diff --git a/config/params.php b/config/params.php
index 8f805018..549a0e92 100644
--- a/config/params.php
+++ b/config/params.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 use Yiisoft\Di\Command\DebugContainerCommand;
 
 return [
diff --git a/src/Command/DebugContainerCommand.php b/src/Command/DebugContainerCommand.php
index 1427ea7b..86828035 100644
--- a/src/Command/DebugContainerCommand.php
+++ b/src/Command/DebugContainerCommand.php
@@ -188,4 +188,3 @@ protected function export(mixed $value): string
         return VarDumper::create($value)->asString();
     }
 }
-
diff --git a/tests/Unit/Command/DebugContainerCommandTest.php b/tests/Unit/Command/DebugContainerCommandTest.php
index 5ecd6ea5..bcad82ce 100644
--- a/tests/Unit/Command/DebugContainerCommandTest.php
+++ b/tests/Unit/Command/DebugContainerCommandTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 namespace Yiisoft\Di\Tests\Unit\Command;
 
 use PHPUnit\Framework\TestCase;
@@ -46,4 +48,3 @@ private function createContainer(): ContainerInterface
         return new Container($config);
     }
 }
-