reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -106,5 +106,37 @@ facts {
     }.render("") == """
       "one"|"two"
       """
+
+    new TypeNode.UnionTypeNode {
+      members {
+        new TypeNode.UnionDefaultType {
+          typeNode = new TypeNode.StringLiteralTypeNode {
+            value = "one"
+          }
+        }
+        new TypeNode.StringLiteralTypeNode {
+          value = "two"
+        }
+      }
+    }.render("") == """
+      *"one"|"two"
+      """
+
+    module.catch(() ->
+      new TypeNode.UnionTypeNode {
+        members {
+          new TypeNode.UnionDefaultType {
+            typeNode = new TypeNode.StringLiteralTypeNode {
+              value = "one"
+            }
+          }
+          new TypeNode.UnionDefaultType {
+            typeNode = new TypeNode.StringLiteralTypeNode {
+              value = "two"
+            }
+          }
+        }
+      }.render("")
+    ).startsWith("Type constraint `atMostOneUnionDefaultType` violated.")
   }
 }