Protocol State Machine

This diagram shows the states a RUF client moves through during the application lifecycle.

State descriptions

State	Description
IDLE	Application not yet started
SESSION_CREATING	/session/create request in flight
READY	Session active, UI rendered, awaiting user input
ACTION_IN_FLIGHT	/session/action request in flight
OPTIMISTIC_NAV	Action in flight, client has speculatively applied a navigation directive
NAVIGATING	Server confirmed navigation; client is updating the screen stack
ROLLBACK	Server returned FAILED; client is restoring pre-action stack state
ERROR	Unrecoverable error — network failure after retries, or fatal server error

Notes

• The client can only be in one state at a time.
• Multiple actions may be queued, but only one is in_flight at a time. A queue implementation may cancel previous in-flight actions if a newer action supersedes them.
• The READY state is the steady state — the application spends most of its time here, waiting for the next user interaction.
• ERROR is a terminal state that typically requires user action (e.g. a retry button) or an app restart to recover from.