diff --git a/src/Options/CliOption.php b/src/Options/CliOption.php
index cf6ac4f..c462015 100644
--- a/src/Options/CliOption.php
+++ b/src/Options/CliOption.php
@@ -10,8 +10,8 @@ use RuntimeException;
 final class CliOption
 {
     private function __construct(
-        public Action $action,
-        public string $file
+        public readonly Action $action,
+        public readonly string $file
     ) {
     }