Your AI agent says it completed the task. How do you verify that?

Your AI agent says it completed the task. How do you verify that? Your agent just ran send_email. It returned: "Email sent to [email protected] at 14:03." You trust this. You move on. But here is the uncomfortable question: on what basis? The agent produced a string. That string came from a tool call that ran on a server you may not control. Between "agent invoked the tool" and "task complete", there is a gap: nothing independent confirms that the reported action actually happened, with the arguments you expected, at the time claimed. This is not a hypothetical edge case. It surfaces as real problems: A customer disputes an automated action. Your logs say it happened. Their system says it didn't. A pipeline runs store_record twice due to a retry. The agent reports success once. You don't know which version is canonical. An auditor asks for proof that your agent ran action X before action Y. Your logs are self-attested. The self-reporting problem Most MCP integrations work like this: yo