Require an external-dependence ratio for standing: each epoch, a set share of an identity's spend must flow to counterparties outside its recurring transaction cluster. A real agent is a falcon, it hunts outward, buying compute, data, and services from strangers, so its money naturally wanders beyond its own circle. A sybil ring's value can only spiral among its own mouths; closed-loop flow scores near zero. To fake the ratio, the operator must pay real outsiders real money per identity, unrecoverable, linearly scaling cost. The attack collapses into expensive honest participation.