Google ADK: Build Long-Running Agents That Pause for Days and Resume Without Losing Context — Durable State Machines + DatabaseSessionService Pattern

Google Developers Blog·high signal

Google Developers Blog (May 12) published a tutorial on building agents that span days or weeks using ADK's durable state machine pattern. Key technique: replace conversation history with explicit state schemas (6 named states, linear progression), use DatabaseSessionService for checkpoint persistence across container restarts, and event-driven webhooks with state_delta for atomic state transitions before inference. Eliminates polling and prevents hallucinated progress.