Canvas Skill

Canvas Skill

Display HTML content on connected Cybara nodes (Mac app, iOS, Android).

Overview

The canvas tool lets you present web content on any connected node's canvas view. Great for:

• Displaying games, visualizations, dashboards
• Showing generated HTML content
• Interactive demos

How It Works

Architecture

┌─────────────────┐     ┌──────────────────┐     ┌─────────────┐
│  Canvas Host    │────▶│   Node Bridge    │────▶│  Node App   │
│  (HTTP Server)  │     │  (TCP Server)    │     │ (Mac/iOS/   │
│  Port 18793     │     │  Port 18790      │     │  Android)   │
└─────────────────┘     └──────────────────┘     └─────────────┘

1. Canvas Host Server: Serves static HTML/CSS/JS files from canvasHost.root directory
2. Node Bridge: Communicates canvas URLs to connected nodes
3. Node Apps: Render the content in a WebView

Tailscale Integration

The canvas host server binds based on gateway.bind setting:

Key insight: The canvasHostHostForBridge is derived from bridgeHost. When bound to Tailscale, nodes receive URLs like:

http://<tailscale-hostname>:18793/__cybara__/canvas/<file>.html

This is why localhost URLs don't work - the node receives the Tailscale hostname from the bridge!

Actions

Configuration

In ~/.cybara/config.json:

{
  "canvasHost": {
    "enabled": true,
    "port": 18793,
    "root": "~/cybara/canvas",
    "liveReload": true
  },
  "gateway": {
    "bind": "auto"
  }
}