Picture an agent that answers questions about customer invoices. It has one tool, a lookup against an internal API, and a task that needs four lookups. The first two go through fine. Then the credential behind that API expires, and every call from the third one onward comes back as a 401.

What can happen next is the part that bothers me. The agent calls the tool again, and again, each time tweaking its arguments a little, as if the API had a problem with its phrasing. After a while, it gives up on the tool and writes a tidy, confident answer that covers all four customers. Nothing in that answer admits that the tool stopped working two calls in. The run just ends with a success status, and the dashboard stays green.

This article is about that quiet ending.…