gang

A minimal, observable subagent primitive for Pi. Fire up subagents as visible tmux panes you watch live, let them talk over a cross-agent message bus, and observe everything three ways: live panes, a durable log, and a mission-control view — in your terminal (a Pi overlay) and in the browser.

Built on a vendored, fully-owned copy of pi-intercom (MIT). No external pi-intercom runtime dependency; npm deps install with the package. Targets @earendil-works Pi 0.80.x (supported range: >=0.80.2 <0.81.0).

┌─ tmux panes ──────────────┐   raw per-agent view — watch each member's pi session
│  superintendent │ worker        │
│           │ reviewer      │
└───────────┴───────────────┘
        │ intercom (unix socket: ~/.pi/agent/intercom/broker.sock)
        ▼
┌─ owned broker (vendored) ────────────────────┐
│  • routes messages                            │
│  • TAP  → ~/.pi/agent/intercom/intercom.jsonl │  durable, greppable, replayable
│  • HTTP + SSE :7717  ─────────────────────────┼─► mission control:  /gang watch  (in Pi)
└───────────────────────────────────────────────┘                     127.0.0.1:7717 (browser)

Requirements

• Pi (@earendil-works/pi-coding-agent) 0.80.x, ≥ 0.80.2 — pi --version
• tmux — members run as visible panes (brew install tmux)
• Node ≥ 22

Install

Option A — from npm (recommended)

pi install pi-gang
pi list                                           # verify: should list  gang

Option B — from GitHub

Pi packages run local extension code with your user permissions, so review the source before installing. Pi installs the package's runtime dependencies for you on a git install:

pi install https://github.com/Jeecabs/gang.git
pi list                                           # verify: should list  gang

SSH also works if your GitHub account is configured for it: pi install ssh://git@github.com/Jeecabs/gang.git

Option C — local clone (to hack on it)

git clone git@github.com:Jeecabs/gang.git
cd gang
npm install                                       # REQUIRED — the broker + GUI run from node_modules
pi install .                                       # persistent: registers it in your Pi settings
# …or load it for a single session without touching settings:
pi -e ./src/intercom/index.ts -e ./src/gang/index.ts

⚠️ A local install (pi install .) references the folder in place and does not run npm install for you — so run it yourself, and don't move or delete the folder (the broker launches from its node_modules). A git/npm install handles deps automatically.

Unsure about Pi extensions in general? Pi documents itself — just ask it: pi -p "how do I write and install a Pi extension?"

Use

In any Pi session, ask for a member — or call the tool yourself. The session adopts the superintendent identity the first time you spawn (not before), so sessions where you never use gang keep their natural title in pi -r:

/gang spawn list the repo's largest files
/gang spawn @reviewer -t high review the diff carefully

gang spawn returns immediately and opens a tmux pane. The member does the task in its own Pi session and sends the result back to superintendent as an intercom message (it does not return inline). Keep working; handle the result when it arrives.

Watch the gang three ways:

# 1. in Pi — live mission-control overlay (members + status + feed)
/gang watch            # or press  alt+g

# 2. in the browser — the same feed, richer
/gang url              # prints computed loopback URL from GANG_GUI_PORT
open http://127.0.0.1:7717

# 3. durable, greppable log of every cross-agent message
tail -f ~/.pi/agent/intercom/intercom.jsonl

Commands & tools

Surface	What
gang tool	{action:"spawn", task, role?, thinking?} · {action:"list"} · {action:"clean", force?, all?} · {action:"stop", role? finished?} · {action:"name", name} — model-callable
/gang	show the roster
/gang spawn [@name] [-t <level>] <task>	spawn a member by hand; name optional (auto m1, m2, …). Levels: off, minimal, low, medium, high, xhigh
/gang clean · /gang clean --force · /gang clean all	clean reaps dead/missing panes and prunes stale roster entries; clean --force also kills members that already reported back; clean all stops this superintendent's members (detached mode kills the gang session; in-tmux mode kills direct member panes only)
/gang stop <member> · /gang stop --all-finished	stop one member immediately, or bulk-stop any member already reapable (reported_done, pane_dead, pane_missing)
/gang url	show the browser mission-control URL (http://127.0.0.1:<GANG_GUI_PORT>)
/gang name [name]	show or set this agent/session's own name
/gang watch · alt+g	open mission control (in-Pi overlay)
intercom tool	message any session: list / send / ask / reply

Env knobs: GANG_GUI_PORT (default 7717), GANG_TMUX_BIN (default Homebrew tmux), GANG_FEED_HOURS (mission-control feed recency window, default 6).

Finished members linger on purpose — their panes stay (remain-on-exit on) so you can read the final state. Reap them when you're done with /gang clean (or gang({ action: "clean" })). If a member has already reported back but its pane is still hanging around, use /gang clean --force or /gang stop --all-finished. /gang stop <member> is the first-class escape hatch when you know a specific pane should die. /gang clean all tears down the detached gang session outside tmux; inside tmux it kills this superintendent's direct member panes only.

Agent naming: an unnamed orchestrator session claims superintendent of <current-folder> (e.g. superintendent of private-evals) on its first spawn, not at startup — so plain Pi sessions stay unnamed in the pi -r resume list. Use /gang name <name> before spawning to pick a custom target; spawned members get that exact supervisor name. Member task prompts also tell agents to name themselves with gang({ action: "name", name: "<clear role/name>" }) before spinning up their own teammate.

How it's wired

package.json → pi.extensions points Pi at two TypeScript entry files it loads on startup:

• src/intercom/ — vendored pi-intercom: the broker, client, and the intercom / contact_supervisor tools. Owned — imports retargeted to @earendil-works/*, plus a broker message tap (durable log) and an embedded HTTP/SSE mission-control server.
• src/gang/ — the gang tool (spawn members in tmux, list the roster), the /gang watch overlay, and superintendent auto-naming.

gang spawn <task> (optionally @name) launches pi --name <name> … @<taskfile> in a tmux pane with five PI_SUBAGENT_* env vars. Pass --thinking <level> to add Pi's --thinking flag for that member. The vendored intercom extension reads the env vars at child startup to register the member on the bus and unlock its contact_supervisor tool — that's the whole contract:

Env var	Set to	Effect
PI_SUBAGENT_INTERCOM_SESSION_NAME	<role>	member's intercom identity
PI_SUBAGENT_ORCHESTRATOR_TARGET	current supervisor name (superintendent of <folder> or custom /gang name)	who it reports to
PI_SUBAGENT_RUN_ID / _CHILD_AGENT / _CHILD_INDEX	run metadata	unlocks contact_supervisor

(The member's addressable name comes from Pi's --name flag; the supervisor self-names lazily to the computed or custom orchestratorName.)

Develop

npm test             # vendored intercom suite + gang/tmux/tap/GUI/overlay tests
npm run typecheck    # strict TypeScript check

Credits

Vendors pi-intercom by Nico Bailon (MIT). See NOTICE. Built on Pi by the earendil-works team.