diff --git a/src/Integrations/Divi/Design/DesignRights.php b/src/Integrations/Divi/Design/DesignRights.php
new file mode 100644
index 0000000..038475b
--- /dev/null
+++ b/src/Integrations/Divi/Design/DesignRights.php
@@ -0,0 +1,34 @@
+<?php
+
+declare(strict_types=1);
+
+namespace LIT\MCP\Integrations\Divi\Design;
+
+use LIT\MCP\Abilities\Errors;
+use WP_Error;
+
+defined('ABSPATH') || exit;
+
+/**
+ * Who may change the design system (spec §10): presets need edit_theme_options and Divi's role right "Visual Builder
+ * verwenden" – what Divi's own preset sync asks since 5.15 (formats "Nachtrag 5.15.1").
+ */
+final class DesignRights
+{
+    public static function presets(DesignSystemWriter $writer): ?WP_Error
+    {
+        if (! current_user_can('edit_theme_options')) {
+            return Errors::forbidden(
+                'Presets ändern erfordert das Recht, das Design der Website anzupassen (edit_theme_options).'
+            );
+        }
+        if (! $writer->canUseVisualBuilder()) {
+            return Errors::forbidden(
+                'Die Divi-Rolle dieses Kontos erlaubt den Visual Builder nicht; ohne ihn ändert LIT MCP keine Presets.',
+                'Einen Administrator bitten, das Recht unter Divi → Rollen-Editor freizugeben.'
+            );
+        }
+
+        return null;
+    }
+}
diff --git a/src/Integrations/Divi/Design/DiviPresetsSetAbility.php b/src/Integrations/Divi/Design/DiviPresetsSetAbility.php
new file mode 100644
index 0000000..b84b034
--- /dev/null
+++ b/src/Integrations/Divi/Design/DiviPresetsSetAbility.php
@@ -0,0 +1,319 @@
+<?php
+
+declare(strict_types=1);
+
+namespace LIT\MCP\Integrations\Divi\Design;
+
+use Closure;
+use InvalidArgumentException;
+use LIT\MCP\Abilities\Ability;
+use LIT\MCP\Abilities\Annotations;
+use LIT\MCP\Abilities\Errors;
+use LIT\MCP\Integrations\Divi\BlockTree\Block;
+use LIT\MCP\Integrations\Divi\Library\GlobalUsages;
+use LIT\MCP\Integrations\Divi\Pages\DiviPageLoader;
+use WP_Error;
+
+defined('ABSPATH') || exit;
+
+/**
+ * lit/divi-presets-set (spec §6.3, G7): creates and changes module and option group presets – from the short and full
+ * form, from a module of a page (from_node), with nested group presets and as the default preset – through the
+ * change pipeline (dry run, design_rev, snapshot, Divi's sync, change log). New names must be free within the
+ * module/group (A5). The dry run lists the posts that use a changed preset or reach a new default.
+ */
+final class DiviPresetsSetAbility implements Ability
+{
+    public const MAX_ITEMS = 20;
+
+    private const NAME_MAX = 100;
+
+    private const NAME_RULE = 'Name: 1–100 Zeichen, ohne HTML';
+
+    private const GROUP_DEFAULT_WARNING = 'Standard-Gruppen-Presets wirken zusätzlich auf alle Module mit dieser '
+        . 'Gruppe ohne eigenes Gruppen-Preset; diese Seiten sind nicht aufgelistet.';
+
+    /** @param Closure(): PresetComposer $composer */
+    public function __construct(
+        private DesignSystemWriter $writer,
+        private DesignChange $change,
+        private GlobalUsages $usages,
+        private DiviPageLoader $loader,
+        private Closure $composer
+    ) {
+    }
+
+    public function name(): string
+    {
+        return 'lit/divi-presets-set';
+    }
+
+    public function label(): string
+    {
+        return 'Divi-Presets anlegen und ändern';
+    }
+
+    public function description(): string
+    {
+        return 'Legt Modul-Presets (module) und Gruppen-Presets (group) an oder ändert sie (preset = Name oder ID). '
+            . 'Einstellungen in attrs (Vollform wie bei lit-divi-update, mit Platzhaltern {{color:…}}/{{var:…}}) oder '
+            . 'aus einem Modul einer Seite (from_node: post_id + Pfad-ID); nur Gestaltung, keine Texte oder Links. '
+            . 'group_presets verschachtelt Gruppen-Presets, make_default macht das Preset zum Standard. Wirkt auf alle '
+            . 'Seiten: zuerst Probelauf (diff, betroffene Seiten, design_rev), nach Rückfrage beim '
+            . 'Nutzer confirm: true mit design_rev. Vorher wird ein Snapshot angelegt (lit/divi-design-restore).';
+    }
+
+    public function inputSchema(): array
