diff --git a/src/Attributes/Description.php b/src/Attributes/Description.php
new file mode 100644
index 0000000..e3496db
--- /dev/null
+++ b/src/Attributes/Description.php
@@ -0,0 +1,31 @@
+<?php
+
+/*
+ * This file is part of Chevere.
+ *
+ * (c) Rodolfo Berrios <rodolfo@chevere.org>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace Chevere\Http\Attributes;
+
+use Attribute;
+use Stringable;
+
+#[Attribute]
+class Description implements Stringable
+{
+    public function __construct(
+        public readonly string $description = '',
+    ) {
+    }
+
+    public function __toString(): string
+    {
+        return $this->description;
+    }
+}
diff --git a/src/Controller.php b/src/Controller.php
index a77f1b6..9cf1791 100644
--- a/src/Controller.php
+++ b/src/Controller.php
@@ -18,6 +18,9 @@
 use Chevere\Parameter\Interfaces\ArgumentsInterface;
 use Chevere\Parameter\Interfaces\ArrayParameterInterface;
 use Chevere\Parameter\Interfaces\ArrayStringParameterInterface;
+use LogicException;
+use Throwable;
+use function Chevere\Message\message;
 use function Chevere\Parameter\arguments;
 use function Chevere\Parameter\arrayp;
 use function Chevere\Parameter\arrayString;
@@ -29,9 +32,9 @@ abstract class Controller extends BaseController implements ControllerInterface
     private ?ArgumentsInterface $body = null;
 
     /**
-     * @var array<ArgumentsInterface>
+     * @var ?array<ArgumentsInterface>
      */
-    private array $files = [];
+    private ?array $files = null;
 
     public static function acceptQuery(): ArrayStringParameterInterface
     {
@@ -98,13 +101,24 @@ final public function body(): ArgumentsInterface
 
     final public function files(): array
     {
-        return $this->files;
+        return $this->files
+            ??= [];
     }
 
     protected function assertRuntime(): void
     {
-        $this->query();
-        $this->body();
-        $this->files();
+        foreach (['query', 'body', 'files'] as $method) {
+            try {
+                $this->{$method}();
+            } catch (Throwable $e) {
+                throw new LogicException(
+                    (string) message(
+                        '%topic%: %message%',
+                        topic: $method,
+                        message: $e->getMessage()
+                    )
+                );
+            }
+        }
     }
 }
diff --git a/src/functions.php b/src/functions.php
index 4beb5c3..f8dfbaa 100644
--- a/src/functions.php
+++ b/src/functions.php
@@ -13,10 +13,16 @@
 
 namespace Chevere\Http;
 
+use Chevere\Http\Attributes\Description;
 use Chevere\Http\Attributes\Request;
 use Chevere\Http\Attributes\Response;
 use Chevere\Http\Interfaces\MiddlewaresInterface;
 use ReflectionClass;
+use ReflectionClassConstant;
+use ReflectionFunction;
+use ReflectionMethod;
+use ReflectionParameter;
+use ReflectionProperty;
 
 function middlewares(string ...$middleware): MiddlewaresInterface
 {
@@ -32,21 +38,37 @@ function requestAttribute(string $className): Request
 {
     // @phpstan-ignore-next-line
     $reflection = new ReflectionClass($className);
-    $attributes = $reflection->getAttributes(Request::class);
-    if ($attributes === []) {
-        return new (Request::class)();
-    }
 
-    return $attributes[0]->newInstance();
+    // @phpstan-ignore-next-line
+    return getAttribute($reflection, Request::class);
 }
 
 function responseAttribute(string $className): Response
 {
     // @phpstan-ignore-next-line
     $reflection = new ReflectionClass($className);
-    $attributes = $reflection->getAttributes(Response::class);
+
+    // @phpstan-ignore-next-line
+    return getAttribute($reflection, Response::class);
+}
+
+function descriptionAttribute(string $className): Description
+{
+    // @phpstan-ignore-next-line
+    $reflection = new ReflectionClass($className);
+
+    // @phpstan-ignore-next-line
+    return getAttribute($reflection, Description::class);
+}
+
+// @phpstan-ignore-next-line
+function getAttribute(
+    ReflectionClass|ReflectionFunction|ReflectionMethod|ReflectionProperty|ReflectionParameter|ReflectionClassConstant $reflection,
+    string $attribute
+): object {
+    $attributes = $reflection->getAttributes($attribute);
     if ($attributes === []) {
-        return new (Response::class)();
+        return new $attribute();
     }
 
