canvas-os

// Canvas as an app platform. Build, store, and run rich visual apps on the OpenClaw Canvas.

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updated:March 4, 2026

SKILL.mdreadonly

SKILL.md Frontmatter

namecanvas-os

descriptionCanvas as an app platform. Build, store, and run rich visual apps on the OpenClaw Canvas.

homepagehttps://www.clawhub.ai/fraction12/canvas-os

metadata[object Object]

Canvas OS

Canvas as an app platform. Build, store, and run rich visual apps on the OpenClaw Canvas.

Philosophy

You are an OS. Canvas is the window. Apps are built locally and run on Canvas.

Rich HTML/CSS/JS UIs — not just text. Full interactivity, animations, live data.

Quick Commands

Command	What Jarvis Does
"Open [app]"	Start server, navigate Canvas, inject data
"Build me a [type]"	Create app from template, open it
"Update [element]"	Inject JS to modify live
"Show [data] on canvas"	Quick A2UI display
"Close canvas"	Stop server, hide Canvas

How It Works

Key principle: Apps run on Canvas, not in a browser tab. Canvas is your UI window.

Canvas Loading Methods

Canvas has security restrictions that block file path access. Three methods work:

Method	When to Use	Pros	Cons
Localhost Server	Complex apps, external assets	Full browser features	Requires port management
Direct HTML Injection	Quick displays, demos	Instant, no server needed	No external assets, size limit
Data URLs	Small content	Self-contained	Unreliable on some systems

❌ Does NOT work: file:///path/to/file.html (blocked by Canvas security)

📖 See: CANVAS-LOADING.md for detailed guide + troubleshooting

Helper script: canvas-inject.py — Formats HTML for direct injection

1. Apps are HTML/CSS/JS files

~/.openclaw/workspace/apps/[app-name]/
├── index.html    # The UI (self-contained recommended)
├── data.json     # Persistent state
└── manifest.json # App metadata

2. Serve via localhost

cd ~/.openclaw/workspace/apps/[app-name]
python3 -m http.server [PORT] > /dev/null 2>&1 &

3. Navigate Canvas to localhost

NODE="Your Node Name"  # Get from: openclaw nodes status
openclaw nodes canvas navigate --node "$NODE" "http://localhost:[PORT]/"

Important: This opens the app on Canvas (the visual panel), NOT in a browser.

4. Agent injects data via JS eval

openclaw nodes canvas eval --node "$NODE" --js "app.setData({...})"

Note: The openclaw-canvas:// URL scheme has issues in current OpenClaw versions. Use http://localhost: instead.

Opening an App

What this does: Displays the app on Canvas (the visual panel), not in a browser tab.

Method 1: Localhost Server (Recommended for Complex Apps)

Full sequence:

NODE="Your Node Name"
PORT=9876
APP="my-app"

# 1. Kill any existing server on the port
lsof -ti:$PORT | xargs kill -9 2>/dev/null

# 2. Start server
cd ~/.openclaw/workspace/apps/$APP
python3 -m http.server $PORT > /dev/null 2>&1 &

# 3. Wait for server
sleep 1

# 4. Navigate Canvas
openclaw nodes canvas navigate --node "$NODE" "http://localhost:$PORT/"

# 5. Inject data
openclaw nodes canvas eval --node "$NODE" --js "app.loadData({...})"

Method 2: Direct HTML Injection (For Quick Displays)

When to use: File paths don't work in Canvas (security sandboxing). Data URLs can be unreliable. Use this for instant displays without localhost.

# Example using canvas tool
canvas.present(url="about:blank", target=node_name)

html_content = """<!DOCTYPE html>
<html>
<head>
    <style>
        body { background: #667eea; color: white; padding: 40px; }
        .card { background: white; color: #333; padding: 30px; border-radius: 16px; }
    </style>
</head>
<body>
    <div class="card">
        <h1>Your Content Here</h1>
    </div>
</body>
</html>"""

# Escape backticks and inject
js_code = f"""document.open();
document.write(`{html_content}`);
document.close();"""

canvas.eval(javaScript=js_code, target=node_name)

Key limitation: File paths (file:///path/to/file.html) are blocked in Canvas for security. Always use localhost or direct injection.

Building Apps

App API Convention

Every app should expose a window.app or window.[appname] object:

window.app = {
  // Update values
  setValue: (key, val) => {
    document.getElementById(key).textContent = val;
  },
  
  // Bulk update
  loadData: (data) => { /* render all */ },
  
  // Notifications
  notify: (msg) => { /* show toast */ }
};

Two-Way Communication

Apps send commands back via deep links:

function sendToAgent(message) {
  window.location.href = `openclaw://agent?message=${encodeURIComponent(message)}`;
}

// Button click → agent command
document.getElementById('btn').onclick = () => {
  sendToAgent('Refresh my dashboard');
};

Templates

Dashboard

Stats cards, progress bars, lists. Self-contained HTML.

Default port: 9876
API: dashboard.setRevenue(), dashboard.setProgress(), dashboard.notify()

Tracker

Habits/tasks with checkboxes and streaks. Self-contained HTML.

Default port: 9877
API: tracker.setItems(), tracker.addItem(), tracker.toggleItem()

Quick Display (A2UI)

For temporary displays without a full app:

openclaw nodes canvas a2ui push --node "$NODE" --text "
📊 QUICK STATUS

Revenue: \$500
Users: 100

Done!
"

Port Assignments

App Type	Default Port
Dashboard	9876
Tracker	9877
Timer	9878
Display	9879
Custom	9880+

Design System

:root {
  --bg-primary: #0a0a0a;
  --bg-card: #1a1a2e;
  --accent-green: #00d4aa;
  --accent-blue: #4a9eff;
  --accent-orange: #f59e0b;
  --text-primary: #fff;
  --text-muted: #888;
  --border: #333;
}

Best Practices

Self-contained HTML — Inline CSS/JS for portability
Dark theme — Match OpenClaw aesthetic
Expose app API — Let agent update via window.app.*
Use IDs — On elements the agent will update
Live clock — Shows the app is alive
Deep links — For two-way communication

Troubleshooting

App opens in browser instead of Canvas?

Make sure you're using openclaw nodes canvas navigate, not just open
Canvas navigate targets the Canvas panel specifically

"Not Found" on Canvas?

File paths don't work: Canvas blocks file:/// URLs for security (sandboxing)
Data URLs may fail: Use direct HTML injection via canvas eval + document.write() instead
For localhost: Verify server is running: curl http://localhost:[PORT]/
Check port is correct
Use http://localhost: not openclaw-canvas:// (URL scheme has issues)

Canvas shows "Not Found" even with correct URL?

This is a security boundary: Canvas can't access local filesystem
Solution: Use Method 2 (Direct HTML Injection) from "Opening an App" section
Or serve via localhost (Method 1)

App not updating?

Check window.app API is defined: openclaw nodes canvas eval --js "typeof window.app"
Verify JS eval syntax: single quotes inside double quotes

Server port already in use?

Kill existing: lsof -ti:[PORT] | xargs kill -9

Helper Scripts

canvas-inject.py

Python helper for direct HTML injection (Method 2).

# Example usage in Python
from canvas_inject import inject_html_to_canvas

html = open("my-dashboard.html").read()
commands = inject_html_to_canvas(html, node_name="Your Node")

# Then use canvas tool with these commands
canvas.present(**commands["step1_present"])
canvas.eval(**commands["step2_inject"])

Or just follow the pattern manually (see Method 2 in "Opening an App").

Requirements

OpenClaw with Canvas support (macOS app)
Python 3 (for http.server)
A paired node with canvas capability