+    {
+        return [
+            'type' => 'object',
+            'properties' => [
+                'items' => [
+                    'type' => 'array',
+                    'minItems' => 1,
+                    'maxItems' => self::MAX_ITEMS,
+                    'items' => [
+                        'type' => 'object',
+                        'properties' => [
+                            'module' => ['type' => 'string'],
+                            'group' => ['type' => 'string'],
+                            'preset' => ['type' => 'string', 'description' => 'Zu änderndes Preset (Name oder ID).'],
+                            'name' => ['type' => 'string', 'description' => 'Name eines neuen Presets.'],
+                            'rename' => ['type' => 'string'],
+                            'set' => ['type' => 'object'],
+                            'attrs' => ['type' => 'object'],
+                            'from_node' => [
+                                'type' => 'object',
+                                'properties' => ['post_id' => ['type' => 'integer'], 'id' => ['type' => 'string']],
+                                'required' => ['post_id', 'id'],
+                            ],
+                            'source_module' => ['type' => 'string', 'description' => 'Neues Gruppen-Preset: Modul.'],
+                            'group_id' => ['type' => 'string'],
+                            'group_presets' => ['type' => 'object'],
+                            'make_default' => ['type' => 'boolean'],
+                        ],
+                    ],
+                ],
+            ] + DesignChange::inputProperties(),
+            'required' => ['items'],
+            'additionalProperties' => false,
+        ];
+    }
+
+    public function outputSchema(): ?array
+    {
+        return DesignChange::outputSchema();
+    }
+
+    public function annotations(): array
+    {
+        return Annotations::destructive(false);
+    }
+
+    public function isDirect(): bool
+    {
+        return false;
+    }
+
+    public function permission(array $input): bool|WP_Error
+    {
+        return DesignRights::presets($this->writer) ?? true;
+    }
+
+    public function execute(array $input): mixed
+    {
+        $refusal = DesignRights::presets($this->writer);
+        if ($refusal !== null) {
+            return $refusal;
+        }
+        $items = $input['items'] ?? null;
+        if (! is_array($items) || ! array_is_list($items) || $items === [] || count($items) > self::MAX_ITEMS) {
+            return Errors::invalidInput(
+                'items fehlt oder ist zu lang; nichts wurde gespeichert.',
+                ['items' => sprintf('1 bis %d Einträge', self::MAX_ITEMS)]
+            );
+        }
+
+        return $this->change->run(
+            $this->name(),
+            new PresetArea($this->writer),
+            $input,
+            fn (array $raw): DesignPlan|WP_Error => $this->plan(PresetBook::fromDivi($raw), $items)
+        );
+    }
+
+    /** @param list<mixed> $items */
+    private function plan(PresetBook $before, array $items): DesignPlan|WP_Error
+    {
+        $composer = ($this->composer)();
+        $book = $before;
+        $errors = [];
+        $invalid = [];
+        $targets = [];
+        $warnings = [];
+        foreach ($items as $index => $item) {
+            $field = sprintf('items[%d]', $index);
+            if (! is_array($item)) {
+                $errors[$field] = 'Objekt erwartet';
+                continue;
+            }
+            $prepared = $this->prepare($book, $item, $field, $errors);
+            if ($prepared === null) {
+                continue;
+            }
+            [$scope, $existing, $source] = $prepared;
+            $result = $composer->compose($book, $scope, $existing, $item, $field, $source);
+            $invalid = array_merge($invalid, $result['invalid_paths']);
+            if ($result['errors'] !== [] || $result['invalid_paths'] !== []) {
+                $errors += $result['errors'];
+                continue;
+            }
+            $id = (string) $result['item']['id'];
