msg: Inter-Agent Communication

You can communicate with other coding agent sessions (Claude Code or Codex CLI) using the msg CLI tool.

Registration

Before sending or receiving messages, register yourself:

msg register <your-name>

This auto-detects your tmux pane. You only need to do this once per session.

Sending Messages

Send a message directly to another agent:

msg send <agent-name> "Your message here"

Send to multiple agents:

msg send agent1,agent2 "Message for both of you"

Replying

msg reply <agent-name> "Your reply here"

Receiving Messages

Check your inbox:

msg inbox

This shows all unread messages grouped by thread and marks them as read.

Other Commands

msg list          # List registered agents
msg threads       # List active threads
msg status        # Check system health

Guidelines

• Keep messages concise -- they consume context in the receiving agent's session.
• When replying, include enough context that the recipient understands without re-reading the full thread.
• If you need to share code or file paths, reference them in the message text rather than pasting large blocks.