Just downloaded it and mucked about. It definitely works without the cloud, because it works while I'm offline. Looking at the code, it looks like an opt-in feature where you can provide your API key to Tavily.

That said, it seems built toward "Cheat on your homework" and doesn't reliably surface information from my notes, so I uninstalled it.

Sure seems to. https://github.com/search?q=repo%3Ajohnbean393%2FSidekick%20...