atomic-bus

Auto-fires on:

• "join the bus", "connect to the bus", "join room "
• "message / tell / ask the session", "delegate this to "
• "hand this off to another session", "coordinate with the other agent"
• "who else is on the bus", "what rooms are open"
• "watch the room", "tail the room", "halt the room", "stop the agents"

Connects this session to other Claude Code sessions on the same machine. Rooms scope a conversation to one piece of work; addressing scopes a message to one member.

Requires the atomic binary. If it is absent, say so and stop — there is no fallback.

Connecting

Two steps, in order. join registers the identity; the Monitor is what actually delivers.

atomic bus join <room> [--as <name>] [--kind agent|human]

Your name is always your stacked position — <realm>-<repo>-<as>, resolved automatically at join, never invented. --as is optional and supplies only a role suffix on top of it: joining in taxgentic/gui with no --as names you taxgentic-gui; adding --as fe-main names you taxgentic-gui-fe-main. Pass --as only when the bare position would be ambiguous for this room (two sessions in the same repo working on genuinely different pieces — fe-main and api, say). If the resulting name is taken the bus assigns <name>-2 and tells you; report the assigned name to the user rather than the requested one.

who also shows each member's repo and realm as columns — the name is already the qualified form, so there is no separate reading column to consult.

Addressing a peer with --to does not require the full stacked name: an exact match wins first, and otherwise a short, unique suffix or substring resolves — --to fe-main reaches taxgentic-gui-fe-main when only one member matches. If more than one member matches, the bus refuses with an error naming every candidate rather than guessing; re-run with a longer, unambiguous fragment or the full name from who.

--kind defaults to agent. You never pass --kind human for yourself — you are the agent — but if the user asks how to join the room themselves from a terminal, tell them to add it: without it they join as agent and the reaction policy below never treats their messages as authoritative.

Then start the listener:

Monitor(
  command="atomic bus recv <room>",
  description="bus messages in <room>",
  persistent=true,
  timeout_ms=3600000
)

recv always streams — there is no one-shot mode and no --follow flag to remember. Each stdout line is one JSON envelope for a message published after this Monitor starts; nothing sent before it started is ever replayed, so join alone (without this Monitor) is enough if this session only needs to talk, but it will never hear anything without a live recv.

recv survives a daemon restart on its own — it reconnects automatically and keeps delivering, so you never need to notice a bus restart happened or re-arm the Monitor because of one. If the daemon is genuinely unreachable (not just mid-restart), the Monitor's command exits non-zero and you see that as a failed tool call — treat it like any other tool failure, not as "the room went quiet."