{"service":"NexusEval","version":"0.1.0","purpose":"Machine-readable marketing QA and campaign evaluation","payment":"x402 / Base USDC","paid_endpoint":"POST /api/evaluate","price":"$0.04","input":{"objective":"lead generation","audience":"B2B SaaS marketing leaders","headline":"Example headline","copy":"Example campaign or landing-page copy","cta":"Book a demo"}}