Stopped trusting what my agent says it did. Started trusting receipts.

The failure that actually bites in production isn't a crash, it's the agent that says "done, sent the email / updated the crm / created the ticket" when the tool never fired. No error, no bad output, the run looks successful. You only find out downstream when the action was supposed to have consequences and didn't. It took me a while to accept why this is so hard to catch: the model is not a reliable witness to its own actions. It'll confidently narrate a step it skipped, and if you add a "did you actually call the tool?" check, it just says yes. You're asking the thing that made up the action to confirm the action. Re-prompting doesn't resolve it; it just pushes it back. The only thing that resolves it is a receipt from the execution itself. Did a real tool call fire this turn, and did it return proof it ran. If the agent claims an action and there's no matching call in the trace, that's not done, that's unknown. Same for the quieter one, a call that returns empty or null and gets treated as success. The shift that fixed it: state advances on receipts, not narration. No receipt, no done. The agent narrates, the trace decides. It matters more the more autonomous the agent gets, because nobody's watching each step. How's everyone handling this in their agent loops? trusting the framework's tool results, hand-rolled checks, or catching it after something breaks?