The short answer
In the hosted public beta, Slack needs a connection; it is not live on day one. Files and Obsidian are the live first source. After Slack is connected, Pantasso reads approved channels, threads, messages, and relevant user context that the connected Slack app is allowed to access. It preserves channel, thread, author, and timestamp details so answers can cite the original conversation. Workspace owners choose the scope; excluded or inaccessible conversations do not become Pantasso context.