+            $book = $book->with($scope, $result['item']);
+            if (($item['make_default'] ?? null) === true) {
+                $book = $book->withDefault($scope, $id);
+                if ($scope->kind === PresetScope::GROUP) {
+                    $warnings[] = self::GROUP_DEFAULT_WARNING;
+                }
+            } elseif (($item['make_default'] ?? null) === false && $book->defaultId($scope) === $id) {
+                $book = $book->withDefault($scope, '');
+            }
+            if ($existing !== null || $book->defaultId($scope) === $id) {
+                $targets[] = ['scope' => $scope, 'id' => $id, 'default' => $before->defaultId($scope) === $id
+                    || $book->defaultId($scope) === $id];
+            }
+        }
+
+        if ($invalid !== []) {
+            return Errors::invalidAttrPath($errors);
+        }
+        if ($errors !== []) {
+            return Errors::invalidInput('Ungültige Preset-Angaben; nichts wurde gespeichert.', $errors);
+        }
+
+        $diff = PresetDiff::between($before, $book);
+
+        return new DesignPlan(
+            $book->data(),
+            $diff,
+            PresetDiff::summary($diff),
+            $targets === [] ? null : $this->usages->reportFor(new PresetUsageQuery($targets)),
+            array_values(array_unique($warnings))
+        );
+    }
+
+    /**
+     * Scope, preset to change and source node of one item; null after noting the problem in $errors.
+     *
+     * @param array<array-key, mixed> $item   Names are replaced by their cleaned form.
+     * @param array<string, string>   $errors
+     * @return array{PresetScope, array<string, mixed>|null, Block|null}|null
+     */
+    private function prepare(PresetBook $book, array &$item, string $field, array &$errors): ?array
+    {
+        try {
+            $scope = PresetScope::fromInput($item, $field);
+        } catch (InvalidArgumentException $e) {
+            [$path, $problem] = explode(': ', $e->getMessage(), 2) + [1 => ''];
+            $errors[$path] = $problem;
+
+            return null;
+        }
+
+        $existing = null;
+        try {
+            if (is_string($item['preset'] ?? null)) {
+                $existing = $book->find($scope, $item['preset']);
+                if ($existing === null) {
+                    $errors[$field . '.preset'] = sprintf('unbekanntes %s „%s“', $scope->label(), $item['preset']);
+
+                    return null;
+                }
+            }
+        } catch (InvalidArgumentException $e) {
+            $errors[$field . '.preset'] = $e->getMessage();
+
+            return null;
+        }
+
+        foreach (['name' => $existing === null, 'rename' => $existing !== null] as $key => $applies) {
+            if (! $applies || ! is_string($item[$key] ?? null)) {
+                continue;
+            }
+            $name = $this->cleanName($item[$key]);
+            if ($name === null) {
+                $errors[$field . '.' . $key] = self::NAME_RULE;
+
+                return null;
+            }
+            $item[$key] = $name;
+            $taken = array_diff($book->idsNamed($scope, $name), [(string) ($existing['id'] ?? '')]);
+            if ($taken !== []) {
+                $errors[$field . '.' . $key] = sprintf(
+                    'Name schon vergeben (%s); zum Ändern preset angeben oder einen anderen Namen wählen',
+                    implode(', ', $taken)
+                );
+
+                return null;
+            }
+        }
+
+        $source = $this->source($scope, $item, $field, $errors);
+        if ($source === false) {
+            return null;
+        }
+
+        return [$scope, $existing, $source];
+    }
+
+    /** Plain text of 1 to 100 characters, or null (ruling: preset names). */
+    private function cleanName(string $name): ?string
+    {
+        $clean = sanitize_text_field($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;
+    }
+
+    /**
+     * @param array<array-key, mixed> $item
+     * @param array<string, string>   $errors
+     */
+    private function source(PresetScope $scope, array $item, string $field, array &$errors): Block|false|null
+    {
