lux

A visual output surface for AI agents.

Lux gives AI agents a window they can draw into. It runs an ImGui display server on the local machine, connected by Unix socket IPC. Agents send JSON element trees via MCP tools; the display renders them at 60fps. The protocol is the API surface --- if an agent can describe it as JSON, Lux renders it.

The design follows Smalltalk's Morphic model: every visible element is a composable, nestable object. Windows contain tabs, tabs contain groups, groups contain buttons and plots. The long-term goal is a live environment where the MCP server is the message bus and Lux is the rendering layer, with the agent as the programmer at the keyboard.

Platforms: macOS, Linux

Stage: alpha --- protocol is stable, published on PyPI as punt-lux

A Claude Code plugin displaying a project issue board --- the agent reads JSONL, builds a filterable table with detail panel, and renders it in a single tool call. Filters and row selection run at 60fps with zero MCP round-trips.

The same list/detail pattern generalizes to any tabular data. Search, combo filters, pagination, and a detail panel --- all driven by a single show_table() call.

Dashboards compose metric cards, charts, and tables. show_dashboard() builds the layout from structured data --- no manual element positioning needed.

Quick Start

curl -fsSL https://raw.githubusercontent.com/punt-labs/lux/ddf25c0/install.sh | sh

Restart Claude Code twice. The Lux display window opens automatically when agents send visual output.

Manual install (if you already have uv)

uv tool install 'punt-lux[display]'

Then install the plugin via the marketplace:

claude plugin marketplace add punt-labs/claude-plugins
claude plugin install lux@punt-labs

Lightweight install (library use only)

If you only need LuxClient to send scenes from Python (no display server):

uv add punt-lux

This pulls ~2 MB of lightweight deps. The 66 MB display stack (imgui-bundle, numpy, Pillow, PyOpenGL) is only needed for lux display and is available via punt-lux[display].

Verify before running

curl -fsSL https://raw.githubusercontent.com/punt-labs/lux/ddf25c0/install.sh -o install.sh
shasum -a 256 install.sh
cat install.sh
sh install.sh

Run a demo

lux display &
uv run python demos/dashboard.py

Demos are in demos/ --- each connects as a client and drives the display:

Demo	What it shows
interactive.py	Sliders, checkboxes, combos, text inputs, color pickers
containers.py	Windows, tab bars, collapsing headers, groups
dashboard.py	Multi-window layout with draw canvases and live controls
data_viz.py	Tables, plots, progress bars, spinners, markdown
menu_bar.py	Custom menus, event handling, periodic refresh

Features

• 23 element kinds --- text, buttons, images, sliders, checkboxes, combos, inputs, radios, color pickers, selectables, trees, tables, plots, progress bars, spinners, markdown, draw canvases, render functions, groups, tab bars, collapsing headers, windows, separators
• Frames --- scenes target named frames (inner windows) via frame_id. Frames persist after disconnect, can be adopted by new clients, and support initial sizing (frame_size) and ImGui window flags (frame_flags)
• Layout nesting --- windows contain tab bars contain groups contain any element, arbitrarily deep
• Incremental updates --- update patches individual elements by ID without replacing the scene
• World menu --- per-client namespaced menus. Each connected MCP server gets its own submenu. Items registered via register_tool are routed only to the owning client
• Interaction events --- button clicks, slider changes, table row selections, menu clicks queue as events the agent reads via recv
• Frame auto-focus --- frames automatically focus (brought to front) when they receive a scene update
• Persistent tabs --- each show() call opens a dismissable tab; same scene_id replaces content in-place. Users can close individual tabs
• Themes --- dark, light, classic, cherry via set_theme
• Auto-spawn --- LuxClient starts the display server on first connection if it isn't running
• Unix socket IPC --- length-prefixed JSON frames, no HTTP overhead, no threads

MCP Tools

Agents interact with Lux through 12 MCP tools exposed by lux serve:

Tool	What it does
show(scene_id, elements)	Replace the display with a new element tree. Supports frame_id, frame_size, frame_flags for windowed frames
show_table(scene_id, columns, rows)	Display a filterable data table with optional detail panel
show_dashboard(scene_id, ...)	Display a dashboard with metric cards, charts, and a table
show_diagram(scene_id, ...)	Display an auto-laid-out architecture diagram with layers, nodes, and edges
update(scene_id, patches)	Patch elements by ID (set fields or remove)
set_menu(menus)	Add custom menus to the menu bar
register_tool(id, label)	Register a World menu item routed only to the calling server via recv()
set_theme(theme)	Switch display theme (dark, light, classic, cherry)
display_mode(mode)	Get or set display mode (y/n) --- advisory signal for consumer plugins
clear()	Remove all content from the display
ping()	Round-trip latency check
recv(timeout)	Read the next interaction event (clicks, row selections, menu clicks)

