This guide demonstrates how to build an AI agent chat experience with a multiplayer human-in-the-loop workflow using Knock and the Cloudflare Agents SDK. The workflow involves sending approval messages to users via multiple channels, deferring tool calls, and resuming them when approvals are received. The guide showcases how Knock's workflow builder and notification engine can be used to create sophisticated cross-channel messaging for agents, while the Durable Object abstraction provides a globally addressable agent process that's easy to yield and resume back to. The serverless nature of the underlying Durable Object allows for horizontal scaling to support a large number of users with no effort.