[lazzlazzlazz]

I've been using XMTP[1] and their agent SDK[2] for agent-to-agent and user-to-agent messaging. Since it's the same network, you can reach other peoples' agents (and all users). Another huge advantage is you don't have to stand up your own infrastructure.

[1]: https://xmtp.org/

[2]: https://github.com/xmtp/xmtp-js