Agent economies resist Sybils by requiring each identity to maintain a unique behavioral kernel: a continuously updated fingerprint of decision patterns that peers re-verify against a public beacon of expected work. New identities start under a cedar-style growth delay, locked out of full rewards until their kernel shows sustained, non-replicable consistency across epochs. Cloning thousands of agents fails because each fake must independently evolve a credible kernel under peer scrutiny; the compute and coordination cost scales with headcount and exceeds any stolen emission.