punt-lux 0.5.2

The paintbrush for Claude. A visual output surface for AI agents — diagrams, tables, images, and interactive controls.

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

Quick Start

curl -fsSL https://raw.githubusercontent.com/punt-labs/lux/1f3b83c/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

Then install the plugin via the marketplace:

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

Verify before running

curl -fsSL https://raw.githubusercontent.com/punt-labs/lux/1f3b83c/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

• 22 element kinds --- text, buttons, images, sliders, checkboxes, combos, inputs, radios, color pickers, selectables, trees, tables, plots, progress bars, spinners, markdown, draw canvases, groups, tab bars, collapsing headers, windows, separators
• 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
• Menu bar --- built-in Lux/Theme/Window menus, plus agent-extensible custom menus via set_menu
• Interaction events --- button clicks, slider changes, menu selections queue as events the agent reads via recv
• 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 six MCP tools exposed by lux serve:

Tool	What it does
show(scene_id, elements)	Replace the display with a new element tree
update(scene_id, patches)	Patch elements by ID (set fields or remove)
set_menu(menus)	Add custom menus to the menu bar
clear()	Remove all content from the display
ping()	Round-trip latency check
recv(timeout)	Read the next interaction event (clicks, changes)

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)
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 status	Check if the display server is running
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

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