     return $attributes[0]->newInstance();
diff --git a/tests/ControllerTest.php b/tests/ControllerTest.php
index 9087f34..87cbc67 100644
--- a/tests/ControllerTest.php
+++ b/tests/ControllerTest.php
@@ -18,10 +18,20 @@
 use Chevere\Tests\src\AcceptOptionalController;
 use Chevere\Tests\src\NullController;
 use InvalidArgumentException;
+use LogicException;
+use OutOfBoundsException;
 use PHPUnit\Framework\TestCase;
 
 final class ControllerTest extends TestCase
 {
+    public function testAssertRuntime(): void
+    {
+        $controller = new AcceptController();
+        $this->expectException(LogicException::class);
+        $this->expectExceptionMessage('query: Missing required argument(s): `foo`');
+        $controller->getResponse();
+    }
+
     public function testDefaults(): void
     {
         $controller = new NullController();
@@ -86,27 +96,53 @@ public function testAcceptBodyParametersOptional(): void
         $this->assertSame('123', $controllerWith->body()->optional('bar')->string());
     }
 
-    public function testAcceptFileParameters(): void
+    public function testAcceptFile(): void
     {
         $controller = new AcceptController();
-        $file = [
+        $myFile = [
             'error' => UPLOAD_ERR_OK,
             'name' => 'readme.txt',
-            'size' => 1313,
+            'size' => 12345,
             'type' => 'text/plain',
             'tmp_name' => '/tmp/file.yx5kVl',
         ];
+        $myImage = [
+            'error' => UPLOAD_ERR_OK,
+            'name' => 'image.png',
+            'size' => 1234,
+            'type' => 'image/png',
+            'tmp_name' => '/tmp/file.pnp4t1',
+        ];
         $this->assertSame([], $controller->files());
         $controllerWith = $controller->withFiles([
-            'MyFile' => $file,
+            'myFile' => $myFile,
+            'myImage' => $myImage,
         ]);
         $this->assertNotSame($controller, $controllerWith);
         $this->assertNotEquals($controller, $controllerWith);
-        $myFile = $controllerWith->files()['MyFile'];
-        $this->assertSame($file, $myFile->toArray());
+        $theFile = $controllerWith->files()['myFile'];
+        $theImage = $controllerWith->files()['myImage'];
+        $this->assertSame($myFile, $theFile->toArray());
+        $this->assertSame($myImage, $theImage->toArray());
+    }
+
+    public function testAcceptFileInvalidArgument(): void
+    {
+        $controller = new AcceptController();
         $this->expectException(ArgumentCountError::class);
+        $this->expectExceptionMessage('Missing required argument(s): `error, name, size, type, tmp_name`');
+        $controller->withFiles([
+            'myFile' => [],
+        ]);
+    }
+
+    public function testAcceptFileMissingKey(): void
+    {
+        $controller = new AcceptController();
+        $this->expectException(OutOfBoundsException::class);
+        $this->expectExceptionMessage('Missing key(s) `404`');
         $controller->withFiles([
-            'MyFile' => [],
+            '404' => [],
         ]);
     }
 }
diff --git a/tests/src/AcceptController.php b/tests/src/AcceptController.php
index 34a861f..48e8c80 100644
--- a/tests/src/AcceptController.php
+++ b/tests/src/AcceptController.php
@@ -52,11 +52,16 @@ public static function acceptBody(): ArrayParameterInterface
 
     public static function acceptFiles(): ArrayParameterInterface
     {
-        return arrayp(
-            MyFile: file(
-                type: string('/^text\/plain$/')
-            )
-        );
+        return
+            arrayp(
+                myFile: file(
+                    type: string('/^text\/plain$/')
+                )
+            )->withOptional(
+                myImage: file(
+                    type: string('/^image\/png$/')
+                )
+            );
     }
 
     public function run(): array
diff --git a/tests/src/AcceptOptionalController.php b/tests/src/AcceptOptionalController.php
index d781f7d..0fc1789 100644
--- a/tests/src/AcceptOptionalController.php
+++ b/tests/src/AcceptOptionalController.php
@@ -48,7 +48,7 @@ public static function acceptBody(): ArrayParameterInterface
     public static function acceptFiles(): ArrayParameterInterface
     {
         return arrayp()->withOptional(
-            MyFile: file(
+            myFile: file(
                 type: string('/^text\/plain$/')
             )
         );