diff --git a/src/Potter/Container/ContainerInterface.php b/src/Potter/Container/ContainerInterface.php
new file mode 100644
index 0000000..ac1dbad
--- /dev/null
+++ b/src/Potter/Container/ContainerInterface.php
@@ -0,0 +1,13 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Potter\Container;
+
+use \Psr\Container\ContainerInterface as BaseContainerInterface;
+
+interface ContainerInterface extends BaseContainerInterface
+{
+    public function get(string $key): mixed;
+    public function has(string $key): bool;
+}