+        $from = $item['from_node'] ?? null;
+        if ($from === null) {
+            return null;
+        }
+        if (! is_array($from) || ! is_string($from['id'] ?? null)) {
+            $errors[$field . '.from_node'] = 'post_id und id (Pfad-ID aus lit-divi-outline) erwartet';
+
+            return false;
+        }
+
+        $page = $this->loader->load($from['post_id'] ?? null, false);
+        if ($page instanceof WP_Error) {
+            $errors[$field . '.from_node.post_id'] = Errors::clientMessage($page);
+
+            return false;
+        }
+        $block = $page->index->find($from['id']);
+        if ($block === null) {
+            $errors[$field . '.from_node.id'] = sprintf('unbekannte Pfad-ID %s (lit-divi-outline)', $from['id']);
+
+            return false;
+        }
+        if ($scope->kind === PresetScope::MODULE && $block->name() !== $scope->name) {
+            $errors[$field . '.from_node.id'] = sprintf(
+                '%s ist %s, nicht %s',
+                $from['id'],
+                $block->name(),
+                $scope->name
+            );
+
+            return false;
+        }
+
+        return $block;
+    }
+}
diff --git a/src/Integrations/Divi/Design/PresetDiff.php b/src/Integrations/Divi/Design/PresetDiff.php
index e10ab9f..de94d77 100644
--- a/src/Integrations/Divi/Design/PresetDiff.php
+++ b/src/Integrations/Divi/Design/PresetDiff.php
@@ -39,6 +39,30 @@ final class PresetDiff
         return $rows;
     }
 
+    /**
+     * One German sentence for the dry run and the change log (spec §4 step 6).
+     *
+     * @param list<array<string, mixed>> $diff
+     */
+    public static function summary(array $diff): string
+    {
+        $count = array_count_values(array_map(static fn (array $row): string => (string) $row['action'], $diff));
+        $parts = array_filter([
+            isset($count['added']) ? $count['added'] . ' angelegt' : null,
+            isset($count['changed']) ? $count['changed'] . ' geändert' : null,
+            isset($count['removed']) ? $count['removed'] . ' gelöscht' : null,
+        ]);
+        $defaults = array_filter([
+            isset($count['default_set']) ? $count['default_set'] . '× gesetzt' : null,
+            isset($count['default_cleared']) ? $count['default_cleared'] . '× entfernt' : null,
+        ]);
+        if ($defaults !== []) {
+            $parts[] = 'Standard ' . implode(', ', $defaults);
+        }
+
+        return 'Presets: ' . ($parts === [] ? 'keine Änderung' : implode(', ', $parts)) . '.';
+    }
+
     /**
      * @param array<string, array<string, mixed>> $was
      * @param array<string, array<string, mixed>> $is
diff --git a/src/Integrations/Divi/DiviIntegration.php b/src/Integrations/Divi/DiviIntegration.php
index d1c8546..e0fb791 100644
--- a/src/Integrations/Divi/DiviIntegration.php
+++ b/src/Integrations/Divi/DiviIntegration.php
@@ -10,7 +10,11 @@ use LIT\MCP\Integrations\Divi\BlockTree\Parser;
 use LIT\MCP\Integrations\Divi\Design\DesignSystemReader;
 use LIT\MCP\Integrations\Divi\Design\DesignSystemWriter;
 use LIT\MCP\Integrations\Divi\Design\DiviDesignSystemAbility;
+use LIT\MCP\Integrations\Divi\Design\DesignChange;
 use LIT\MCP\Integrations\Divi\Design\DiviPresetGetAbility;
+use LIT\MCP\Integrations\Divi\Design\DiviPresetsSetAbility;
+use LIT\MCP\Integrations\Divi\Design\PresetComposer;
+use LIT\MCP\Integrations\Divi\Design\SnapshotStore;
 use LIT\MCP\Integrations\Divi\Library\DiviLibraryStore;
 use LIT\MCP\Integrations\Divi\Library\DiviRoles;
 use LIT\MCP\Integrations\Divi\Library\GlobalEdits;
@@ -155,6 +159,13 @@ final class DiviIntegration implements Integration
             new DiviNodeCopyAbility($writer, $loader, $this->diviWritable, $this->libraryInsertable),
             new DiviDynamicSourcesAbility($this->schema, new DynamicContentMap(), $this->access->roles()),
             new DiviPresetGetAbility($this->designWriter, $this->globalUsages()),
+            new DiviPresetsSetAbility(
+                $this->designWriter,
+                $this->designChange(),
+                $this->globalUsages(),
+                $loader,
+                $this->presetComposer(...)
