diff --git a/lib/class.js b/lib/class.js
index 6ab2544..e9ead69 100644
--- a/lib/class.js
+++ b/lib/class.js
@@ -353,14 +353,10 @@ function createImplement( base, ifaces, cname )
 function extend()
 {
     // set up the new class
-    var data = class_builder.build.apply( null, arguments ),
+    var new_class = class_builder.build.apply( null, arguments );
 
-        new_class = data[ 'class' ],
-        class_id  = data.classId
-    ;
-
-    // important: call after setting prototype
-    setupProps( new_class, class_id );
+    // set up some additional convenience props
+    setupProps( new_class );
 
     // lock down the new class (if supported) to ensure that we can't add
     // members at runtime
@@ -418,16 +414,14 @@ var implement = function()
 /**
  * Sets up common properties for the provided function (class)
  *
- * @param  {function()}  func      function (class) to set up
- * @param  {number}      class_id  unique id to assign to class
+ * @param  {function()}  func  function (class) to set up
  *
  * @return  {undefined}
  */
-function setupProps( func, class_id )
+function setupProps( func )
 {
     attachExtend( func );
     attachImplement( func );
-    attachId( func, class_id );
 }
 
 
@@ -477,22 +471,3 @@ function attachImplement( func )
     });
 }
 
-
-/**
- * Attaches the unique id to the class and its prototype
- *
- * The unique identifier is used internally to match a class and its instances
- * with the class metadata. Exposing the id breaks encapsulation to a degree,
- * but is a lesser evil when compared to exposing all metadata.
- *
- * @param  {Function}  func  function (class) to attach method to
- * @param  {number}    id    id to assign
- *
- * @return  {undefined}
- */
-function attachId( func, id )
-{
-    util.defineSecureProp( func, '__cid', id );
-    util.defineSecureProp( func.prototype, '__cid', id );
-}
-
diff --git a/lib/class_builder.js b/lib/class_builder.js
index cb1e52a..f06b299 100644
--- a/lib/class_builder.js
+++ b/lib/class_builder.js
@@ -217,14 +217,12 @@ exports.build = function extend()
     meta.name            = cname;
 
     attachAbstract( new_class, abstract_methods );
+    attachId( new_class, class_id );
 
     // we're done with the extension process
     extending = false;
 
-    return {
-        'class': new_class,
-        classId: class_id,
-    };
+    return new_class;
 };
 
 
@@ -752,3 +750,22 @@ function attachAbstract( func, methods )
     });
 }
 
+
+/**
+ * Attaches the unique id to the class and its prototype
+ *
+ * The unique identifier is used internally to match a class and its instances
+ * with the class metadata. Exposing the id breaks encapsulation to a degree,
+ * but is a lesser evil when compared to exposing all metadata.
+ *
+ * @param  {function()}  ctor  constructor (class) to attach method to
+ * @param  {number}      id    id to assign
+ *
+ * @return  {undefined}
+ */
+function attachId( ctor, id )
+{
+    util.defineSecureProp( ctor, '__cid', id );
+    util.defineSecureProp( ctor.prototype, '__cid', id );
+}
+