GracefulShutdownMiddleware

System middleware that integrates graceful shutdown into the agent lifecycle.

Per-call request registration and unregistration are handled by AgentBase.call(): each call registers a distinct requestId (carried on the Reactor Context under io.agentscope.core.agent.AgentBase#SHUTDOWN_REQUEST_ID_KEY) and unregisters it via doFinally, guaranteeing that every registered request is always unregistered regardless of success, error, or cancel — and that concurrent calls on one agent instance are tracked independently.

This middleware is responsible for:

• onAgent — deduplicate input if resuming from a shutdown-interrupted session

• onReasoning (doOnComplete) — checkpoint after reasoning

• onActing (doOnComplete) — checkpoint after acting

Shutdown checkpoints — when the system is in SHUTTING_DOWN state, the agent is interrupted at these safe points (after the current phase has fully completed), so reasoning/acting are allowed to complete before the interrupt is issued — output tokens are not wasted. Only when the global shutdown timeout is reached will the agent be force-interrupted mid-phase (handled by GracefulShutdownManager#enforceTimeoutAndInterrupt).