John developed the MerchantGuard AI-powered compliance infrastructure for the coinbase/x402 repository, focusing on merchant risk scoring, security scanning, and agent certification. He integrated three gated API products—GuardScore, GuardScan, and Mystery Shopper—into the ecosystem directory, deploying them on the Base mainnet with USDC-based access control. The implementation leveraged AI integration and API development skills, using JSON for data interchange. GuardScan featured a three-layer security scanner covering 100 patterns, while Mystery Shopper enabled agent certification through a ten-probe system. The work addressed compliance and security needs for merchants, demonstrating depth in compliance infrastructure within a one-month development period.