Claude Code Adds Cross-Session Messaging on macOS and Linux

Anthropic has updated Claude Code so separate coding sessions can message each other directly, removing the need to manually copy context between Terminal windows.

The feature shipped in Claude Code version 2.1.224, released Friday for macOS and Linux.

How the new messaging tools work

Two new tools power cross-session messaging: ListAgents, which finds other active sessions running on the Mac, and SendMessage, which delivers the message. A session that receives a message sees it as a labeled card with a link back to the sender.

According to Anthropic's documentation, only text passes between sessions — not conversation history, files, or permissions. A session can warn another when a change breaks something it depends on, or pass along an answer another session is waiting for. An incoming message cannot approve a permission request or change a session's settings on its own.

How it differs from subagents and Agent Teams

The feature sits alongside Claude Code's existing subagents and Agent Teams tools, but it connects sessions a user is already running separately on their Mac rather than sessions Claude spawns and manages itself. Messages between sessions on the same Mac stay local and never reach Anthropic's servers.

Between different machines, messaging works only as a reply through Remote Control, the feature that connects a Mac terminal to the Claude apps for iOS and Android.

Availability

Cross-session messaging requires macOS or Linux with Claude Code version 2.1.224 or later and is not available on Windows. It was released alongside 31 other changes in the same release, including a new claude self-hosted-runner command for Team and Enterprise plans.