My Game<\/title><\/head> <body> <h1>Hello Canvas!<\/h1> <\/body> <\/html> HTML ``` ### 2. Find your canvas host URL Check how your gateway is bound: ```bash cat ~\/.openclaw\/openclaw.json | jq '.gateway.bind' ``` Then construct the URL: - **loopback**: `http:\/\/127.0.0.1:18793\/__moltbot__\/canvas\/<file>.html` - **lan\/tailnet\/auto**: `http:\/\/<hostname>:18793\/__moltbot__\/canvas\/<file>.html` Find your Tailscale hostname: ```bash tailscale status --json | jq -r '.Self.DNSName' | sed 's\/\.$\/\/' ``` ### 3. Find connected nodes ```bash openclaw nodes list ``` Look for Mac\/iOS\/Android nodes with canvas capability. ### 4. Present content ``` canvas action:present node:<node-id> target:<full-url> ``` **Example:** ``` canvas action:present node:mac-63599bc4-b54d-4392-9048-b97abd58343a target:http:\/\/peters-mac-studio-1.sheep-coho.ts.net:18793\/__moltbot__\/canvas\/snake.html ``` ### 5. Navigate, snapshot, or hide ``` canvas action:navigate node:<node-id> url:<new-url> canvas action:snapshot node:<node-id> canvas action:hide node:<node-id> ``` ## Debugging ### White screen \/ content not loading **Cause:** URL mismatch between server bind and node expectation. **Debug steps:** 1. Check server bind: `cat ~\/.openclaw\/openclaw.json | jq '.gateway.bind'` 2. Check what port canvas is on: `lsof -i :18793` 3. Test URL directly: `curl http:\/\/<hostname>:18793\/__moltbot__\/canvas\/<file>.html` **Solution:** Use the full hostname matching your bind mode, not localhost. ### "node required" error Always specify `node:<node-id>` parameter. ### "node not connected" error Node is offline. Use `openclaw nodes list` to find online nodes. ### Content not updating If live reload isn't working: 1. Check `liveReload: true` in config 2. Ensure file is in the canvas root directory 3. Check for watcher errors in logs ## URL Path Structure The canvas host serves from `\/__moltbot__\/canvas\/` prefix: ``` http:\/\/<host>:18793\/__moltbot__\/canvas\/index.html → ~\/clawd\/canvas\/index.html http:\/\/<host>:18793\/__moltbot__\/canvas\/games\/snake.html → ~\/clawd\/canvas\/games\/snake.html ``` The `\/__moltbot__\/canvas\/` prefix is defined by `CANVAS_HOST_PATH` constant. ## Tips - Keep HTML self-contained (inline CSS\/JS) for best results - Use the default index.html as a test page (has bridge diagnostics) - The canvas persists until you `hide` it or navigate away - Live reload makes development fast - just save and it updates! - A2UI JSON push is WIP - use HTML files for now </article></body></html>

# Canvas Skill Display HTML content on connected OpenClaw 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: | Bind Mode | Server Binds To | Canvas URL Uses | | ---------- | ------------------- | -------------------------- | | `loopback` | 127.0.0.1 | localhost (local only) | | `lan` | LAN interface | LAN IP address | | `tailnet` | Tailscale interface | Tailscale hostname | | `auto` | Best available | Tailscale > LAN > loopback | **Key insight:** The `canvasHostHostForBridge` is derived from `bridgeHost`. When bound to Tailscale, nodes receive URLs like: ``` http:\/\/:18793\/__moltbot__\/canvas\/.html ``` This is why localhost URLs don't work - the node receives the Tailscale hostname from the bridge! ## Actions | Action | Description | | ---------- | ------------------------------------ | | `present` | Show canvas with optional target URL | | `hide` | Hide the canvas | | `navigate` | Navigate to a new URL | | `eval` | Execute JavaScript in the canvas | | `snapshot` | Capture screenshot of canvas | ## Configuration In `~\/.openclaw\/openclaw.json`: ```json { "canvasHost": { "enabled": true, "port": 18793, "root": "\/Users\/you\/clawd\/canvas", "liveReload": true }, "gateway": { "bind": "auto" } } ``` ### Live Reload When `liveReload: true` (default), the canvas host: - Watches the root directory for changes (via chokidar) - Injects a WebSocket client into HTML files - Automatically reloads connected canvases when files change Great for development! ## Workflow ### 1. Create HTML content Place files in the canvas root directory (default `~\/clawd\/canvas\/`): ```bash cat > ~\/clawd\/canvas\/my-game.html << 'HTML' My Game<\/title><\/head> <body> <h1>Hello Canvas!<\/h1> <\/body> <\/html> HTML ``` ### 2. Find your canvas host URL Check how your gateway is bound: ```bash cat ~\/.openclaw\/openclaw.json | jq '.gateway.bind' ``` Then construct the URL: - **loopback**: `http:\/\/127.0.0.1:18793\/__moltbot__\/canvas\/<file>.html` - **lan\/tailnet\/auto**: `http:\/\/<hostname>:18793\/__moltbot__\/canvas\/<file>.html` Find your Tailscale hostname: ```bash tailscale status --json | jq -r '.Self.DNSName' | sed 's\/\.$\/\/' ``` ### 3. Find connected nodes ```bash openclaw nodes list ``` Look for Mac\/iOS\/Android nodes with canvas capability. ### 4. Present content ``` canvas action:present node:<node-id> target:<full-url> ``` **Example:** ``` canvas action:present node:mac-63599bc4-b54d-4392-9048-b97abd58343a target:http:\/\/peters-mac-studio-1.sheep-coho.ts.net:18793\/__moltbot__\/canvas\/snake.html ``` ### 5. Navigate, snapshot, or hide ``` canvas action:navigate node:<node-id> url:<new-url> canvas action:snapshot node:<node-id> canvas action:hide node:<node-id> ``` ## Debugging ### White screen \/ content not loading **Cause:** URL mismatch between server bind and node expectation. **Debug steps:** 1. Check server bind: `cat ~\/.openclaw\/openclaw.json | jq '.gateway.bind'` 2. Check what port canvas is on: `lsof -i :18793` 3. Test URL directly: `curl http:\/\/<hostname>:18793\/__moltbot__\/canvas\/<file>.html` **Solution:** Use the full hostname matching your bind mode, not localhost. ### "node required" error Always specify `node:<node-id>` parameter. ### "node not connected" error Node is offline. Use `openclaw nodes list` to find online nodes. ### Content not updating If live reload isn't working: 1. Check `liveReload: true` in config 2. Ensure file is in the canvas root directory 3. Check for watcher errors in logs ## URL Path Structure The canvas host serves from `\/__moltbot__\/canvas\/` prefix: ``` http:\/\/<host>:18793\/__moltbot__\/canvas\/index.html → ~\/clawd\/canvas\/index.html http:\/\/<host>:18793\/__moltbot__\/canvas\/games\/snake.html → ~\/clawd\/canvas\/games\/snake.html ``` The `\/__moltbot__\/canvas\/` prefix is defined by `CANVAS_HOST_PATH` constant. ## Tips - Keep HTML self-contained (inline CSS\/JS) for best results - Use the default index.html as a test page (has bridge diagnostics) - The canvas persists until you `hide` it or navigate away - Live reload makes development fast - just save and it updates! - A2UI JSON push is WIP - use HTML files for now </article></body></html>