diff -r a0f15cb8c730 -r 2d0750864a98 chat/shared/src/main/java/org/apidesign/demo/chat/shared/MessageImpl.java
--- a/chat/shared/src/main/java/org/apidesign/demo/chat/shared/MessageImpl.java	Fri Apr 22 05:56:47 2016 +0200
+++ b/chat/shared/src/main/java/org/apidesign/demo/chat/shared/MessageImpl.java	Fri Apr 22 08:53:13 2016 +0200
@@ -51,9 +51,17 @@
         return delta + "min";
     }
 
-    @Model(className = "Query", properties = {
+    @Model(className = "Query", builder = "assign", properties = {
+        @Property(name = "since", type = int.class),
+        @Property(name = "post", type = Message.class),
+    })
+    class QueryCntrl {
+    }
+    
+    @Model(className = "Reply", properties = {
+        @Property(name = "since", type = int.class),
         @Property(name = "messages", type = Message.class, array = true)
     })
-    class QryMsgs {
+    class ReplyCntrl {
     }
 }