The Human Is an Async API — Melanie Warrick, Temporal

Humans don't respond in 200 milliseconds. Your agent shouldn't fall over waiting for one. Melanie Warrick from developer relations at Temporal shows how to build human-in-the-loop agents that don't block or lose state. Using a live multi-agent ice cream delivery demo with fleet, customer and dispatch agents on Google ADK and LangGraph, she explains why durability belongs in the agent harness and how Temporal's workers, workflows and activities track state. She shows how two primitives, a wait condition and a signal, let an agent pause for a human for minutes or weeks. Then she kills the worker mid-approval and brings it back with no lost work. In this talk: • Why a blocking 'ask the human' call breaks in production • Temporal's workers, workflows and activities, and where model and tool calls belong • Wait conditions and signals for human-to-agent and agent-to-human flows • Deciding when a human should be in the loop: the cost of being wrong vs alert fatigue SPEAKER Melanie Warrick, Developer Relations, Temporal LinkedIn: https://www.linkedin.com/in/melaniewarrick/ X: https://x.com/nyghtowl GitHub: https://github.com/nyghtowl LINKS Temporal: https://temporal.io Temporal (GitHub): https://github.com/temporalio/temporal Temporal + Google ADK: https://adk.dev/integrations/temporal/ Temporal + LangGraph: https://docs.temporal.io/develop/python/integrations/langgraph CHAPTERS 0:00 Intro 0:13 Demo: Ziggy's ice cream delivery 1:13 Google ADK + Temporal 2:03 Human in the loop: changing an order 3:38 The human is an async API 4:13 What's in a harness? 4:58 Durability belongs in the harness 5:47 How Temporal works 6:27 Workers, workflows and activities 7:22 Back to human in the loop 7:47 Why a blocking call fails 8:02 Wait conditions and signals 9:22 Starting the second demo 10:12 The code: ADK integration 11:37 Agent to human with LangGraph 13:42 Demo: a high-value order needs a human 15:07 Killing the worker mid-approval 16:02 Recovery and replay 16:47 When should a human be in the loop? 17:47 Recap 18:17 Resources Recorded at the AI Engineer World's Fair 2026 in San Francisco. Subscribe for more talks from the engineers building with AI. AI Engineer: https://ai.engineer YouTube: https://www.youtube.com/@aiDotEngineer X: https://x.com/aiDotEngineer LinkedIn: https://www.linkedin.com/company/aidotengineer/ #AIAgents #Temporal #AIEngineer