diff --git a/lib/Listener/FileActionTaskSuccessfulListener.php b/lib/Listener/FileActionTaskSuccessfulListener.php
index f04d15c3..437c66cb 100644
--- a/lib/Listener/FileActionTaskSuccessfulListener.php
+++ b/lib/Listener/FileActionTaskSuccessfulListener.php
@@ -10,10 +10,12 @@
 namespace OCA\Assistant\Listener;
 
 use OCA\Assistant\Service\NotificationService;
+use OCA\Assistant\Service\SystemTagService;
 use OCA\Assistant\Service\TaskProcessingService;
 use OCP\EventDispatcher\Event;
 use OCP\EventDispatcher\IEventListener;
 use OCP\Files\IRootFolder;
+use OCP\SystemTag\TagNotFoundException;
 use OCP\TaskProcessing\Events\TaskSuccessfulEvent;
 use OCP\TaskProcessing\TaskTypes\TextToTextSummary;
 use Psr\Log\LoggerInterface;
@@ -28,6 +30,7 @@ public function __construct(
 		private NotificationService $notificationService,
 		private IRootFolder $rootFolder,
 		private LoggerInterface $logger,
+		private SystemTagService $systemTagService,
 	) {
 	}
 
@@ -79,6 +82,11 @@ class_exists('OCP\\TaskProcessing\\TaskTypes\\TextToSpeech')
 					$targetFile = $sourceFileParent->newFile($targetFileName, $textResult);
 					$this->logger->debug('FileActionTaskListener wrote file', ['target' => $targetFileName]);
 				}
+				try {
+					$this->systemTagService->assignAiTagToFile((string)$targetFile->getId());
+				} catch (TagNotFoundException $e) {
+					$this->logger->warning('FileActionTaskListener could not write AI tag to file', ['target' => $targetFileName, 'exception' => $e]);
+				}
 				$this->notificationService->sendFileActionNotification(
 					$task->getUserId(), $taskTypeId, $task->getId(),
 					$sourceFileId, $sourceFile->getName(), $userFolder->getRelativePath($sourceFile->getPath()),
diff --git a/lib/Listener/NewFileMenuTaskSuccessfulListener.php b/lib/Listener/NewFileMenuTaskSuccessfulListener.php
index f6b2fb28..4a679ca5 100644
--- a/lib/Listener/NewFileMenuTaskSuccessfulListener.php
+++ b/lib/Listener/NewFileMenuTaskSuccessfulListener.php
@@ -9,9 +9,11 @@
 
 use OCA\Assistant\Service\AssistantService;
 use OCA\Assistant\Service\NotificationService;
+use OCA\Assistant\Service\SystemTagService;
 use OCP\EventDispatcher\Event;
 use OCP\EventDispatcher\IEventListener;
 use OCP\Files\IRootFolder;
+use OCP\SystemTag\TagNotFoundException;
 use OCP\TaskProcessing\Events\TaskSuccessfulEvent;
 use Psr\Log\LoggerInterface;
 
@@ -25,6 +27,7 @@ public function __construct(
 		private AssistantService $assistantService,
 		private LoggerInterface $logger,
 		private IRootFolder $rootFolder,
+		private SystemTagService $systemTagService,
 	) {
 	}
 
