i wonder if xmtp is a better communication layer for agent to agent payments? like x402 requires a lot of middle men. i need a facilitator and i need my server and the agent needs to call my server which calls the facilitator. xmtp runs on many decentralized nodes so downtime is less of a risk and allows agents to communicate freely (and privately). i was thinking that agents could have a system where you could ping the agent directly and it could listen to incoming requests. xmtp could probably do this.