Since August, Claude Code sessions can talk to each other. The feature is called cross-session messaging and arrived in v2.1.224: a session finds your other sessions with ListAgents and sends one of them a message with SendMessage . What travels is only the text Claude writes for the other session, never the conversation history or files. I've been using it to build rind-ui, a headless UI component library, with two sessions that have different jobs. One is the PM. The other is the engin...