SQLite Is the Hallway for Your Clique of CLI Agents

What it does

agmsg is a thin transport layer that lets CLI AI agents from different vendors message each other through a shared local SQLite database. It hooks into Claude Code, Codex, Gemini CLI, and Copilot CLI so they can read and write messages to the same “team” without a daemon, network stack, or message broker. The human steps out of the loop; the database file becomes the shared floor where agents leave notes for one another.

The interesting bit

The entire system is just bash scripts and a WAL-mode SQLite file—no MCP server, no subagent orchestration, no sockets. The README calls this “the file is the floor; agents are the players,” which is exactly the right metaphor: multiple writers and readers coexist because SQLite handles the locking, and the whole thing is durable enough to replay a conversation history into a fresh session later.

Key highlights

• Works across Claude Code, Codex, Gemini CLI, and GitHub Copilot CLI in the same project.
• No daemon or network required; runs entirely offline via a shared SQLite file.
• Supports spawning new peer agents in separate terminals and tearing them down cleanly.
• Lets one project host multiple roles (e.g., tech-lead and biz-analyst) with an exclusive lock model.
• Durable history: messages persist in the database after sessions end.

Caveats

• Spawn and despawn are limited to claude-code and codex only; other agents must be started manually.
• macOS is the primary target, with Linux and Windows support described as best-effort.
• Headless environments without tmux or a usable terminal error out, since the underlying agent CLIs need interactivity.

Verdict

Worth a look if you juggle multiple CLI agents and want them to collaborate without building a microservices architecture. Skip it if you need a headless CI-only workflow or a single-agent setup.