agent9

A Windows XP-themed desktop environment for 9front (Plan 9 from Bell Labs), plus a native Plan 9 LLM coding agent, plus a working web browser. All running as a single QEMU image you can boot in 15 seconds.

The Start menu shows the launcher's app list (Pi9, Rc Shell, Stats, Acme, Faces, Files, Clock, Reboot, Halt). The vtwin window behind it is running pi9 — the cyan title bar reads pi9— moonshotai/kimi-k2.5.

What's in the box

Component	Role	Lang
mxio	Window manager. Rio fork with Luna titlebars, decorations, drag, z-order, minimize/maximize/close.	C / libdraw
xena-panel	Taskbar daemon. Start button, window list, clock.	C / libdraw
launcher	Start menu popup. Plumber-backed app launching.	C
vts	Terminal session server. 9P file server multiplexing VT100 sessions; replaces st+tmux+rc with one fs at /srv/vts.	C
vtwin	libdraw frontend for vts. Reads cell diffs, paints into a rio window.	C / libdraw
pi9	Plan 9-native LLM coding agent. Bubble Tea TUI, streaming, tool calling, sessions/skills/memory, OAuth to Anthropic Pro and GitHub Copilot.	Go
NetSurf	Web browser (from netsurf-plan9).	C

pi9 in vtwin. Cyan header shows the current model and vts session id; the dashed input box is where you type. The status line tells you to set an API key with /login.

Try it now

Download agent9-v0.1.0.qcow2 (273 MB) from the Releases page, drop it next to the runner script for your OS, run.

# macOS
brew install qemu
./run-macos.sh

# Linux (KVM if available)
sudo apt install qemu-system-x86
./run-linux.sh

# Windows
# install QEMU, then double-click run-windows.bat

At first boot you'll get two text prompts. Press Enter to both. After ~15 seconds you're in the desktop. See release/RUNNING.md for details.

Status

This is v0.1.0. The basics work and are dogfooded daily. Known rough edges:

• Pi9's TUI header occasionally scrolls off-screen after a clear (Phase 12 target).
• Mouse-wheel scrolling in pi9 is implemented but not yet tested with real input devices (QMP can't simulate it cleanly).
• The launcher app list is hardcoded C. Adding entries requires a recompile. A config-file rewrite is planned.
• File manager (xfiles) is a stub. Use acme or rc for now.
• The xfiles entry in the Start menu doesn't do anything yet.

Why

Two reasons.

One: I wanted a modern coding agent on Plan 9, the way pi.dev runs on Mac/Linux. Pi is TypeScript-on-Node and Node won't run on Plan 9, so I rewrote the shape of it in Go using Bubble Tea, mirroring pi's OAuth flows, slash commands, model picker, session tree, and skills system. Then I added Plan 9-native tools that exploit primitives Linux agents can't access — plumb, walk, ns, bind, mount — so the agent can compose namespace sandboxes in single tool calls and read its own runtime environment as files.

Two: Plan 9 ships with rio, which works great for Plan 9 people and is alien for everyone else. I wanted to find out what 9front looks like wearing a familiar window manager. Turns out, perfectly fine. mxio inherits rio's tiling sweep behavior but adds chrome that people recognize: titlebars, minimize/maximize/close, taskbar, a Start button. The Luna palette is hardcoded, not themed. v0.1 isn't trying to be configurable; it's trying to be a comfortable place to land.

Architecture

  ┌─────────────────────────────────────────────────────────┐
  │ vtwin (libdraw cell-grid renderer)                      │
  │   ↓ reads /n/vts/<sess>/cells (binary diff stream)      │
  │   ↑ writes /n/vts/<sess>/cons (keystrokes)              │
  │                                                         │
  │ vts (9P session server at /srv/vts)                     │
  │   ↓ VT100 parser, cellbuf maintenance                   │
  │   ↓ ptyfork-equivalent (rfork) into rc                  │
  │                                                         │
  │ pi9 / acme / rc / netsurf / anything                    │
  │                                                         │
  │ mxio (window manager, drawn from rio.c +titlebars)      │
  │ xena-panel (taskbar; reads /dev/wsys for window list)   │
  │ launcher (start menu, plumber-driven app launch)        │
  └─────────────────────────────────────────────────────────┘

Source for each component lives in src/<name>/ with its own mkfile. Build inside the VM:

cd /sys/src/cmd/mxio && mk install

There's no cross-build from macOS — Plan 9 has no hosted toolchain.

For pi9 specifically, Go cross-compiles from any host:

cd src/pi9 && GOOS=plan9 GOARCH=amd64 go build .

Hacking on it

The QEMU image has the source under /sys/src/cmd/{mxio,vts,vtwin,xena-panel,launcher}/ ready to mk (Plan 9 build tool). Edit on the host, rsync into the VM via the included listen1 + http shuttle pattern in tools/, or just ssh in (ssh -p 2222 glenda@localhost, no password) and edit with acme.

Wiki (architecture, gotchas, per-phase write-ups for pi9 etc.) lives at wiki/. Start with wiki/index.md for a table of contents.

For day-to-day workflow patterns, see docs/development.md.

Credits

• Plan 9 from Bell Labs / 9front — the OS this all runs on.
• pi.dev — the agent shape pi9 mirrors. Source at https://github.com/earendil-works/pi.
• charm.sh — Bubble Tea / Lipgloss / Bubbles, the TUI stack pi9 builds on.
• netsurf-plan9 — the NetSurf port.

License

MIT. See LICENSE.