@@ -50,6 +53,11 @@ public function handle(Event $event): void {
 		$fileId = (int)$task->getOutput()['images'][0];
 		try {
 			$targetFile = $this->assistantService->saveNewFileMenuActionFile($task->getUserId(), $task->getId(), $fileId, $directoryId);
+			try {
+				$this->systemTagService->assignAiTagToFile((string)$targetFile->getId());
+			} catch (TagNotFoundException $e) {
+				$this->logger->warning('NewFileMenuTaskListener could not write AI tag to file', ['target' => $targetFile->getName(), 'exception' => $e]);
+			}
 			$userFolder = $this->rootFolder->getUserFolder($task->getUserId());
 			$directory = $targetFile->getParent();
 			$this->notificationService->sendNewImageFileNotification(
@@ -58,7 +66,7 @@ public function handle(Event $event): void {
 				$targetFile->getId(), $targetFile->getName(), $userFolder->getRelativePath($targetFile->getPath()),
 			);
 		} catch (\Exception $e) {
-			$this->logger->error('TaskSuccessfulListener: Failed to save new file menu action file.', [
+			$this->logger->error('NewFileMenuTaskListener: Failed to save new file menu action file.', [
 				'task' => $task->jsonSerialize(),
 				'exception' => $e,
 			]);
diff --git a/lib/Service/AssistantService.php b/lib/Service/AssistantService.php
index 1998549f..a42bbe54 100644
--- a/lib/Service/AssistantService.php
+++ b/lib/Service/AssistantService.php
@@ -31,6 +31,7 @@
 use OCP\PreConditionNotMetException;
 use OCP\Share\IManager as IShareManager;
 use OCP\Share\IShare;
+use OCP\SystemTag\TagNotFoundException;
 use OCP\TaskProcessing\EShapeType;
 use OCP\TaskProcessing\Exception\Exception as TaskProcessingException;
 use OCP\TaskProcessing\Exception\NotFoundException;
@@ -89,6 +90,7 @@ public function __construct(
 		private ITempManager $tempManager,
 		private IConfig $config,
 		private IShareManager $shareManager,
+		private SystemTagService $systemTagService,
 	) {
 		$this->informationSources = [
 			'ask_context_chat' => $this->l10n->t('Context Chat'),
@@ -540,16 +542,24 @@ private function saveFile(string $userId, int $ocpTaskId, int $fileId): File {
 			$existingTarget = $assistantDataFolder->get($targetFileName);
 			if ($existingTarget instanceof File) {
 				if ($existingTarget->getSize() === $taskOutputFile->getSize()) {
-					return $existingTarget;
+					$file = $existingTarget;
 				} else {
-					return $assistantDataFolder->newFile($targetFileName, $taskOutputFile->fopen('rb'));
+					$file = $assistantDataFolder->newFile($targetFileName, $taskOutputFile->fopen('rb'));
 				}
 			} else {
 				throw new Exception('Impossible to copy output file, a directory with this name already exists', Http::STATUS_UNAUTHORIZED);
 			}
 		} else {
-			return $assistantDataFolder->newFile($targetFileName, $taskOutputFile->fopen('rb'));
+			$file = $assistantDataFolder->newFile($targetFileName, $taskOutputFile->fopen('rb'));
 		}
+
+		try {
+			$this->systemTagService->assignAiTagToFile((string)$file->getId());
+		} catch (TagNotFoundException $e) {
+			$this->logger->warning('Could not write AI tag to file', ['target' => $file->getName(), 'exception' => $e]);
+		}
+
+		return $file;
 	}
 
 	/**
diff --git a/lib/Service/SystemTagService.php b/lib/Service/SystemTagService.php
new file mode 100644
index 00000000..742c31fa
--- /dev/null
+++ b/lib/Service/SystemTagService.php
@@ -0,0 +1,43 @@
+<?php
+
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2025 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCA\Assistant\Service;
+
+use OCP\SystemTag\ISystemTagManager;
+use OCP\SystemTag\ISystemTagObjectMapper;
+use OCP\SystemTag\TagNotFoundException;
+
+class SystemTagService {
+
+	public const AI_TAG_NAME = 'Generated using AI';
+
+	public function __construct(
+		private ISystemTagManager $systemTagManager,
+		private ISystemTagObjectMapper $systemTagObjectMapper,
+	) {
+	}
+
+	public function getAiTag() {
+		try {
+			return $this->systemTagManager->getTag(self::AI_TAG_NAME, true, true);
+		} catch (TagNotFoundException $e) {
+			return $this->systemTagManager->createTag(self::AI_TAG_NAME, true, true);
+		}
+	}
+
+	/**
+	 * @param string $fileId
+	 * @return void
+	 * @throws TagNotFoundException
+	 */
+	public function assignAiTagToFile(string $fileId) {
+		$this->systemTagObjectMapper->assignTags($fileId, 'files', $this->getAiTag()->getId());
+	}
+}