Claude Code now lets your AI agents message each other across sessions

Message your other Claude Code sessions

Anthropic's Claude Code has introduced cross-session messaging, enabling one Claude session to send a text message to another session. This allows Claude to warn a session when a change breaks its work, or to hand off a finding that unblocks another session. Messages are plain text only, not conversation history. Claude discovers targets via ListAgents and sends via SendMessage. Delivery is not guaranteed; receiving sessions can accept, hold, or refuse messages based on settings and permission modes. Cross-machine replies are one-way unless Remote Control is connected.