diff --git a/core/lib/Drupal/Core/Render/AttachmentsResponseProcessorInterface.php b/core/lib/Drupal/Core/Render/AttachmentsResponseProcessorInterface.php
index d99cd7e..6067a86 100644
--- a/core/lib/Drupal/Core/Render/AttachmentsResponseProcessorInterface.php
+++ b/core/lib/Drupal/Core/Render/AttachmentsResponseProcessorInterface.php
@@ -49,6 +49,8 @@
    *   The processed response.
    *
    * @throws \InvalidArgumentException
+   *   Thrown when the $response parameter is not the type of response object
+   *   the processor expects.
    */
   public function processAttachments(AttachmentsInterface $response);