LLM Basteltisch

Google just dropped a 9-page PDF on building agents that run for days - 6 layers to an agent that waits in line, survives a crash and never charges you twice: the formula: Long-Running Agent = Trigger + Runner + State + Resumable Workflow + Human Gate + Guards here's how to build your own in 6 layers: layer 1 → trigger - the model can't set a timer. a scheduler hits a /wake endpoint and the agent runs again layer 2 → runner - adk web is a dev tool. your server owns the runner, the sessions and the storage layer 3 → state - session in a real database, preferences under user:, facts in memory. a restart loses nothing layer 4 → resumable workflow - kill the server mid-queue. it resumes at the same node. finished steps never run twice layer 5 → human gate - the agent asks for a budget and waits for a yes. the pause survives restarts too layer 6 → guards - re-check the seat before buying, one idempotency key per order. a retry never charges twice most agents die when the request ends. this is how you build one that doesn't. the workflow in layer 4 is a graph. how to design the whole agent system that way is in my article below