diff --git a/src/Builder/InterfaceBuilder.php b/src/Builder/InterfaceBuilder.php
index 822e7e3..b3ccd24 100644
--- a/src/Builder/InterfaceBuilder.php
+++ b/src/Builder/InterfaceBuilder.php
@@ -4,20 +4,20 @@
 
 namespace SimPod\GraphQLUtils\Builder;
 
+use GraphQL\Type\Definition\AbstractType;
 use GraphQL\Type\Definition\FieldDefinition;
 use GraphQL\Type\Definition\InterfaceType;
 
 /**
- * @see               InterfaceType
- *
  * @phpstan-import-type InterfaceConfig from InterfaceType
+ * @phpstan-import-type ResolveType from AbstractType
  */
 class InterfaceBuilder extends TypeBuilder
 {
     /** @var InterfaceType[] */
     private array $interfaces = [];
 
-    /** @var callable|null */
+    /** @var ResolveType|null */
     private $resolveType;
 
     /** @var array<FieldDefinition|array<string, mixed>>|callable():array<FieldDefinition|array<string, mixed>> */
@@ -53,7 +53,11 @@ public function setFields(callable|array $fields): self
         return $this;
     }
 
-    /** @return $this */
+    /**
+     * @param ResolveType $resolveType
+     *
+     * @return $this
+     */
     public function setResolveType(callable $resolveType): self
     {
         $this->resolveType = $resolveType;
diff --git a/tests/Builder/InterfaceBuilderTest.php b/tests/Builder/InterfaceBuilderTest.php
index c9f479d..72783a7 100644
--- a/tests/Builder/InterfaceBuilderTest.php
+++ b/tests/Builder/InterfaceBuilderTest.php
@@ -39,7 +39,7 @@ public function __construct()
                 ],
             )
             ->setResolveType(
-                static fn (bool $value): Type => $value ? Type::string() : Type::int(),
+                static fn (mixed $value) => $value === true ? 'type' : null,
             )
             ->build();
 
@@ -55,8 +55,8 @@ public function __construct()
         self::assertCount(1, $interface['fields']);
         self::assertArrayHasKey('resolveType', $interface);
         self::assertIsCallable($interface['resolveType']);
-        self::assertSame(Type::string(), $interface['resolveType'](true, null, $resolveInfo));
-        self::assertSame(Type::int(), $interface['resolveType'](false, null, $resolveInfo));
+        self::assertSame('type', $interface['resolveType'](true, null, $resolveInfo));
+        self::assertNull($interface['resolveType'](false, null, $resolveInfo));
     }
 
     public function testInvalidValue(): void