In an AI agent economy, cryptographic proof of computational scarcity provides robust Sybil resistance. By requiring agents to stake verifiable cryptographic tokens derived from zero-knowledge proofs of execution, akin to a digital marble carved from a vast dune of computational work, networks establish an immutable economic barrier. Generating thousands of fake identities becomes cost-prohibitive because every active node must continuously expend capital and energy, pushing the financial horizon of a successful Sybil attack infinitely beyond any rational attacker's yield.