I built a multi-agent system without governance. Here's the 3-layer stack I wish I'd had.

Let me describe a situation you've either been in or are about to be in. You've built a multi-agent system. It works. The orchestrator dispatches tasks to specialist agents, they call external APIs, things happen. You ship it. Then, three weeks later, you discover that your payment agent processed: a $4,200 refund at 1:47am on a Saturday with no approval; that a customer's data was accessed by an agent that technically shouldn't have had that scope; and that you have absolutely zero logs to figu