diff -u b/src/Event/ParagraphSummaryAlterEvent.php b/src/Event/ParagraphSummaryAlterEvent.php
--- b/src/Event/ParagraphSummaryAlterEvent.php
+++ b/src/Event/ParagraphSummaryAlterEvent.php
@@ -50,2 +50,9 @@
 
+  /**
+   * Set new summary.
+   */
+  public function setSummary(array $text_array) {
+    $this->summary['content'] = $text_array;
+  }
+
 }