diff --git a/library/Icinga/Application/Hook/PdfexportHook.php b/library/Icinga/Application/Hook/PdfexportHook.php
index 36e9f515c1..defa0f0fe5 100644
--- a/library/Icinga/Application/Hook/PdfexportHook.php
+++ b/library/Icinga/Application/Hook/PdfexportHook.php
@@ -3,6 +3,8 @@
 
 namespace Icinga\Application\Hook;
 
+use Icinga\Module\Pdfexport\PrintableHtmlDocument;
+
 /**
  * Base class for the PDF Export Hook
  */
@@ -18,8 +20,8 @@ abstract public function isSupported();
     /**
      * Render the specified HTML to PDF and stream it to the client
      *
-     * @param   string  $html       The HTML to render to PDF
-     * @param   string  $filename   The filename for the generated PDF
+     * @param   string|PrintableHtmlDocument    $html       The HTML to render to PDF
+     * @param   string                          $filename   The filename for the generated PDF
      */
-    abstract public function streamPdfFromHtml($html, $filename);
+    abstract public function streamPdfFromHtml($html, string $filename);
 }