diff --git a/libraries/exoplayer/src/main/java/androidx/media3/exoplayer/source/ShuffleOrder.java b/libraries/exoplayer/src/main/java/androidx/media3/exoplayer/source/ShuffleOrder.java
index 6d75f13b53..e6e2e1b2dc 100644
--- a/libraries/exoplayer/src/main/java/androidx/media3/exoplayer/source/ShuffleOrder.java
+++ b/libraries/exoplayer/src/main/java/androidx/media3/exoplayer/source/ShuffleOrder.java
@@ -24,6 +24,9 @@ import java.util.Random;
  * Shuffled order of indices.
  *
  * <p>The shuffle order must be immutable to ensure thread safety.
+ *
+ * <p>The order must be consistent when traversed both {@linkplain #getNextIndex(int) forwards} and
+ * {@linkplain #getPreviousIndex(int) backwards}.
  */
 @UnstableApi
 public interface ShuffleOrder {