diff --git a/libraries/stdlib/common/src/kotlin/collections/AbstractMutableList.kt b/libraries/stdlib/common/src/kotlin/collections/AbstractMutableList.kt
index 515fc4775b9..3864de20db9 100644
--- a/libraries/stdlib/common/src/kotlin/collections/AbstractMutableList.kt
+++ b/libraries/stdlib/common/src/kotlin/collections/AbstractMutableList.kt
@@ -22,6 +22,11 @@ expect abstract class AbstractMutableList<E> : MutableList<E> {
 
     // From MutableList
 
+    /**
+     * Adds the specified element to the end of this list.
+     *
+     * @return `true` because the list is always modified as the result of this operation.
+     */
     override fun add(element: E): Boolean
     override fun remove(element: E): Boolean
     override fun addAll(elements: Collection<E>): Boolean
diff --git a/libraries/stdlib/js/src/kotlin/collections/AbstractMutableList.kt b/libraries/stdlib/js/src/kotlin/collections/AbstractMutableList.kt
index 11278919d17..cef22961017 100644
--- a/libraries/stdlib/js/src/kotlin/collections/AbstractMutableList.kt
+++ b/libraries/stdlib/js/src/kotlin/collections/AbstractMutableList.kt
@@ -22,6 +22,11 @@ public actual abstract class AbstractMutableList<E> protected actual constructor
     abstract override fun removeAt(index: Int): E
     abstract override fun set(index: Int, element: E): E
 
+    /**
+     * Adds the specified element to the end of this list.
+     *
+     * @return `true` because the list is always modified as the result of this operation.
+     */
     actual override fun add(element: E): Boolean {
         add(size, element)
         return true