diff --git a/appinfo/routes.php b/appinfo/routes.php
index c0948b62873..0eb6c066aad 100644
--- a/appinfo/routes.php
+++ b/appinfo/routes.php
@@ -58,6 +58,9 @@
 
 		/** @see Controller\UserApiController::index() */
 		['name' => 'UserApi#index', 'url' => '/api/v1/users', 'verb' => 'POST'],
+
+		/** @see Controller\AiController::tagFile() */
+		['name' => 'Ai#tagFile', 'url' => '/ai/tag/{fileId}', 'verb' => 'POST'],
 	],
 	'ocs' => [
 		/** @see Controller\WorkspaceController::folder() */
diff --git a/composer/composer/autoload_classmap.php b/composer/composer/autoload_classmap.php
index daa77de7338..a10fd62b7d4 100644
--- a/composer/composer/autoload_classmap.php
+++ b/composer/composer/autoload_classmap.php
@@ -9,6 +9,7 @@
     'Composer\\InstalledVersions' => $vendorDir . '/composer/InstalledVersions.php',
     'OCA\\Text\\AppInfo\\Application' => $baseDir . '/../lib/AppInfo/Application.php',
     'OCA\\Text\\Command\\ResetDocument' => $baseDir . '/../lib/Command/ResetDocument.php',
+    'OCA\\Text\\Controller\\AiController' => $baseDir . '/../lib/Controller/AiController.php',
     'OCA\\Text\\Controller\\AttachmentController' => $baseDir . '/../lib/Controller/AttachmentController.php',
     'OCA\\Text\\Controller\\ISessionAwareController' => $baseDir . '/../lib/Controller/ISessionAwareController.php',
     'OCA\\Text\\Controller\\NavigationController' => $baseDir . '/../lib/Controller/NavigationController.php',
@@ -64,6 +65,7 @@
     'OCA\\Text\\Migration\\Version040100Date20240611165300' => $baseDir . '/../lib/Migration/Version040100Date20240611165300.php',
     'OCA\\Text\\Migration\\Version070000Date20250925110024' => $baseDir . '/../lib/Migration/Version070000Date20250925110024.php',
     'OCA\\Text\\Notification\\Notifier' => $baseDir . '/../lib/Notification/Notifier.php',
+    'OCA\\Text\\Service\\AiTagService' => $baseDir . '/../lib/Service/AiTagService.php',
     'OCA\\Text\\Service\\ApiService' => $baseDir . '/../lib/Service/ApiService.php',
     'OCA\\Text\\Service\\AttachmentService' => $baseDir . '/../lib/Service/AttachmentService.php',
     'OCA\\Text\\Service\\ConfigService' => $baseDir . '/../lib/Service/ConfigService.php',
diff --git a/composer/composer/autoload_static.php b/composer/composer/autoload_static.php
index ef2fa93317e..76362a01931 100644
--- a/composer/composer/autoload_static.php
+++ b/composer/composer/autoload_static.php
@@ -24,6 +24,7 @@ class ComposerStaticInitText
         'Composer\\InstalledVersions' => __DIR__ . '/..' . '/composer/InstalledVersions.php',
         'OCA\\Text\\AppInfo\\Application' => __DIR__ . '/..' . '/../lib/AppInfo/Application.php',
         'OCA\\Text\\Command\\ResetDocument' => __DIR__ . '/..' . '/../lib/Command/ResetDocument.php',
+        'OCA\\Text\\Controller\\AiController' => __DIR__ . '/..' . '/../lib/Controller/AiController.php',
         'OCA\\Text\\Controller\\AttachmentController' => __DIR__ . '/..' . '/../lib/Controller/AttachmentController.php',
         'OCA\\Text\\Controller\\ISessionAwareController' => __DIR__ . '/..' . '/../lib/Controller/ISessionAwareController.php',
         'OCA\\Text\\Controller\\NavigationController' => __DIR__ . '/..' . '/../lib/Controller/NavigationController.php',
