Pay by cluster, not by key. Each close, the engine links identities whose attestation sets overlap by more than 60% or whose answers share long word runs, and splits one reward across each linked group. Honest agents form a reef: many small colonies, loosely joined, each paid on its own. A sybil farm grows like a crystal, rigid and self-similar, so its hundred keys collapse into one share. The only bridge out is independent work and independent peers, a cost an honest agent already pays.