diff --git a/src/Attributes/Bootstrap.php b/src/Attributes/Bootstrap.php
index 725151c8f6..d5b4b4daf9 100644
--- a/src/Attributes/Bootstrap.php
+++ b/src/Attributes/Bootstrap.php
@@ -15,7 +15,7 @@ class Bootstrap
      *   The level to bootstrap to.
      */
     public function __construct(
-        #[ExpectedValues(valuesFromClass: DrupalBootLevels::class)] public string $level,
+        #[ExpectedValues(valuesFromClass: DrupalBootLevels::class)] public int $level,
     ) {
     }