diff --git a/src/Attribute/Reader/Reader.php b/src/Attribute/Reader/Reader.php
index b8f3ac6..af25212 100644
--- a/src/Attribute/Reader/Reader.php
+++ b/src/Attribute/Reader/Reader.php
@@ -57,22 +57,6 @@ public function getAttribute(ReflectionClass|ReflectionProperty|ReflectionMethod
     {
         $attributes = $this->getAttributeInstances($element, $attributeName);
 
-        return $this->onlyOne($attributes);
-    }
-
-    /**
-     * @template T of ApiAttribute
-     *
-     * @param T[] $attributes
-     *
-     * @return null|T
-     */
-    private function onlyOne(array $attributes): ?ApiAttribute
-    {
-        if (count($attributes) > 1) {
-            throw new Exception('Expected to find single attribute, but found many');
-        }
-
         return reset($attributes) ?: null;
     }
 
@@ -86,7 +70,7 @@ private function onlyOne(array $attributes): ?ApiAttribute
     private function getAttributeInstances(ReflectionClass|ReflectionMethod|ReflectionParameter|ReflectionProperty $element, string $attributeName): array
     {
         if (!is_subclass_of($attributeName, ApiAttribute::class)) {
-            throw new Exception('This should not be used for attribute than are not ours');
+            throw new Exception(self::class . ' cannot be used for attribute than are not part of `ecodev/graphql-doctrine`.');
         }
 
         $attributes = $element->getAttributes($attributeName);
diff --git a/tests/Attribute/Reader/ReaderTest.php b/tests/Attribute/Reader/ReaderTest.php
index e41ed84..f0701ce 100644
--- a/tests/Attribute/Reader/ReaderTest.php
+++ b/tests/Attribute/Reader/ReaderTest.php
@@ -5,6 +5,7 @@
 namespace GraphQLTests\Doctrine\Attribute\Reader;
 
 use GraphQL\Doctrine\Attribute\Argument;
+use GraphQL\Doctrine\Attribute\Exclude;
 use GraphQL\Doctrine\Attribute\Field;
 use GraphQL\Doctrine\Attribute\Filter;
 use GraphQL\Doctrine\Attribute\FilterGroupCondition;
@@ -17,6 +18,7 @@
 use ReflectionClass;
 use ReflectionMethod;
 use ReflectionProperty;
+use ReturnTypeWillChange;
 
 class ReaderTest extends TestCase
 {
@@ -80,4 +82,37 @@ public function testGetParameterAttribute(): void
             $this->reader->getAttribute((new ReflectionMethod(User::class, 'getPosts'))->getParameters()[0], Argument::class)
         );
     }
+
+    public function testWillThrowIfUniqueAttributeIsUsedMultipleTimes(): void
+    {
+        $mock = new class() {
+            #[Exclude]
+            /** @phpstan-ignore-next-line */
+            #[Exclude]
+            /**
+             * @phpstan-ignore-next-line
+             */
+            private $foo;
+        };
+
+        $this->expectExceptionMessage('Attribute "GraphQL\Doctrine\Attribute\Exclude" must not be repeated');
+        $this->reader->getAttribute(new ReflectionProperty($mock, 'foo'), Exclude::class);
+    }
+
+    public function testWillThrowIfReaderIsUsedWithOtherAttributes(): void
+    {
+        $mock = new class() {
+            /**
+             * @phpstan-ignore-next-line
+             */
+            #[ReturnTypeWillChange]
+            private function foo(): void
+            {
+            }
+        };
+
+        $this->expectExceptionMessage('GraphQL\Doctrine\Attribute\Reader\Reader cannot be used for attribute than are not part of `ecodev/graphql-doctrine`.');
+        // @phpstan-ignore-next-line
+        $this->reader->getAttribute(new ReflectionMethod($mock, 'foo'), ReturnTypeWillChange::class);
+    }
 }
diff --git a/tests/Blog/Model/Special/ArgumentOverrideDefaultValue.php b/tests/Blog/Model/Special/ArgumentOverrideDefaultValue.php
new file mode 100644
index 0000000..5ec41a5
--- /dev/null
+++ b/tests/Blog/Model/Special/ArgumentOverrideDefaultValue.php
@@ -0,0 +1,18 @@
+<?php
+
+declare(strict_types=1);
+
+namespace GraphQLTests\Doctrine\Blog\Model\Special;
+
+use Doctrine\ORM\Mapping as ORM;
+use GraphQL\Doctrine\Attribute\Argument;
+use GraphQLTests\Doctrine\Blog\Model\AbstractModel;
+
+#[ORM\Entity]
+final class ArgumentOverrideDefaultValue extends AbstractModel
+{
+    public function getWithParams(#[Argument(defaultValue: 2)] int $param = 1): string
+    {
+        return __FUNCTION__;
+    }
+}
diff --git a/tests/OutputTypesTest.php b/tests/OutputTypesTest.php
index d291442..63c8902 100644
--- a/tests/OutputTypesTest.php
+++ b/tests/OutputTypesTest.php
@@ -101,4 +101,10 @@ public function testFieldWithObjectTypeArgumentMustThrow(): void
         $type = $this->types->getOutput(Blog\Model\Special\ObjectTypeArgument::class);
         $type->getFields();
     }
+
+    public function testCanOverrideArgumentDefaultValue(): void
+    {
+        $actual = $this->types->getOutput(Blog\Model\Special\ArgumentOverrideDefaultValue::class);
+        $this->assertType('tests/data/ArgumentOverrideDefaultValue.graphqls', $actual);
+    }
 }
diff --git a/tests/data/ArgumentOverrideDefaultValue.graphqls b/tests/data/ArgumentOverrideDefaultValue.graphqls
new file mode 100644
index 0000000..0b0c255
--- /dev/null
+++ b/tests/data/ArgumentOverrideDefaultValue.graphqls
@@ -0,0 +1,5 @@
+type ArgumentOverrideDefaultValue {
+  withParams(param: Int = 2): String!
+  id: ID!
+  creationDate: DateTime!
+}