How do you know when an AI agent is ready to take real actions?

I've been thinking about this as more agents move beyond chat to use tools, call APIs, update records, and trigger workflows. A demo can look great when everything goes as expected. But once an agent is connected to real systems, a small mistake can have actual consequences. I'm interested in how people here handle that transition. Do you have a specific point where you decide an agent is ready for real-world use? What do you monitor once it's running? And how do you catch situations where the agent technically completes a task but still makes the wrong decision? For those who have deployed agents with access to tools or workflows, what was the biggest thing you learned after moving from testing to actual use?