Update README.md

README.md

@@ -14,4 +14,6 @@ You can install and run Livebook inside a Hugging Face Space. Here's how you can
 3. Set the secret value to a password of your choice with at least 12 characters
 4. Restart the Space
 
-Hugging Face will start Livebook inside your Space. Livebook will show you a login page, and you can use the value you set for the LIVEBOOK_PASSWORD Space secret.
+Hugging Face will start Livebook inside your Space. Livebook will show you a login page, and you can use the value you set for the LIVEBOOK_PASSWORD Space secret.
+
+There's only one caveat about running Livebook inside a Hugging Face Space; the Space's visibility setting must be public. Otherwise, Smart Cells won't work. That said, your Livebook instance will still be behind Livebook authentication since you've set the LIVEBOOK_PASSWORD secret.