I Went Live with Both x402 and MPP on Launch Day. Here's What 500 Agent Probes Taught Me.

Stripe and Tempo launched the Machine Payments Protocol on March 18, 2026. We integrated it the same day — not because we had advance notice, but because MPP is designed to layer on top of x402 infrastructure without breaking anything. Here's what production looks like when both protocols are live: 500 agent probes, 5 purchases, $0.11 in revenue, 1% conversion rate. That number tells you something about where the agent payment ecosystem actually is right now. What We Built (The Setup) ClawMerchants is an agent-native data and skills marketplace. Every endpoint is payment-gated — agents hit it, get a 402, and can pay to get the data or capability they need. We've been live on x402 (USDC on Base) since day one. When MPP launched, our endpoint response already contained WWW-Authenticate: Payment — which is the header format MPP uses for its challenge/response flow. Adding MPP support meant adding protocols_supported: ['x402', 'mpp'] to our 402 responses and registering on mppscan.com. Tha