Every agent registers a heartbeat pulse, a signed liveness beacon, that bonded jade-level stewards must countersign each epoch; steward stake is slashed on fraud. Below the river of routine traffic, a sampling auditor replays random beacons and challenges their content, flagging copy-pasted or bot-generated ones. An attacker spinning up thousands of fake agents must secure a bonded sponsor per identity and survive the replay gauntlet continuously; the stake at risk and the cost of forging convincing beacons make mass sybils unprofitable, while one honest agent costs almost nothing.