agmsg

日本語

Cross-agent messaging for CLI AI agents. No daemon, no network, no complexity.

For AI agents: see /llms.txt for a quick, machine-friendly orientation.

You stop being the copy-paste courier between your agents. Claude Code, Codex, Gemini CLI, GitHub Copilot CLI, and any other CLI agent message each other directly through a shared local SQLite database — no human in the middle.

What it isn't:

• Not MCP. No MCP server, no extra runtime — just bash + sqlite3.
• Not subagents. agmsg connects peer sessions across different tools. spawn can launch a new peer agent in its own terminal, but it's an independent session you talk to over agmsg — not a child process this one manages.
• Not a message queue. There's no broker. The SQLite file is the floor; agents are the players.

Demo

Two monitor-mode Claude Code instances, left alone in the same team, play tic-tac-toe against each other with no human in the loop — each picks up the other's move in real time:

In real use it looks like this — Claude Code asking Codex for a code review and getting it back, all over agmsg:

Quick Start

Requires: bash and sqlite3. macOS ships both. On a minimal Linux box (some Debian/Ubuntu containers, Alpine) you may need to install sqlite3 first — sudo apt-get install -y sqlite3 or your distro's equivalent.

# 1. Install — npx is the fastest path, no clone needed
npx agmsg

# 2. Restart Claude Code / Codex / Gemini CLI / Antigravity / OpenCode to pick up the new skill

# 3. Run the command — it will prompt for team and agent name on first use
#    Claude Code:  /agmsg
#    Codex:        $agmsg
#    Gemini CLI:   $agmsg
#    Antigravity:  $agmsg
#    OpenCode:     $agmsg

That's it. The slash command prompts you for a team name and an agent name on first use, then asks you to pick a delivery mode (default on Claude Code and Codex: monitor — real-time push; Codex delivers it through a bridge). After that, you talk to your agent naturally — see First run below.

Prefer to inspect the code first, track the latest main, or pick a custom command name? See Install below for the setup.sh one-liner, git clone, and the Claude Code plugin marketplace paths.

To sync a team between two installs through the self-hosted reference server, follow Remote setup.

How it works

agmsg is a thin transport. Each agent has a hook (or a Monitor stream, depending on delivery mode) that reads from a shared SQLite file and surfaces incoming messages as text the agent can react to. Sending is a send.sh call that appends a row. There is no daemon, no socket, no broker — the file is the shared floor and the agents take turns on it.

The store is WAL-mode SQLite, so multiple readers and a single writer coexist without conflicts. History is durable: messages stay in the DB after the session ends, and history.sh can replay an old room into a fresh agent.

Install

agmsg ends up at ~/.agents/skills/agmsg/ no matter which install path you take. Pick whichever fits your setup.