@@ -79,6 +80,7 @@ class ComposerStaticInitText
         'OCA\\Text\\Migration\\Version040100Date20240611165300' => __DIR__ . '/..' . '/../lib/Migration/Version040100Date20240611165300.php',
         'OCA\\Text\\Migration\\Version070000Date20250925110024' => __DIR__ . '/..' . '/../lib/Migration/Version070000Date20250925110024.php',
         'OCA\\Text\\Notification\\Notifier' => __DIR__ . '/..' . '/../lib/Notification/Notifier.php',
+        'OCA\\Text\\Service\\AiTagService' => __DIR__ . '/..' . '/../lib/Service/AiTagService.php',
         'OCA\\Text\\Service\\ApiService' => __DIR__ . '/..' . '/../lib/Service/ApiService.php',
         'OCA\\Text\\Service\\AttachmentService' => __DIR__ . '/..' . '/../lib/Service/AttachmentService.php',
         'OCA\\Text\\Service\\ConfigService' => __DIR__ . '/..' . '/../lib/Service/ConfigService.php',
diff --git a/lib/Controller/AiController.php b/lib/Controller/AiController.php
new file mode 100644
index 00000000000..7e9a44ff0f2
--- /dev/null
+++ b/lib/Controller/AiController.php
@@ -0,0 +1,32 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCA\Text\Controller;
+
+use OCA\Text\Service\AiTagService;
+use OCP\AppFramework\ApiController;
+use OCP\AppFramework\Http\Attribute\NoAdminRequired;
+use OCP\AppFramework\Http\DataResponse;
+use OCP\IRequest;
+
+class AiController extends ApiController {
+	public function __construct(
+		string $appName,
+		IRequest $request,
+		private AiTagService $aiTagService,
+	) {
+		parent::__construct($appName, $request);
+	}
+
+	#[NoAdminRequired]
+	public function tagFile(int $fileId): DataResponse {
+		$this->aiTagService->tagFileAsAiGenerated($fileId);
+		return new DataResponse([]);
+	}
+}
diff --git a/lib/Service/AiTagService.php b/lib/Service/AiTagService.php
new file mode 100644
index 00000000000..92b3d3cd13e
--- /dev/null
+++ b/lib/Service/AiTagService.php
@@ -0,0 +1,42 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCA\Text\Service;
+
+use OCP\SystemTag\ISystemTagObjectMapper;
+use Psr\Log\LoggerInterface;
+
+class AiTagService {
+	public function __construct(
+		private ISystemTagObjectMapper $systemTagObjectMapper,
+		private LoggerInterface $logger,
+	) {
+	}
+
+	/**
+	 * @param int $fileId
+	 *
+	 * @return void
+	 *
+	 * @throws \Exception
+	 *
+	 * @since 34.0.0 (ISystemTagObjectMapper::assignGeneratedByAITag)
+	 */
+	public function tagFileAsAiGenerated(int $fileId): void {
+		try {
+			$this->systemTagObjectMapper->assignGeneratedByAITag((string)$fileId, 'files');
+		} catch (\Exception $e) {
+			$this->logger->warning('Failed to tag file {fileId} as AI-generated: {error}', [
+				'fileId' => $fileId,
+				'error' => $e->getMessage(),
+				'exception' => $e,
+			]);
+		}
+	}
+}
diff --git a/src/apis/ai.ts b/src/apis/ai.ts
new file mode 100644
index 00000000000..ad1a26cb4bb
--- /dev/null
+++ b/src/apis/ai.ts
@@ -0,0 +1,20 @@
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+import axios from '@nextcloud/axios'
+import { generateUrl } from '@nextcloud/router'
+
+/**
+ * tag a file as containing AI-generated content.
+ *
+ * @param fileId id of the file to tag.
