diff --git a/modules/ve-mw/dm/nodes/ve.dm.MWExtensionNode.js b/modules/ve-mw/dm/nodes/ve.dm.MWExtensionNode.js
index fff9e4fc2c..c7ee350efa 100644
--- a/modules/ve-mw/dm/nodes/ve.dm.MWExtensionNode.js
+++ b/modules/ve-mw/dm/nodes/ve.dm.MWExtensionNode.js
@@ -13,6 +13,8 @@
  * @mixins ve.dm.GeneratedContentNode
  *
  * @constructor
+ * @param {number} [length] Length of content data (ignored, forced to 0)
+ * @param {Object} [element] Reference to element in linear model
  */
 ve.dm.MWExtensionNode = function VeDmMWExtensionNode( length, element ) {
 	// Parent constructor
diff --git a/modules/ve-mw/dm/nodes/ve.dm.MWMathNode.js b/modules/ve-mw/dm/nodes/ve.dm.MWMathNode.js
index 622f13a96c..c94bda9ab9 100644
--- a/modules/ve-mw/dm/nodes/ve.dm.MWMathNode.js
+++ b/modules/ve-mw/dm/nodes/ve.dm.MWMathNode.js
@@ -12,6 +12,8 @@
  * @extends ve.dm.MWExtensionNode
  *
  * @constructor
+ * @param {number} [length] Length of content data (ignored, forced to 0)
+ * @param {Object} [element] Reference to element in linear model
  */
 ve.dm.MWMathNode = function VeDmMWMathNode( length, element ) {
 	// Parent constructor