diff --git a/src/Config/Filters.php b/src/Config/Filters.php
index 5d7cc3d1..772e45bb 100644
--- a/src/Config/Filters.php
+++ b/src/Config/Filters.php
@@ -160,9 +160,11 @@ private function handleTags(string|int|TaggedValue $value): array
         $operator = '=';
 
         if ($value instanceof TaggedValue) {
-            if ($value->getTag() === 'NOT') {
-                $operator = '!=';
-            }
+            match ($value->getTag()) {
+                'NOT' => $operator = '!=',
+                'IN' => $operator = 'contains',
+                default => $operator,
+            };
             $value = (string) $value->getValue();
         }
 
diff --git a/src/Preparator/Config/Error400BadFormatsPreparatorConfig.php b/src/Preparator/Config/Error400BadFormatsPreparatorConfig.php
deleted file mode 100644
index 18e17d0d..00000000
--- a/src/Preparator/Config/Error400BadFormatsPreparatorConfig.php
+++ /dev/null
@@ -1,9 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-namespace APITester\Preparator\Config;
-
-final class Error400BadFormatsPreparatorConfig extends Error400PreparatorConfig
-{
-}
diff --git a/src/Preparator/Config/Error400BadTypesPreparatorConfig.php b/src/Preparator/Config/Error400BadTypesPreparatorConfig.php
deleted file mode 100644
index 0342fc6e..00000000
--- a/src/Preparator/Config/Error400BadTypesPreparatorConfig.php
+++ /dev/null
@@ -1,9 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-namespace APITester\Preparator\Config;
-
-final class Error400BadTypesPreparatorConfig extends Error400PreparatorConfig
-{
-}
diff --git a/src/Preparator/Config/Error400MissingRequiredFieldsPreparatorConfig.php b/src/Preparator/Config/Error400MissingRequiredFieldsPreparatorConfig.php
deleted file mode 100644
index f2f2b155..00000000
--- a/src/Preparator/Config/Error400MissingRequiredFieldsPreparatorConfig.php
+++ /dev/null
@@ -1,9 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-namespace APITester\Preparator\Config;
-
-final class Error400MissingRequiredFieldsPreparatorConfig extends Error400PreparatorConfig
-{
-}
diff --git a/src/Preparator/Config/Error400PreparatorConfig.php b/src/Preparator/Config/Error400PreparatorConfig.php
deleted file mode 100644
index 09b81ca0..00000000
--- a/src/Preparator/Config/Error400PreparatorConfig.php
+++ /dev/null
@@ -1,10 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-namespace APITester\Preparator\Config;
-
-abstract class Error400PreparatorConfig extends PreparatorConfig
-{
-    public bool $excludeOpenApiEndpoints = false;
-}
diff --git a/src/Preparator/Error400Preparator.php b/src/Preparator/Error400Preparator.php
index 1dac5be3..03b54d92 100644
--- a/src/Preparator/Error400Preparator.php
+++ b/src/Preparator/Error400Preparator.php
@@ -12,12 +12,8 @@
 use APITester\Definition\Example\ResponseExample;
 use APITester\Definition\Operation;
 use APITester\Definition\Parameter;
-use APITester\Preparator\Config\Error400PreparatorConfig;
 use APITester\Test\TestCase;
 
-/**
- * @property Error400PreparatorConfig $config
- */
 abstract class Error400Preparator extends TestCasesPreparator
 {
     /**
@@ -122,10 +118,6 @@ protected function getStatusCode(): string
      */
     private function prepareTestCases(Operation $operation): array
     {
-        if ($this->config->excludeOpenApiEndpoints
-            && isset($operation->getExtensions()['x-usecase'])) {
-            return [];
-        }
         $requiredParams = $operation->getParameters(true);
 
         return array_merge(
diff --git a/src/Util/Traits/FilterableTrait.php b/src/Util/Traits/FilterableTrait.php
index 6e229c47..7ef8b7c0 100644
--- a/src/Util/Traits/FilterableTrait.php
+++ b/src/Util/Traits/FilterableTrait.php
@@ -9,6 +9,7 @@ trait FilterableTrait
     public function has(string $prop, $value, string $operator = '='): bool
     {
         $self = collect([$this]);
+
         if (str_contains($prop, '*')) {
             $operator = 'contains';
         }
diff --git a/tests/Preparator/Error400MissingRequiredFieldsPreparatorTest.php b/tests/Preparator/Error400MissingRequiredFieldsPreparatorTest.php
index b762e1f8..a74d2b5c 100644
--- a/tests/Preparator/Error400MissingRequiredFieldsPreparatorTest.php
+++ b/tests/Preparator/Error400MissingRequiredFieldsPreparatorTest.php
@@ -22,7 +22,7 @@ final class Error400MissingRequiredFieldsPreparatorTest extends \PHPUnit\Framewo
      * @dataProvider getData
      *
      * @param array<string, array<mixed>> $config
-     * @param TestCase[] $expected
+     * @param TestCase[]                  $expected
      */
     public function test(Api $api, array $expected, array $config = []): void
     {
@@ -165,48 +165,5 @@ public function getData(): iterable
                 ),
             ],
         ];
-
-        yield 'openapi endpoint is ignored' => [
-            Api::create()
-                ->addOperation(
-                    Operation::create(
-                        'test',
-                        '/test',
-                        'POST'
-                    )
-                        ->addRequestBody(
-                            (new Body(
-                                new Schema([
-                                    'type' => 'object',
-                                    'properties' => [
-                                        'foo' => [
-                                            'type' => 'string',
-                                        ],
-                                        'bar' => [
-                                            'type' => 'string',
-                                        ],
-                                    ],
-                                    'required' => ['foo'],
-                                ]),
-                                'application/json'
-                            ))
-                        )
-                        ->addExample(
-                            OperationExample::create('foo')
-                                ->setBodyContent([
-                                    'foo' => 'foo_body1',
-                                    'bar' => 'bar_body1',
-                                ])
-                                ->setQueryParameter('foo_query', 'foo1')
-                        )->setExtensions([
-                            'x-usecase' => 'UseCaseName',
-                        ])
-                ),
-            [
-            ],
-            [
-                'excludeOpenApiEndpoints' => true,
-            ],
-        ];
     }
 }