diff --git a/src/wp-includes/ms-functions.php b/src/wp-includes/ms-functions.php
index bcdf5bcefc..04fba60faa 100644
--- a/src/wp-includes/ms-functions.php
+++ b/src/wp-includes/ms-functions.php
@@ -2162,7 +2162,12 @@ function maybe_add_existing_user_to_blog() {
  *
  * @since MU (3.0.0)
  *
- * @param array $details User details.
+ * @param array $details {
+ *     User details. Must at least contain values for the keys listed below.
+ *
+ *     @type int    $user_id The ID of the user being added to the current blog.
+ *     @type string $role    The role to be assigned to the user.
+ * }
  * @return true|WP_Error|void True on success or a WP_Error object if the user doesn't exist
  *                            or could not be added. Void if $details array was not provided.
  */