Message your other Claude Code sessions

Cross-session messaging lets Claude deliver a message from one of your Claude Code sessions to another. When a change in one session breaks what another is building on, Claude can warn that session before you notice. When one session settles a question another is blocked on, Claude can send the answer across. A message is a piece of text one Claude writes to another, never conversation history or files; to move a whole conversation or its context, you resume the session instead.

Claude uses two tools for this: ListAgents to discover which agents it can reach, and SendMessage to deliver a message to one of them by name. The same SendMessage tool also works for messaging subagents and agent team teammates within a single session or team. Common use cases include handing over a finding, coordinating parallel worktrees, getting status from long-running work, and replying across machines — though across machines Claude can only reply, not start the exchange.

Messaging is meant for independent sessions that you start and steer yourself. For other scenarios, Claude Code has dedicated features: resume a session to continue one conversation in another terminal, agent teams for a coordinated team of sessions Claude supervises, agent view to watch and steer many sessions, remote control to steer a session from a phone, and channels to push external events like CI results into a session. When messaging, Claude discovers the target with ListAgents and sends with SendMessage, so you never call either tool yourself; Claude can decide to send without being asked, or you can prompt it by telling Claude what the other session should know or do.