diff --git a/core/interfaces/i_copyable.js b/core/interfaces/i_copyable.js
index 807911ef9..a20565dc5 100644
--- a/core/interfaces/i_copyable.js
+++ b/core/interfaces/i_copyable.js
@@ -13,8 +13,7 @@
 
 goog.provide('Blockly.ICopyable');
 
-goog.require('Blockly.ISelectable');
-
+goog.requireType('Blockly.ISelectable');
 goog.requireType('Blockly.WorkspaceSvg');
 
 
diff --git a/core/interfaces/i_deletable.js b/core/interfaces/i_deletable.js
index ee3058666..8e8524863 100644
--- a/core/interfaces/i_deletable.js
+++ b/core/interfaces/i_deletable.js
@@ -14,7 +14,10 @@
 goog.provide('Blockly.IDeletable');
 
 
-/** @interface */
+/**
+ * The interface for an object that can be deleted.
+ * @interface
+ */
 Blockly.IDeletable = function() {};
 
 /**
diff --git a/core/interfaces/i_movable.js b/core/interfaces/i_movable.js
index f183cd196..bc0c3bf9f 100644
--- a/core/interfaces/i_movable.js
+++ b/core/interfaces/i_movable.js
@@ -14,7 +14,10 @@
 goog.provide('Blockly.IMovable');
 
 
-/** @interface */
+/**
+ * The interface for an object that is movable.
+ * @interface
+ */
 Blockly.IMovable = function() {};
 
 /**
diff --git a/core/interfaces/i_registrable.js b/core/interfaces/i_registrable.js
index e2803182b..ed989671b 100644
--- a/core/interfaces/i_registrable.js
+++ b/core/interfaces/i_registrable.js
@@ -15,5 +15,8 @@
 goog.provide('Blockly.IRegistrable');
 
 
-/** @interface */
+/**
+ * The interface for a Blockly component that can be registered.
+ * @interface
+ * */
 Blockly.IRegistrable = function() {};
diff --git a/core/interfaces/i_selectable.js b/core/interfaces/i_selectable.js
index 8db8a63f5..e3d817fde 100644
--- a/core/interfaces/i_selectable.js
+++ b/core/interfaces/i_selectable.js
@@ -13,11 +13,12 @@
 
 goog.provide('Blockly.ISelectable');
 
-goog.require('Blockly.IDeletable');
-goog.require('Blockly.IMovable');
+goog.requireType('Blockly.IDeletable');
+goog.requireType('Blockly.IMovable');
 
 
 /**
+ * The interface for an object that is selectable.
  * @extends {Blockly.IDeletable}
  * @extends {Blockly.IMovable}
  * @interface