diff --git a/src/Browser/KernelBrowser.php b/src/Browser/KernelBrowser.php
index 52bb607..8d11565 100644
--- a/src/Browser/KernelBrowser.php
+++ b/src/Browser/KernelBrowser.php
@@ -469,7 +469,9 @@ final public function assertHeaderContains(string $header, string $expected): se
     {
         Assert::that($this->client()->getResponse()->headers->get($header))
             ->isNotNull('Header "{header}" is not present in the response.', ['header' => $header])
-            ->contains($expected, 'Header "{header}" is "{actual}", but "{expected}" expected.', ['header' => $header])
+            ->contains($expected, 'Header "{header}" value "{haystack}" is expected to contain "{needle}".', [
+                'header' => $header,
+            ])
         ;
 
         return $this;