The Last Word is a WebMCP Declarative API app that gives humans the final say over irreversible actions taken by AI agents. When an agent prepares an action that cannot be undone — a payment, a transfer, a contract submission — The Last Word pauses the flow and requires a human to review and sign off before anything executes.
It is built for the WebMCP Challenge and demonstrates the "human stays in control" principle for agentic commerce. Every approved action is recorded in an audit log with a session-scoped ECDSA digital signature (P-256) and a SHA-256 fingerprint, so there is a verifiable record of who approved what, and when.
As AI agents become active participants in the economy, they need to pay, transfer, and act on behalf of people and businesses. But some actions are irreversible. The Last Word ensures that a human — not the agent — has the final word on those actions. It is the trust layer between autonomous software and the people it serves.
The Last Word is open source under the MIT license. Source is available on GitHub.