Anthropic adds cross-session messaging to Claude Code so coding agents can coordinate

Anthropic shipped Claude Code version 2.1.224 on August 7, 2026, adding cross-session messaging that lets separate sessions of its command-line coding agent, on the same or different machines, send messages to each other directly.

A new SendMessage tool delivers text-only messages, and a companion ListAgents tool discovers active sessions. Messages carry no conversation history, files or permissions, and appear in the receiving session as a labeled card that links back to the sender. macOS and Linux are supported; Windows is not.

Developers increasingly run several Claude Code sessions at once across parallel Git worktrees. Direct messaging lets one session flag a breaking change to another, coordinate parallel work, or check on a long-running test run or migration without a person relaying between them.

On the same machine, messages travel over a local socket and never reach Anthropic’s servers, according to the Claude Code changelog. Cross-machine messages route through the product’s Remote Control feature.

A follow-up, version 2.1.225 released August 8, let SendMessage start a conversation with a named Remote Control session rather than only reply after being messaged first.

The feature is limited to text and does not transfer state between sessions, so coordination still depends on each session acting on the message it receives. It is a small step toward multi-agent workflows where several coding agents split a task and keep each other in sync.