When true, the GTK permission widget hides "Allow Always" and "Deny Always"; "Allow" / "Deny" remain (one-shot). Use for prompts whose permission_target_path is synthetic per run (e.g. network#timestamp) so persisted "Always" would not match the next request. Session-scoped storage is a separate ChatPermission.Provider concern; the widget does not add extra "for this session" buttons beyond the four allow/deny / always row. Default false: show Always buttons for stable keys.