diff --git a/src/Integrations/Divi/Design/DiviPresetsSetAbility.php b/src/Integrations/Divi/Design/DiviPresetsSetAbility.php
index b84b034..cb8026f 100644
--- a/src/Integrations/Divi/Design/DiviPresetsSetAbility.php
+++ b/src/Integrations/Divi/Design/DiviPresetsSetAbility.php
@@ -236,6 +236,17 @@ final class DiviPresetsSetAbility implements Ability
             return null;
         }
 
+        if ($existing === null && isset($item['rename'])) {
+            $errors[$field . '.rename'] = 'nur zusammen mit preset; für ein neues Preset name verwenden';
+
+            return null;
+        }
+        if ($existing !== null && isset($item['name'])) {
+            $errors[$field . '.name'] = 'zum Umbenennen rename verwenden';
+
+            return null;
+        }
+
         foreach (['name' => $existing === null, 'rename' => $existing !== null] as $key => $applies) {
             if (! $applies || ! is_string($item[$key] ?? null)) {
                 continue;
@@ -269,10 +280,12 @@ final class DiviPresetsSetAbility implements Ability
     /** Plain text of 1 to 100 characters, or null (ruling: preset names). */
     private function cleanName(string $name): ?string
     {
+        if (strlen($name) > self::NAME_MAX * 4) {
+            return null;
+        }
         $clean = sanitize_text_field($name);
-        $length = function_exists('mb_strlen') ? mb_strlen($clean) : strlen($clean);
 
-        return $clean === '' || $length > self::NAME_MAX || strlen($name) > self::NAME_MAX * 4 ? null : $clean;
+        return $clean === '' || mb_strlen($clean) > self::NAME_MAX ? null : $clean;
     }
 
     /**
diff --git a/tests/Unit/Integrations/Divi/Design/DiviPresetsSetAbilityTest.php b/tests/Unit/Integrations/Divi/Design/DiviPresetsSetAbilityTest.php
index d78fa57..a0b6e0c 100644
--- a/tests/Unit/Integrations/Divi/Design/DiviPresetsSetAbilityTest.php
+++ b/tests/Unit/Integrations/Divi/Design/DiviPresetsSetAbilityTest.php
@@ -192,6 +192,29 @@ final class DiviPresetsSetAbilityTest extends TestCase
         self::assertStringContainsString('1–100 Zeichen', $empty['fields']['items[0].rename']);
     }
 
+    public function testNameAndRenameAreExclusive(): void
+    {
+        $ability = $this->ability();
+        $new = self::assertToolError($ability->execute(['items' => [
+            ['module' => 'button', 'name' => 'Neu', 'rename' => '<b>x</b>'],
+        ]]), 'validation_failed');
+        self::assertStringContainsString('nur zusammen mit preset', $new['fields']['items[0].rename']);
+
+        $change = self::assertToolError($ability->execute(['items' => [
+            ['module' => 'button', 'preset' => 'CTA primär', 'name' => 'CTA primär'],
+        ]]), 'validation_failed');
+        self::assertStringContainsString('rename', $change['fields']['items[0].name']);
+    }
+
+    public function testRenameToAnotherPresetsNameIsRefused(): void
+    {
+        $result = self::assertToolError($this->ability()->execute(['items' => [
+            ['module' => 'button', 'preset' => 'CTA primär', 'rename' => 'Doppelt'],
+        ]]), 'validation_failed');
+
+        self::assertStringContainsString('bbbbbbbbbb', $result['fields']['items[0].rename']);
+    }
+
     public function testNothingIsWrittenWhenOneItemHasErrors(): void
     {
         $writer = Mockery::mock(DesignSystemWriter::class);
@@ -202,7 +225,8 @@ final class DiviPresetsSetAbilityTest extends TestCase
         $ability = $this->ability(true, null, null, $writer);
 
         $result = $ability->execute(['items' => [
-            ['module' => 'button', 'name' => 'Gut'],
+            ['module' => 'button', 'name' => 'Gut',
+                'attrs' => ['button.decoration.background' => ['desktop' => ['color' => '#333333']]]],
             ['module' => 'button', 'name' => 'Schlecht', 'attrs' => ['button.innerContent' => ['desktop' => ['text' => 'Hallo']]]],
         ], 'confirm' => true, 'design_rev' => 'egal']);