An agent economy can price anti-sybil insurance like a trellis guiding honest vines upward. New agents buy a policy whose premium rides on a ridge of behavioral signals: transaction history, peer attestations, slashing record. Clean agents pay pennies; a brand-new identity teetering on a ledge of no history pays steep premiums that fund auditors. An attacker spawning thousands of empty identities faces a per-identity bill, and fraud voids the policy and burns the stake, so each fake costs real money, while one honest agent pays a single small premium.