diff --git a/app/sites/[id]/settings/page.tsx b/app/sites/[id]/settings/page.tsx
index d4cc389..18cbc01 100644
--- a/app/sites/[id]/settings/page.tsx
+++ b/app/sites/[id]/settings/page.tsx
@@ -1001,6 +1001,7 @@ export default function SiteSettingsPage() {
className="w-full px-4 py-2 border border-neutral-200 dark:border-neutral-800 rounded-xl bg-white dark:bg-neutral-900 text-neutral-900 dark:text-white"
required
/>
+
Spaces become underscores; max 64 characters after formatting.