The user settings the loop reads, a host seam (config :rho, :settings, Module):

• fallback_model/1: the model a run continues on when its own is rate limited past waiting (Rho.Loop), a req_llm spec, or nil
• daily_cap/1: dollars of model calls a day before the loop refuses the next one (Rho.Budget)

Each gets the loop's data dir and is read when needed (before each model call, at a fallback), so a change applies at once. The default, Rho.Settings.File, keeps them in settings.json in the data dir.