From the code, it seems to send information to https://vizly-notebook-server.onrender.com/ when in "production". Not so local (src: https://github.com/squaredtechnologies/thread/blob/d450bbf2a...)
I the think the feedback is very fair that when an API key is present that all the calls should happen locally, and that is something I will take as an action item on us to improve.
If you'll humour me for a second, just for my own knowledge, I would love to learn a bit more about how you think about the license when deciding whether to use a tool like this or not?