diff --git a/psalm.xml b/psalm.xml
index 90d05be..151f7b6 100644
--- a/psalm.xml
+++ b/psalm.xml
@@ -15,4 +15,7 @@
             <directory name="vendor" />
         </ignoreFiles>
     </projectFiles>
+    <issueHandlers>
+        <UndefinedAttributeClass errorLevel="suppress" />
+    </issueHandlers>
 </psalm>
diff --git a/src/Builder.php b/src/Builder.php
index d67705e..9f6a12a 100644
--- a/src/Builder.php
+++ b/src/Builder.php
@@ -22,6 +22,7 @@ private function __construct(array $definitions)
     /**
      * @psalm-pure
      */
+    #[\NoDiscard]
     public static function new(): self
     {
         return new self([]);
@@ -31,6 +32,7 @@ public static function new(): self
      * @param string|Service $name Using a string is deprecated
      * @param callable(Container): object $definition
      */
+    #[\NoDiscard]
     public function add(string|Service $name, callable $definition): self
     {
         if ($name instanceof Service) {
@@ -43,6 +45,7 @@ public function add(string|Service $name, callable $definition): self
         return new self($definitions);
     }
 
+    #[\NoDiscard]
     public function build(): Container
     {
         return Container::of($this->definitions);