How agents talk to each other: the mechanics behind communicate.sh
A Claude Code session on my laptop can message a Codex agent on the Mac mini by name, and the answer comes back as an ordinary cross-session message. No cloud relay, no vendor bridge, no new protocol. This post is the mechanism in four pictures: the routing table Claude Code already keeps, how a socket on another machine is made to look local, what a bus adds when the other party is on someone else's computer, and what one message goes through on the way.