diff --git a/src/Attributes/CallableAttr.php b/src/Attributes/CallableAttr.php
new file mode 100644
index 0000000..3686044
--- /dev/null
+++ b/src/Attributes/CallableAttr.php
@@ -0,0 +1,49 @@
+<?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\Parameter\Attributes;
+
+use Attribute;
+use Chevere\Parameter\Interfaces\ParameterAttributeInterface;
+use Chevere\Parameter\Interfaces\ParameterInterface;
+use LogicException;
+use function Chevere\Parameter\object;
+
+#[Attribute(Attribute::TARGET_METHOD | Attribute::TARGET_FUNCTION)]
+class CallableAttr implements ParameterAttributeInterface
+{
+    public readonly ParameterInterface $parameter;
+
+    public function __construct(callable $callable)
+    {
+        $return = $callable();
+        object(ParameterInterface::class)($return);
+        // if (!is_object($return)) {
+        //     throw new LogicException('DynamicAttr must return an object');
+        // }
+        // if (! $return instanceof ParameterInterface) {
+        //     throw new LogicException('DynamicAttr must return an object implementing ParameterInterface');
+        // }
+        $this->parameter = $return;
+    }
+
+    public function __invoke(mixed $mixed): mixed
+    {
+        return $this->parameter->__invoke($mixed);
+    }
+
+    public function parameter(): ParameterInterface
+    {
+        return $this->parameter;
+    }
+}
diff --git a/src/Attributes/NullAttr.php b/src/Attributes/NullAttr.php
new file mode 100644
index 0000000..d1ff4d8
--- /dev/null
+++ b/src/Attributes/NullAttr.php
@@ -0,0 +1,44 @@
+<?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\Parameter\Attributes;
+
+use Attribute;
+use Chevere\Parameter\Interfaces\NullParameterInterface;
+use Chevere\Parameter\Interfaces\ParameterAttributeInterface;
+use Chevere\Parameter\Interfaces\ParameterInterface;
+use function Chevere\Parameter\null;
+
+#[Attribute(Attribute::TARGET_PROPERTY | Attribute::TARGET_PARAMETER | Attribute::TARGET_CLASS_CONSTANT)]
+class NullAttr implements ParameterAttributeInterface
+{
+    public readonly NullParameterInterface $parameter;
+
+    public function __construct(
+        string $description = '',
+    ) {
+        $this->parameter = null(
+            description: $description,
+        );
+    }
+
+    public function __invoke(mixed $null): mixed
+    {
+        return $this->parameter->__invoke($null);
+    }
+
+    public function parameter(): ParameterInterface
+    {
+        return $this->parameter;
+    }
+}
diff --git a/src/Attributes/functions.php b/src/Attributes/functions.php
index 0d6e3ba..792ee73 100644
--- a/src/Attributes/functions.php
+++ b/src/Attributes/functions.php
@@ -18,6 +18,7 @@
 use ReflectionAttribute;
 use ReflectionFunction;
 use ReflectionMethod;
+use Throwable;
 use function Chevere\Parameter\parameterAttr;
 use function Chevere\Parameter\reflectionToParameters;
 
@@ -99,11 +100,14 @@ function arrayArguments(string $name): ArgumentsInterface
 }
 
 /**
- * Validates argument `$name` against attribute rules.
+ * Validates argument `$name` against parameter attribute rules.
+ *
+ * @param ?string $name Argument name or `null` to validate all arguments.
  */
-function validate(?string $name = null): void
+function valid(?string $name = null): void
 {
-    $caller = debug_backtrace(0, 2)[1];
+    $trace = debug_backtrace(0, 2);
+    $caller = $trace[1];
     $class = $caller['class'] ?? false;
     $method = $caller['function'];
     $args = $caller['args'] ?? [];
@@ -122,7 +126,18 @@ function validate(?string $name = null): void
 
         return;
     }
-    $parameters->get($name)->__invoke($arguments[$name]);
+
+    try {
+        $parameters->get($name)->__invoke($arguments[$name]);
+    } catch (Throwable $e) {
+        $invoker = $trace[0];
+        // @phpstan-ignore-next-line
+        $fileLine = $invoker['file'] . ':' . $invoker['line'];
+
+        throw new $e(
+            $e->getMessage() . ' >>> ' . $fileLine
+        );
+    }
 }
 
