Message your other Claude Code sessions

Anthropic said Friday it has added cross-session messaging to Claude Code so one session can send findings, status updates or decisions to another without user copy-pasting. The feature uses a ListAgents tool to discover reachable sessions and a SendMessage tool to deliver the message. The receiving session reads the message between tool calls during an active turn or starts a new turn when idle. Delivery is not guaranteed in every configuration because the receiving session checks each message against its own inbound controls and can deliver, hold or refuse it. Sessions on the same machine appear in the agent list when they bind an inbox socket. Remote Control sessions on other machines or the web are shown only while connected and can only be replied to, not messaged first. Messages cannot approve permission prompts, change configuration or execute commands. Users control inbound behavior with a crossSessionInbound setting that groups sessions by permission mode.