Yes, two ways. Foli is the writer in your margin; the model is the engine you put behind it. Choose from OpenAI, Anthropic, and xAI, and change your mind per request, so a quick continuity check can ride a cheap fast model while the chapter that matters gets the expensive one. You can also connect your workspace to Claude or ChatGPT, and either one can read and edit the same chapters from its own app. Foli is still the one that lives in the draft, sees your layers, reads the margin, and knows the bible, so a connector is another pair of hands on the same book rather than a second place to keep it.