+ */
+export async function markFileAsAiGenerated(fileId: number): Promise<void> {
+	try {
+		await axios.post(generateUrl(`apps/text/ai/tag/${fileId}`))
+	} catch (e) {
+		console.warn('failed to tag file as AI-generated', e)
+	}
+}
diff --git a/src/components/Editor.vue b/src/components/Editor.vue
index 8b8442567b7..305a5b0bb46 100644
--- a/src/components/Editor.vue
+++ b/src/components/Editor.vue
@@ -73,6 +73,7 @@
 		<Translate
 			:show="translateModal"
 			:content="translateContent"
+			:file-id="fileId"
 			@insert-content="translateInsert"
 			@replace-content="translateReplace"
 			@close="hideTranslate" />
diff --git a/src/components/Menu/AssistantAction.vue b/src/components/Menu/AssistantAction.vue
index f5141a6cfb6..2ce7382dea4 100644
--- a/src/components/Menu/AssistantAction.vue
+++ b/src/components/Menu/AssistantAction.vue
@@ -175,6 +175,7 @@ import TextBoxPlusOutlineIcon from 'vue-material-design-icons/TextBoxPlusOutline
 import TextShort from 'vue-material-design-icons/TextShort.vue'
 import TranslateVariant from 'vue-material-design-icons/Translate.vue'
 import DeleteOutlineIcon from 'vue-material-design-icons/TrashCanOutline.vue'
+import { markFileAsAiGenerated } from '../../apis/ai.ts'
 import { useEditor } from '../../composables/useEditor.ts'
 import { useFileProps } from '../../composables/useFileProps.ts'
 import markdownit from '../../markdownit/index.js'
@@ -373,6 +374,9 @@ export default {
 				? markdownit.render(task.output.output)
 				: task.output.output
 			this.editor.commands.insertContent(content)
+			if (this.fileId) {
+				await markFileAsAiGenerated(this.fileId)
+			}
 			this.showTaskList = false
 		},
 		async copyResult(task) {
diff --git a/src/components/Modal/Translate.vue b/src/components/Modal/Translate.vue
index ced91abd638..79f82afbf4f 100644
--- a/src/components/Modal/Translate.vue
+++ b/src/components/Modal/Translate.vue
@@ -97,6 +97,7 @@ import NcLoadingIcon from '@nextcloud/vue/components/NcLoadingIcon'
 import NcModal from '@nextcloud/vue/components/NcModal'
 import NcSelect from '@nextcloud/vue/components/NcSelect'
 import NcTextArea from '@nextcloud/vue/components/NcTextArea'
+import { markFileAsAiGenerated } from '../../apis/ai.ts'
 import { useIsMobileMixin } from '../Editor.provider.ts'
 
 export default {
@@ -118,6 +119,10 @@ export default {
 			type: String,
 			default: '',
 		},
+		fileId: {
+			type: Number,
+			default: null,
+		},
 	},
 	data() {
 		return {
@@ -231,9 +236,15 @@ export default {
 			}
 		},
 		async contentInsert() {
+			if (this.fileId) {
+				await markFileAsAiGenerated(this.fileId)
+			}
 			this.$emit('insert-content', this.result)
 		},
 		async contentReplace() {
+			if (this.fileId) {
+				await markFileAsAiGenerated(this.fileId)
+			}
 			this.$emit('replace-content', this.result)
 		},
 		autosize() {
diff --git a/tests/unit/Controller/AiControllerTest.php b/tests/unit/Controller/AiControllerTest.php
new file mode 100644
index 00000000000..f918b0920e9
--- /dev/null
+++ b/tests/unit/Controller/AiControllerTest.php
@@ -0,0 +1,52 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCA\Text\Controller;
+
+use OCA\Text\Service\AiTagService;
+use OCP\AppFramework\Http\DataResponse;
+use OCP\IRequest;
+use PHPUnit\Framework\MockObject\MockObject;
+use Test\TestCase;
+
+class AiControllerTest extends TestCase {
+	private IRequest&MockObject $request;
+	private AiTagService&MockObject $aiTagService;
+	private AiController $controller;
+
+	protected function setUp(): void {
+		parent::setUp();
+		$this->request = $this->createMock(IRequest::class);
+		$this->aiTagService = $this->createMock(AiTagService::class);
+		$this->controller = new AiController(
+			'text',
+			$this->request,
+			$this->aiTagService,
+		);
+	}
+
+	public function testTagFileReturnsEmptyDataResponse(): void {
+		$this->aiTagService->expects($this->once())
+			->method('tagFileAsAiGenerated')
+			->with(42);
+
+		$response = $this->controller->tagFile(42);
+
+		$this->assertInstanceOf(DataResponse::class, $response);
+		$this->assertSame([], $response->getData());
+	}
+
+	public function testTagFilePassesCorrectFileId(): void {
+		$this->aiTagService->expects($this->once())
+			->method('tagFileAsAiGenerated')
+			->with(99999);
+
+		$this->controller->tagFile(99999);
+	}
+}