diff --git a/src/CommandBus.php b/src/CommandBus.php
index 4425938..19bc059 100644
--- a/src/CommandBus.php
+++ b/src/CommandBus.php
@@ -19,6 +19,12 @@ public function __construct(
     ) {
     }
 
+    /**
+     * @throws CommandNotRegisteredException
+     * @throws \Throwable
+     *
+     * @psalm-suppress InvalidReturnType
+     */
     public function dispatch(CommandInterface $command): mixed
     {
         try {
diff --git a/src/Exception/CommandNotRegisteredException.php b/src/Exception/CommandNotRegisteredException.php
index 2195dfa..b1dfac8 100644
--- a/src/Exception/CommandNotRegisteredException.php
+++ b/src/Exception/CommandNotRegisteredException.php
@@ -12,7 +12,7 @@ public function __construct(CommandInterface $command, \Throwable $previous)
     {
         parent::__construct(
             sprintf("The command <%s> hasn't a command handler associated", get_class($command)),
-            $previous->getCode(),
+            (int)$previous->getCode(),
             $previous
         );
     }
diff --git a/src/Exception/HandlerTypeIsNotSupported.php b/src/Exception/HandlerTypeIsNotSupported.php
index 2d76929..069a090 100644
--- a/src/Exception/HandlerTypeIsNotSupported.php
+++ b/src/Exception/HandlerTypeIsNotSupported.php
@@ -8,7 +8,7 @@
 
 class HandlerTypeIsNotSupported extends CqrsException
 {
-    public function __construct(Envelope $envelope, ?Throwable $previous = null)
+    public function __construct(Envelope $envelope, ?\Throwable $previous = null)
     {
         parent::__construct(
             \sprintf(
diff --git a/src/Exception/QueryNotRegisteredException.php b/src/Exception/QueryNotRegisteredException.php
index afe11e9..cc552d4 100644
--- a/src/Exception/QueryNotRegisteredException.php
+++ b/src/Exception/QueryNotRegisteredException.php
@@ -12,7 +12,7 @@ public function __construct(QueryInterface $query, \Throwable $previous = null)
     {
         parent::__construct(
             sprintf("The query <%s> hasn't a query handler associated", get_class($query)),
-            $previous->getCode(),
+            (int)$previous->getCode(),
             $previous
         );
     }
diff --git a/src/HandlersLocator.php b/src/HandlersLocator.php
index d375bdf..1eb7268 100644
--- a/src/HandlersLocator.php
+++ b/src/HandlersLocator.php
@@ -4,6 +4,10 @@
 
 namespace Spiral\Cqrs;
 
+use Generator;
+use ReflectionMethod;
+use ReflectionNamedType;
+use ReflectionType;
 use Spiral\Attributes\ReaderInterface;
 use Spiral\Core\Container;
 use Spiral\Cqrs\Attribute\CommandHandler;
@@ -84,11 +88,12 @@ private function shouldHandle(Envelope $envelope, HandlerDescriptor $handlerDesc
             return true;
         }
 
+        /** @var ReceivedStamp $received */
         return $received->getTransportName() === $expectedTransport;
     }
 
     /**
-     * @param array{0: class-string, 1: non-empty-string}  $handler
+     * @param array{0: class-string, 1: non-empty-string} $handler
      */
     private function buildHandlerDescriptor(array $handler): HandlerDescriptor
     {
@@ -113,13 +118,13 @@ private function lookForHandlers()
         }
     }
 
-    private function processCommandHandler(\ReflectionMethod $method): void
+    private function processCommandHandler(ReflectionMethod $method): void
     {
         $this->assertHandlerMethodIsPublic($method);
 
-        foreach ($method->getParameters() as $parameter) {
-            if (is_a($parameter->getType()->getName(), CommandInterface::class, true)) {
-                $this->commandHandlers[$parameter->getType()->getName()][] = [
+        foreach ($this->getMethodParameters($method) as $parameter) {
+            if (is_a($parameter->getName(), CommandInterface::class, true)) {
+                $this->commandHandlers[$parameter->getName()][] = [
                     $method->getDeclaringClass()->getName(),
                     $method->getName(),
                 ];
@@ -127,13 +132,13 @@ private function processCommandHandler(\ReflectionMethod $method): void
         }
     }
 