+            ),
         ];
     }
 
@@ -217,6 +228,25 @@ final class DiviIntegration implements Integration
         );
     }
 
+    private function designChange(): DesignChange
+    {
+        return new DesignChange(new SnapshotStore(), $this->log);
+    }
+
+    private function presetComposer(): PresetComposer
+    {
+        $composition = new DiviComposition($this->modules, $this->design);
+
+        return new PresetComposer(
+            $composition->composer(),
+            $composition->storedGuard(),
+            $this->designWriter->presetAttrs(...),
+            $this->designWriter->groupsOf(...),
+            $this->modules->builderVersion(),
+            static fn (): int => (int) floor(microtime(true) * 1000)
+        );
+    }
+
     private function loader(): DiviPageLoader
     {
         return new DiviPageLoader($this->schema, new Parser(), $this->access, $this->themeBuilderAccess);
diff --git a/tests/Unit/Integrations/Divi/Design/DesignRightsTest.php b/tests/Unit/Integrations/Divi/Design/DesignRightsTest.php
new file mode 100644
index 0000000..4867ef6
--- /dev/null
+++ b/tests/Unit/Integrations/Divi/Design/DesignRightsTest.php
@@ -0,0 +1,29 @@
+<?php
+
+declare(strict_types=1);
+
+namespace LIT\MCP\Tests\Unit\Integrations\Divi\Design;
+
+use Brain\Monkey\Functions;
+use LIT\MCP\Integrations\Divi\Design\DesignRights;
+use LIT\MCP\Integrations\Divi\Design\DesignSystemWriter;
+use LIT\MCP\Tests\Unit\TestCase;
+use Mockery;
+
+final class DesignRightsTest extends TestCase
+{
+    public function testPresetsNeedEditThemeOptionsAndTheVisualBuilder(): void
+    {
+        $writer = Mockery::mock(DesignSystemWriter::class);
+        $writer->allows('canUseVisualBuilder')->andReturn(true, false);
+        Functions\when('current_user_can')->alias(static fn (string $cap): bool => $cap === 'edit_theme_options');
+
+        self::assertNull(DesignRights::presets($writer));
+        $refusal = self::assertToolError(DesignRights::presets($writer), 'forbidden');
+        self::assertStringContainsString('Visual Builder', $refusal['message']);
+
+        Functions\when('current_user_can')->justReturn(false);
+        $refusal = self::assertToolError(DesignRights::presets($writer), 'forbidden');
+        self::assertStringContainsString('edit_theme_options', $refusal['message']);
+    }
+}
diff --git a/tests/Unit/Integrations/Divi/Design/DiviPresetsSetAbilityTest.php b/tests/Unit/Integrations/Divi/Design/DiviPresetsSetAbilityTest.php
new file mode 100644
index 0000000..d78fa57
--- /dev/null
+++ b/tests/Unit/Integrations/Divi/Design/DiviPresetsSetAbilityTest.php
@@ -0,0 +1,232 @@
+<?php
+
+declare(strict_types=1);
+
+namespace LIT\MCP\Tests\Unit\Integrations\Divi\Design;
+
+use Brain\Monkey\Functions;
+use LIT\MCP\Abilities\Errors;
+use LIT\MCP\Integrations\Divi\Compose\StoredNodeGuard;
+use LIT\MCP\Integrations\Divi\Design\DesignChange;
+use LIT\MCP\Integrations\Divi\Design\DesignSystemWriter;
+use LIT\MCP\Integrations\Divi\Design\DiviPresetsSetAbility;
+use LIT\MCP\Integrations\Divi\Design\PresetBook;
+use LIT\MCP\Integrations\Divi\Design\PresetComposer;
+use LIT\MCP\Integrations\Divi\Design\PresetScope;
+use LIT\MCP\Integrations\Divi\Design\SnapshotStore;
+use LIT\MCP\Integrations\Divi\Library\GlobalUsages;
+use LIT\MCP\Integrations\Divi\Library\UsageReport;
+use LIT\MCP\Integrations\Divi\Pages\DiviPageLoader;
+use LIT\MCP\Tests\Support\ComposeFixture;
+use LIT\MCP\Tests\Support\DiviFixtures;
+use LIT\MCP\Tests\Support\FakeChangeLog;
+use LIT\MCP\Tests\Unit\TestCase;
+use Mockery;
+
+final class DiviPresetsSetAbilityTest extends TestCase
+{
+    /** @var array<string, mixed> */
+    private array $stored;
+
+    private SnapshotStore $snapshots;
+
