diff --git a/lib/SetupChecks/HasOverlyLongActivities.php b/lib/SetupChecks/HasOverlyLongActivities.php
new file mode 100644
index 000000000..91bf19b67
--- /dev/null
+++ b/lib/SetupChecks/HasOverlyLongActivities.php
@@ -0,0 +1,45 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2025 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCA\Activity\SetupChecks;
+
+use OCA\Activity\AppInfo\Application;
+use OCP\IAppConfig;
+use OCP\IL10N;
+use OCP\SetupCheck\ISetupCheck;
+use OCP\SetupCheck\SetupResult;
+
+class HasOverlyLongActivities implements ISetupCheck {
+
+	public function __construct(
+		private IAppConfig $appConfig,
+		private IL10N $l10n,
+	) {
+	}
+
+	#[\Override]
+	public function getCategory(): string {
+		return 'activity';
+	}
+
+	#[\Override]
+	public function getName(): string {
+		return $this->l10n->t('Check for overly long activities');
+	}
+
+	#[\Override]
+	public function run(): SetupResult {
+		$activities = $this->appConfig->getValueInt(Application::APP_ID, 'overly_long_activities', 0);
+		if ($activities === 0) {
+			return SetupResult::success($this->l10n->t('No overly long activities detected.'));
+		}
+
+		return SetupResult::warning($this->l10n->t('There are ' . $activities . ' that generated more than 2000 characters for their content. Please check the logs for more details.'));
+	}
+}