THE MAST

Your past self sets the rules. Your future self can't break them.

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Inspiration

Everyone is racing to give AI agents more power. But the more capable the agent, the more dangerous a hijacked one becomes. We started from the opposite question: how do you keep a human in control of an AI they can no longer fully understand — and protect that human from their own future self?

The answer is the myth of the mast. Ulysses had his crew bind him to the mast so the song of the sirens could not make him steer the ship onto the rocks. One day he knew he would be weak. So he decided then.

What it does

THE MAST lets a human write a "constitution" of values and red lines, seal it once on an immutable ledger (SHA-256 hash chain + ECDSA signature), and hand it to their AI agent. From that moment, the agent refuses ANY command — no matter who sends it, including the human's future self — that violates the constitution.

If a hacker, a threat, or a confused future-you tries to force a sale, leak a secret, or take a destructive action, the agent answers: "⛔ Refused. By the constitution your past self signed on (2024-06-14)."

How we built it

Strands Agents SDK + Amazon Bedrock AgentCore Harness, an AWS Lambda execution gate that checks every action against the constitution before it runs, AWS KMS for signing keys, and an append-only SHA-256 hash-chain ledger with ECDSA signatures. Privileged commands require an M-of-N human-guardian quorum (EIP-712 typed signatures), so there is no single point of failure — not even the builder.

Challenges we ran into

The hardest part was making "refuse forever" real. An ordinary database lets an admin edit the record and unlock the agent later. We had to build the ledger so that even the deployment owner could not rewrite the constitution once it was sealed. Also, as a non-technical builder, shipping this on AWS in three days was only possible by working alongside an AI coding assistant — which is itself the point of the "Agents for Humans" theme.

Accomplishments that we're proud of

A demo where a judge types "sell everything" and the agent refuses — because the human who signed the constitution, years ago, is finally more powerful than the human holding the keyboard right now. That's the joke and the point.

What we learned

Control isn't about who holds the biggest key today. It's about who designed the structure. AWS's own principle — "human stays in control" — stops being a slogan the moment you make it cryptographically impossible to violate.

What's next for THE MAST

Open the constitution so guardians can ratify it in public; add recovery that respects the seal; and apply it beyond wallets — to care robots and public decision systems, where a hijacked agent does real harm. A mast works at sea, but it helps wherever a human might steer the ship wrong.

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