+    protected function setUp(): void
+    {
+        parent::setUp();
+        $this->stored = PresetBookTest::stored();
+        $this->snapshots = Mockery::mock(SnapshotStore::class);
+        Functions\when('current_user_can')->justReturn(true);
+    }
+
+    private function ability(bool $unfiltered = true, ?GlobalUsages $usages = null, ?DiviPageLoader $loader = null, ?DesignSystemWriter $writer = null): DiviPresetsSetAbility
+    {
+        $writer ??= $this->savingWriter();
+        $usages ??= Mockery::mock(GlobalUsages::class);
+        $usages->allows('reportFor')->andReturn(new UsageReport(0, [], 0, 0, [], 0, false));
+        return $this->build($writer, $usages, $loader, $unfiltered);
+    }
+
+    private function savingWriter(): DesignSystemWriter
+    {
+        $writer = Mockery::mock(DesignSystemWriter::class);
+        $writer->allows('presets')->andReturnUsing(fn (): array => $this->stored);
+        $writer->allows('canUseVisualBuilder')->andReturn(true);
+        $writer->allows('savePresets')->andReturnUsing(function (array $rest, bool $mayRemove): array {
+            $data = ['module' => [], 'group' => []];
+            foreach ($rest as $kind => $records) {
+                foreach ($records as $record) {
+                    $first = $record['items'][0] ?? null;
+                    $name = $kind === 'group' ? ($first['groupName'] ?? 'x') : ($first['moduleName'] ?? 'x');
+                    $data[$kind][$name] = ['default' => $record['default'], 'items' => array_column($record['items'], null, 'id')];
+                }
+            }
+
+            return $this->stored = $data;
+        });
+
+        return $writer;
+    }
+
+    private function build(DesignSystemWriter $writer, GlobalUsages $usages, ?DiviPageLoader $loader, bool $unfiltered): DiviPresetsSetAbility
+    {
+        $composer = static fn (): PresetComposer => new PresetComposer(
+            ComposeFixture::composer($unfiltered),
+            new StoredNodeGuard(ComposeFixture::cleaner($unfiltered), ComposeFixture::references(),
+                ComposeFixture::sanitizer($unfiltered)),
+            static fn (string $module, array $attrs): array => ['all' => array_map(
+                static fn (mixed $v): mixed => is_array($v) ? array_diff_key($v, ['innerContent' => 1]) : $v,
+                $attrs
+            ), 'style' => [], 'render' => []],
+            static fn (string $module): array => ['module.decoration.spacing' => 'divi/spacing'],
+            '5.15.1',
+            static fn (): int => 1
+        );
+
+        return new DiviPresetsSetAbility(
+            $writer,
+            new DesignChange($this->snapshots, new FakeChangeLog(5)),
+            $usages,
+            $loader ?? new DiviPageLoader(DiviFixtures::schema()),
+            $composer
+        );
+    }
+
+    private static function newButton(array $extra = []): array
+    {
+        return ['items' => [$extra + ['module' => 'button', 'name' => 'CTA dunkel',
+            'attrs' => ['button.decoration.background' => ['desktop' => ['color' => '#111111']]]]]];
+    }
+
+    public function testDryRunThenConfirmCreatesThePreset(): void
+    {
+        $ability = $this->ability();
+
+        $dry = self::assertToolError($ability->execute(self::newButton()), 'confirm_required');
+        self::assertSame('added', $dry['diff'][0]['action']);
+        self::assertStringContainsString('Presets: 1 angelegt.', $dry['message']);
+
+        $this->snapshots->expects('save')->andReturn('presets-1');
+        $this->snapshots->expects('attachLog');
+        $result = $ability->execute(self::newButton() + ['confirm' => true, 'design_rev' => $dry['design_rev']]);
+
+        self::assertTrue($result['ok']);