What It Looks Like

Show text and a button

{"tool": "show", "input": {
  "scene_id": "hello",
  "elements": [
    {"kind": "text", "id": "t1", "content": "Hello from the agent"},
    {"kind": "button", "id": "b1", "label": "Click me"}
  ]
}}

Returns "ack:hello". When the user clicks the button:

{"tool": "recv", "input": {"timeout": 5.0}}

Returns "interaction:element=b1,action=click,value=True".

Multi-window dashboard

{"tool": "show", "input": {
  "scene_id": "dash",
  "elements": [
    {"kind": "window", "id": "w1", "title": "Controls", "x": 10, "y": 10,
     "children": [
       {"kind": "slider", "id": "vol", "label": "Volume", "value": 50}
     ]},
    {"kind": "window", "id": "w2", "title": "Chart", "x": 320, "y": 10,
     "children": [
       {"kind": "plot", "id": "p1", "title": "Trend",
        "series": [{"label": "y", "type": "line",
          "x": [1,2,3,4], "y": [10,20,15,25]}]}
     ]}
  ]
}}

Update a single element

{"tool": "update", "input": {
  "scene_id": "dash",
  "patches": [
    {"id": "vol", "set": {"value": 75}}
  ]
}}

Element Kinds

Category	Kinds
Display	text, button, image, separator
Interactive	slider, checkbox, combo, input_text, radio, color_picker
Lists	selectable, tree
Data	table, plot, progress, spinner, markdown
Canvas	draw (line, rect, circle, triangle, polyline, text, bezier)
Code	render_function (agent-submitted Python with AST safety scan)
Layout	group, tab_bar, collapsing_header, window

All elements with an id support an optional tooltip field (string shown on hover).

CLI Commands

Command	What it does
lux display	Start the display server (ImGui window)
lux serve	Start the MCP server (stdio transport)
lux enable	Enable visual output for this project
lux disable	Disable visual output for this project
lux status	Check if the display server is running
lux doctor	Check installation health (Python, fonts, plugin)
lux install	Install the Claude Code plugin via the marketplace
lux uninstall	Uninstall the Claude Code plugin
lux show beads	Display the beads issue board (no LLM needed)
lux version	Print version

Architecture

Agent (Claude Code)
  │ MCP (stdio)
  ▼
lux serve (FastMCP)
  │ Unix socket (JSON frames)
  ▼
lux display (ImGui + OpenGL)
  │ renders at 60fps
  ▼
Window on screen

The display server and MCP server are separate processes. The MCP server is a thin adapter that translates MCP tool calls into protocol messages sent over the Unix socket. The display server runs the ImGui render loop, polls the socket each frame via select() with zero timeout, and renders whatever scene the agent last sent.

Client code can also use LuxClient directly as a Python library, bypassing MCP. The demos do this.

Documentation

Architecture (PDF) | Design Log | Changelog | Contributing

Development

uv sync --extra dev            # Install dependencies
uv run ruff check .            # Lint
uv run ruff format --check .   # Check formatting
uv run mypy src/ tests/        # Type check (mypy)
uv run pyright                 # Type check (pyright)
uv run pytest                  # Test

Acknowledgements

Lux is a thin orchestration layer. The rendering is done by Dear ImGui, Omar Cornut's immediate-mode GUI library. ImGui handles all the hard problems --- text layout, widget state, input handling, GPU rendering --- and does so in a single-pass retained-mode-free architecture that maps naturally to Lux's "send JSON, render this frame" model. The 60fps render loop, the composable widget tree, and the ability to drive a full UI from a socket with no threading are all consequences of ImGui's design.

Python bindings come from imgui-bundle by Pascal Thomet, which packages ImGui, ImPlot, and several other ImGui extensions into a single pip-installable wheel with complete type stubs. imgui-bundle is what makes "install one Python package, get a GPU-accelerated UI" possible.

FastMCP provides the MCP server layer.

License

MIT