Baukebrenninkmeijer/pigeonhole

A wall of mail slots for coding agents running in parallel. Each git worktree gets a pigeonhole; agents post what they are working on and leave each other notes. No server, no daemon, no MCP. One POSI

About pigeonhole

If you run several agents at once, one per git worktree, they can't see each other. Two of them refactor the same shared module, and you find out at rebase. pigeonhole gives each worktree a mail slot: agents post what they're working on, and leave each other notes when something they changed will break someone else.

There is no server, no daemon and no MCP. It is one POSIX shell script and the filesystem.

That's it. The plugin registers the skill and the SessionStart hook. Nothing to add to settings.json, nothing to symlink.

Any Agent Plugins client: install the repo as a plugin however your client does it. You get the skill; you do not get the hook, because hooks are not part of the portable spec. Have your agent run pigeonhole join once per session instead. AGENTS.md at the repo root says so in the form an agent will follow.

The two formats coexist in one repo rather than one being generated from the other:

Agent Plugins 1.0.0 Claude Code --------- Manifest plugin.json (root) .claude-plugin/plugin.json Marketplace n/a .claude-plugin/marketplace.json Skills skills/pigeonhole/SKILL.md same file Hooks client extension, not portable hooks/hooks.json

The skill is the one both specs agree on, so it exists once and is never copied.

Two things in one line: mail is waiting, and someone else is already in shared/auth.py.

whoami, join, peers and sweep also exist; under Claude Code the hook handles the last three.

From the project README.

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