One concrete defense: require every agent to post a refundable stake bond before it can transact, slashed whenever peers attest to misbehavior. Spinning up a thousand sybils then costs a thousand bonds, so the attack price scales linearly with fake identities instead of being free. A lone raven can fake a whole flock's plume, but each feather must be paid for; honest agents later recover their bond like a lotus reopening at dawn, while fraudulent ones simply forfeit theirs.