-    private function processQueryHandler(\ReflectionMethod $method)
+    private function processQueryHandler(ReflectionMethod $method)
     {
         $this->assertHandlerMethodIsPublic($method);
 
-        foreach ($method->getParameters() as $parameter) {
-            if (is_a($parameter->getType()->getName(), QueryInterface::class, true)) {
-                $this->queryHandlers[$parameter->getType()->getName()][] = [
+        foreach ($this->getMethodParameters($method) as $parameter) {
+            if (is_a($parameter->getName(), QueryInterface::class, true)) {
+                $this->queryHandlers[$parameter->getName()][] = [
                     $method->getDeclaringClass()->getName(),
                     $method->getName(),
                 ];
@@ -144,7 +149,7 @@ private function processQueryHandler(\ReflectionMethod $method)
     /**
      * @throws InvalidHandlerException
      */
-    private function assertHandlerMethodIsPublic(\ReflectionMethod $method): void
+    private function assertHandlerMethodIsPublic(ReflectionMethod $method): void
     {
         if (! $method->isPublic()) {
             throw new InvalidHandlerException(
@@ -156,4 +161,21 @@ private function assertHandlerMethodIsPublic(\ReflectionMethod $method): void
             );
         }
     }
+
+    /**
+     * @param ReflectionMethod $method
+     * @return Generator<int, ReflectionNamedType|ReflectionType|null>
+     */
+    private function getMethodParameters(ReflectionMethod $method): Generator
+    {
+        foreach ($method->getParameters() as $parameter) {
+            if ($parameter->getType() instanceof \ReflectionUnionType) {
+                foreach ($parameter->getType()->getTypes() as $type) {
+                    yield $type;
+                }
+            } else {
+                yield $parameter->getType();
+            }
+        }
+    }
 }
diff --git a/src/MessageBusExceptionTrait.php b/src/MessageBusExceptionTrait.php
index 82c0853..63df233 100644
--- a/src/MessageBusExceptionTrait.php
+++ b/src/MessageBusExceptionTrait.php
@@ -8,6 +8,9 @@
 
 trait MessageBusExceptionTrait
 {
+    /**
+     * @throws \Throwable
+     */
     public function throwException(HandlerFailedException $exception): void
     {
         while ($exception instanceof HandlerFailedException) {
diff --git a/src/QueryBus.php b/src/QueryBus.php
index 328db65..9ad9455 100644
--- a/src/QueryBus.php
+++ b/src/QueryBus.php
@@ -19,6 +19,12 @@ public function __construct(
     ) {
     }
 
+    /**
+     * @throws QueryNotRegisteredException
+     * @throws \Throwable
+     *
+     * @psalm-suppress InvalidReturnType
+     */
     public function ask(QueryInterface $query): mixed
     {
         try {
diff --git a/tests/app/Command/UpdateUser.php b/tests/app/Command/UpdateUser.php
new file mode 100644
index 0000000..bb9b4ea
--- /dev/null
+++ b/tests/app/Command/UpdateUser.php
@@ -0,0 +1,16 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Spiral\Cqrs\Tests\App\Command;
+
+use Spiral\Cqrs\CommandInterface;
+
+class UpdateUser implements CommandInterface
+{
+    public function __construct(
+        public string $username,
+        public string $password
+    ) {
+    }
+}
diff --git a/tests/app/Handler/StoreUserHandler.php b/tests/app/Handler/StoreUserHandler.php
index fa2d8b7..0c1adb1 100644
--- a/tests/app/Handler/StoreUserHandler.php
+++ b/tests/app/Handler/StoreUserHandler.php
@@ -5,6 +5,7 @@
 namespace Spiral\Cqrs\Tests\App\Handler;
 
 use Spiral\Cqrs\Tests\App\Command\StoreUser;
+use Spiral\Cqrs\Tests\App\Command\UpdateUser;
 use Spiral\Cqrs\Tests\App\EntityManagerInterface;
 
 final class StoreUserHandler
@@ -16,7 +17,7 @@ public function __construct(
     }
 
     #[\Spiral\Cqrs\Attribute\CommandHandler]
-    public function __invoke(StoreUser $command)
+    public function __invoke(StoreUser|UpdateUser $command)
     {
         $this->entityManager->store([
             'uuid' => $command->uuid,