 /**
@@ -130,9 +145,10 @@ function validate(?string $name = null): void
  *
  * @return mixed The validated `$var`.
  */
-function returnAttr(mixed $var): mixed
+function validReturn(mixed $var): mixed
 {
-    $caller = debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS, 2)[1];
+    $trace = debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS, 2);
+    $caller = $trace[1];
     $class = $caller['class'] ?? null;
     $method = $caller['function'];
     $reflection = $class
@@ -142,5 +158,15 @@ function returnAttr(mixed $var): mixed
     $attribute = $reflection->getAttributes(ReturnAttr::class)[0]
         ?? throw new LogicException('No return attribute found');
 
-    return $attribute->newInstance()->__invoke($var);
+    try {
+        return $attribute->newInstance()->__invoke($var);
+    } catch (Throwable $e) {
+        $invoker = $trace[0];
+        // @phpstan-ignore-next-line
+        $fileLine = $invoker['file'] . ':' . $invoker['line'];
+
+        throw new $e(
+            $e->getMessage() . ' >>> ' . $fileLine
+        );
+    }
 }
diff --git a/tests/src/UsesParameterAttributes.php b/tests/src/UsesParameterAttributes.php
index 752bbd2..244c890 100644
--- a/tests/src/UsesParameterAttributes.php
+++ b/tests/src/UsesParameterAttributes.php
@@ -14,20 +14,26 @@
 namespace Chevere\Tests\src;
 
 use Chevere\Parameter\Attributes\ArrayAttr;
+use Chevere\Parameter\Attributes\CallableAttr;
 use Chevere\Parameter\Attributes\GenericAttr;
 use Chevere\Parameter\Attributes\IntAttr;
 use Chevere\Parameter\Attributes\ReturnAttr;
 use Chevere\Parameter\Attributes\StringAttr;
+use Chevere\Parameter\Interfaces\ParameterInterface;
 use function Chevere\Parameter\Attributes\arrayArguments;
 use function Chevere\Parameter\Attributes\arrayAttr;
 use function Chevere\Parameter\Attributes\genericAttr;
 use function Chevere\Parameter\Attributes\intAttr;
-use function Chevere\Parameter\Attributes\returnAttr;
 use function Chevere\Parameter\Attributes\stringAttr;
-use function Chevere\Parameter\Attributes\validate;
+use function Chevere\Parameter\Attributes\valid;
+use function Chevere\Parameter\Attributes\validReturn;
+use function Chevere\Parameter\int;
 
 final class UsesParameterAttributes
 {
+    #[ReturnAttr(
+        new CallableAttr(__CLASS__ . '::acceptResponse')
+    )]
     public function __construct(
         #[StringAttr('/^[A-Za-z]+$/')]
         string $name = 'Test',
@@ -42,16 +48,22 @@ public function __construct(
         )]
         iterable $tags = [],
     ) {
-        validate('name');
-        validate('age');
-        validate('cols');
-        validate('tags');
-        validate();
+        valid('name');
+        valid('age');
+        valid('cols');
+        valid('tags');
+        valid();
         $name = stringAttr('name')($name);
         $age = intAttr('age')($age);
         $cols = arrayAttr('cols')($cols);
         $id = arrayArguments('cols')->required('id')->int();
         $tags = genericAttr('tags')($tags);
+        validReturn($id);
+    }
+
+    public static function acceptResponse(): ParameterInterface
+    {
+        return int();
     }
 
     #[ReturnAttr(
@@ -59,6 +71,6 @@ public function __construct(
     )]
     public function run(int $int): int
     {
-        return returnAttr($int);
+        return validReturn($int);
     }
 }
diff --git a/tests/src/functions.php b/tests/src/functions.php
index 90861d6..99eaa45 100644
--- a/tests/src/functions.php
+++ b/tests/src/functions.php
@@ -19,7 +19,7 @@
 use Chevere\Parameter\Attributes\IntAttr;
 use Chevere\Parameter\Attributes\ReturnAttr;
 use Chevere\Parameter\Attributes\StringAttr;
-use function Chevere\Parameter\Attributes\validate;
+use function Chevere\Parameter\Attributes\valid;
 
 #[ReturnAttr(
     new BoolAttr()
@@ -37,7 +37,7 @@ function myArray(
     )]
     array $spooky
 ): bool {
-    validate('spooky');
+    valid('spooky');
 
     return true;
 }