+        self::assertSame('presets-1', $result['snapshot_id']);
+        $names = array_column(PresetBook::fromDivi($this->stored)->items(new PresetScope('module', 'divi/button')), 'name');
+        self::assertContains('CTA dunkel', $names);
+    }
+
+    public function testExistingNameIsRefusedForANewPreset(): void
+    {
+        $result = self::assertToolError($this->ability()->execute(['items' => [
+            ['module' => 'button', 'name' => 'CTA primär'],
+        ]]), 'validation_failed');
+
+        self::assertStringContainsString('aaaaaaaaaa', $result['fields']['items[0].name']);
+    }
+
+    public function testChangingAndMakingDefault(): void
+    {
+        $dry = self::assertToolError($this->ability()->execute(['items' => [[
+            'module' => 'button', 'preset' => 'CTA primär', 'make_default' => true,
+            'attrs' => ['button.decoration.background' => ['desktop' => ['color' => '#222222']]],
+        ]]]), 'confirm_required');
+
+        self::assertSame(['changed', 'default_set'], array_column($dry['diff'], 'action'));
+    }
+
+    public function testUnknownPresetAndBadItemsAreCollected(): void
+    {
+        $result = self::assertToolError($this->ability()->execute(['items' => [
+            ['module' => 'button', 'preset' => 'Fehlt'],
+            ['name' => 'ohne Modul'],
+        ]]), 'validation_failed');
+
+        self::assertArrayHasKey('items[0].preset', $result['fields']);
+        self::assertArrayHasKey('items[1]', $result['fields']);
+    }
+
+    public function testEditorWithoutUnfilteredHtmlIsRefusedForRawCss(): void
+    {
+        $result = $this->ability(false)->execute(['items' => [[
+            'module' => 'button', 'name' => 'Mit CSS',
+            'attrs' => ['css' => ['desktop' => ['mainElement' => 'color:red']]],
+        ]]]);
+
+        self::assertNotTrue(is_array($result) && ($result['ok'] ?? false));
+        self::assertContains(Errors::codeOf($result), ['validation_failed', 'invalid_attr_path']);
+    }
+
+    public function testFromNodeReadsThePage(): void
+    {
+        $content = '<!-- wp:divi/section --><!-- wp:divi/row --><!-- wp:divi/column -->'
+            . '<!-- wp:divi/button {"button":{"decoration":{"background":{"desktop":{"value":{"color":"#abcdef"}}}}}} /-->'
+            . '<!-- /wp:divi/column --><!-- /wp:divi/row --><!-- /wp:divi/section -->';
+        DiviFixtures::givenPost($content);
+        $loader = new DiviPageLoader(DiviFixtures::schema());
+
+        $dry = self::assertToolError($this->ability(true, null, $loader)->execute(['items' => [[
+            'module' => 'button', 'name' => 'Aus Seite', 'from_node' => ['post_id' => 7, 'id' => 's0.r0.c0.m0'],
+        ]]]), 'confirm_required');
+
+        self::assertSame('added', $dry['diff'][0]['action']);
+    }
+
+    public function testNamesAreCleanedAndLimited(): void
+    {
+        $ability = $this->ability();
+        $dry = self::assertToolError($ability->execute(self::newButton(['name' => '<b>Fett</b> Name'])), 'confirm_required');
+
+        $this->snapshots->expects('save')->andReturn('presets-1');
+        $this->snapshots->expects('attachLog');
+        $res = $ability->execute(self::newButton(['name' => '<b>Fett</b> Name']) + ['confirm' => true, 'design_rev' => $dry['design_rev']]);
+        self::assertTrue($res['ok']);
+        $names = array_column(PresetBook::fromDivi($this->stored)->items(new PresetScope('module', 'divi/button')), 'name');
+        self::assertContains('Fett Name', $names);
+        self::assertNotContains('<b>Fett</b> Name', $names);
+
+        $long = self::assertToolError($this->ability()->execute(self::newButton(['name' => str_repeat('n', 101)])), 'validation_failed');
