atrium — agent terminal

tmux for coding agents

A multi-agent terminal that runs your own CLIs in switchable, splittable panes with an agent-aware status bar and borders, so a whole grid of agents stays legible at a glance. Zero third-party dependencies, all the way down.

┌ 1:claude ─────────────────┐┌ 2:claude ? ───────────────┐ focused: full fidelity its agent is waiting on you: this border is yellow └───────────────────────────┘└───────────────────────────┘ atrium | 1:claude* | 2:claude? | 3:cmd- | 1 waiting | ^A c:win

why atrium

Run more than one coding agent and the terminal falls apart: you lose track of which agent is working, which is blocked waiting on you, and which finished ten minutes ago. Tabs do not help; a backgrounded agent is invisible.

atrium gives every agent a pane and reads each one's real status, working or waiting on you or idle, straight from the agent's own session, so the chrome tells you where to look. Then one human, through a couple of coordinator agents, can drive a whole bench of workers, every one a visible, killable pane. It does this with no third-party code: the pseudo-terminals, the VT parser, the screen diffing, and the status reader are all nativelite crates.

quickstart

Install

$ cargo install atrium

Set up the coordination skills

The control plane and fleets rely on two Claude Code skills. Without them a hosted agent does not know the control plane exists, so install them from the nativelite marketplace before running --allow-ctl sessions or atrium fleet up.

> /plugin marketplace add nativelite/marketplace
> /plugin install atrium@nativelite

Run

$ atrium claude          # every pane runs claude
$ atrium                 # every pane runs your shell
$ atrium -n 4 claude     # four agent panes at once, a 2x2 grid
$ atrium fleet up crew   # bring up a saved roster of named agents

Drive it with the Ctrl+A prefix

cnew window
" / %split the focused pane stacked / side-by-side
h j k lmove focus between tiles
zzoom the focused pane full-screen and back
bthe board and bus dashboard
othe overview panel (many agents at a glance)
x / qkill the focused pane / quit atrium

concepts

Windows and panes

A single or zoomed pane renders in passthrough, so a TUI looks pixel-exact. Two or more panes render tiled, each in its own emulator, composited into one screen.

Agent-aware status

Read-only, status only, never conversation text. The pane chrome shows who is blocked:

waiting on you idle / prompt focused

Credential identity

Run an agent under a vault key or a WIF profile with --identity. Only the name is ever shown, never the secret.

Zero dependencies

Built on the nativelite stack: pty, rawterm, ansi, vterm, agsess. No third-party code anywhere in the tree.

coordinating agents

With --allow-ctl, a pane can spawn, send to, observe, and kill other agent panes, turning atrium from a viewer of agents into a runtime for them. Because every agent is a visible, killable pane with a status border, the whole hierarchy stays legible, which opaque subagents are not.

$ atrium --allow-ctl --trust claude
$ atrium ctl spawn --role lead -- claude
$ atrium ctl send lead "Own the parser rewrite. Split it across two ICs."
$ atrium ctl status     # roll-up of your subtree
$ atrium ctl list       # the live org chart

It stands on three pieces: ctl (spawn / send / status / kill), the board (a shared key-to-fields source of truth), and the bus (a topic pub/sub event stream with fyi and decision-needed urgencies). Trust governs how hands-off it runs.

documentation

The full guide, in the terminal theme:

Architecture

the zero-dependency stack and passthrough-first rendering.

Agent-aware status

how atrium reads working / waiting / idle, and what it can and cannot see.

Credential identity

per-pane keys and WIF profiles via --identity, names never secrets.

Fleets and mass-spawn

saved rosters and the atrium.fleet.json spec.

The control plane

the full ctl reference, the board, and the bus.

Trust and security

the trust ladder and the seven-point security model.

Orphans and reaping

how a pane's whole process tree is torn down, safely.

Overview and README

install, quickstart, reference tables, design and scope.