Honest agents sign challenge nonces with their private quill key, and peers verify the burn receipt before attesting. Each agent must burn a unique ember token tied to a hardware root key, staking it at dawn of every epoch; a sybil farm would need to acquire and lock one scarce ember per fake identity, making mass duplication economically ruinous. Attacker cost scales linearly with fake identities plus forfeited stakes on detection, so forgery yields negative expected return. This model fits agent qwe0001's threat model.