+        self::assertStringContainsString('1–100 Zeichen', $long['fields']['items[0].name']);
+        $empty = self::assertToolError($this->ability()->execute(['items' => [
+            ['module' => 'button', 'preset' => 'CTA primär', 'rename' => '<i></i>'],
+        ]]), 'validation_failed');
+        self::assertStringContainsString('1–100 Zeichen', $empty['fields']['items[0].rename']);
+    }
+
+    public function testNothingIsWrittenWhenOneItemHasErrors(): void
+    {
+        $writer = Mockery::mock(DesignSystemWriter::class);
+        $writer->allows('presets')->andReturnUsing(fn (): array => $this->stored);
+        $writer->allows('canUseVisualBuilder')->andReturn(true);
+        $writer->shouldNotReceive('savePresets');
+        $this->snapshots->shouldNotReceive('save');
+        $ability = $this->ability(true, null, null, $writer);
+
+        $result = $ability->execute(['items' => [
+            ['module' => 'button', 'name' => 'Gut'],
+            ['module' => 'button', 'name' => 'Schlecht', 'attrs' => ['button.innerContent' => ['desktop' => ['text' => 'Hallo']]]],
+        ], 'confirm' => true, 'design_rev' => 'egal']);
+
+        self::assertContains(Errors::codeOf($result), ['validation_failed', 'invalid_attr_path']);
+        self::assertNotEmpty(array_filter(
+            array_keys(Errors::fieldsOf($result)),
+            static fn (string $key): bool => str_starts_with($key, 'items[1]')
+        ));
+    }
+
+    public function testNeedsEditThemeOptionsAndTheVisualBuilder(): void
+    {
+        Functions\when('current_user_can')->justReturn(false);
+
+        self::assertToolError($this->ability()->permission(self::newButton()), 'forbidden');
+    }
+
+    public function testSchemaAndMeta(): void
+    {
+        $ability = $this->ability();
+
+        self::assertSame('lit/divi-presets-set', $ability->name());
+        self::assertFalse($ability->isDirect());
+        self::assertSame(DiviPresetsSetAbility::MAX_ITEMS, $ability->inputSchema()['properties']['items']['maxItems']);
+        self::assertSame(['diff', 'design_rev'], array_slice($ability->outputSchema()['required'], -2));
+    }
+}
diff --git a/tests/Unit/Integrations/Divi/Design/PresetDiffTest.php b/tests/Unit/Integrations/Divi/Design/PresetDiffTest.php
index c01d4b9..7b6f003 100644
--- a/tests/Unit/Integrations/Divi/Design/PresetDiffTest.php
+++ b/tests/Unit/Integrations/Divi/Design/PresetDiffTest.php
@@ -46,4 +46,17 @@ final class PresetDiffTest extends TestCase
                 'action' => 'default_cleared'],
         ], PresetDiff::between($before, $after));
     }
+
+    public function testSummaryCountsTheActions(): void
+    {
+        self::assertSame(
+            'Presets: 1 angelegt, 1 geändert, 1 gelöscht, Standard 1× gesetzt, 1× entfernt.',
+            PresetDiff::summary([
+                ['action' => 'added'], ['action' => 'changed'], ['action' => 'removed'],
+                ['action' => 'default_set'], ['action' => 'default_cleared'],
+            ])
+        );
+        self::assertSame('Presets: 2 angelegt.', PresetDiff::summary([['action' => 'added'], ['action' => 'added']]));
+        self::assertSame('Presets: keine Änderung.', PresetDiff::summary([]));
+    }
 }
diff --git a/tests/Unit/Integrations/Divi/DiviIntegrationTest.php b/tests/Unit/Integrations/Divi/DiviIntegrationTest.php
index 73f5672..8b0970a 100644
--- a/tests/Unit/Integrations/Divi/DiviIntegrationTest.php
+++ b/tests/Unit/Integrations/Divi/DiviIntegrationTest.php
@@ -32,6 +32,7 @@ final class DiviIntegrationTest extends TestCase
         'lit/divi-node-copy',
         'lit/divi-dynamic-sources',
         'lit/divi-preset-get',
+        'lit/divi-presets-set',
     ];
 
     public function testProvidesTheDiviAbilitiesOnlyWithDivi5(): void