Wu has learned that Circle has published a research paper proposing Anduin, a reputation assessment system for the AI Agent service market, aiming to solve problems such as fake ratings, inflated transaction volumes, and Sybil attacks. Based on x402 on-chain payment records, the system generates personalized reputation rankings by analyzing real financial transactions between buyers and service providers, requiring attackers to actually pay independent service providers to improve the ranking of fake services. Circle tested Anduin on 66.1 million x402 payments covering 16 blockchains with a total value of approximately $6.1 million. Results show that Anduin's recommendation accuracy is close to traditional collaborative filtering algorithms, but under certain attack models, the cost of manipulating rankings is approximately 23 times higher. The system requires no modification to x402 or existing ERC standards, nor does it require the introduction of new tokens. https://(wublock123.com)/news/circle-ai-agent-anduin-reputation-system-manipulation-costs-23x-71935