--- /dev/null
+<?php
+
+namespace Drupal\Core\Ajax;
+
+/**
+ * Interface for Ajax commands that render content and attach assets.
+ *
+ * All Ajax commands that render HTML should implement these methods
+ * to be able to return attached assets to the calling AjaxResponse object.
+ *
+ * @ingroup ajax
+ */
+interface CommandWithAttachedAssetsInterface {
+
+ /**
+ * Gets the attached assets.
+ *
+ * @return \Drupal\Core\Asset\AttachedAssets|null
+ * The attached assets for this command.
+ */
+ public function getAttachedAssets();
+
+}