create-webapp

name	create-webapp
description	Create a new webapp for Meta Display Glasses with D-pad navigation and 600x600 dark-theme display. Use when the user wants to build a new glasses app, start a project, or scaffold a webapp for smart glasses.
argument-hint	[app-type] [app-name]

Required reading

Before generating or modifying any code, read both:

• ../../references/display-guidelines.md
• ../../references/performance-guidelines.md

These define the non-negotiable display physics, input model, and performance budgets for Meta Display Glasses webapps. Do not skip — generated UI that ignores these will fail on-device.

For current Web Apps docs, use the shared Wearables MCP endpoint https://mcp.developer.meta.com/wearables and call search_webapps_docs. The endpoint does not require auth, OAuth, tokens, or custom authorization headers.

If these reference files are unavailable in an isolated eval, do not search /, home directories, or unrelated workspaces. Apply the requirements already present in this skill and continue.

If the reference files are unavailable in an isolated eval, still apply these hard performance budgets:

• Initial load under 3 seconds.
• JavaScript bundle under 500 KB gzipped.
• 60 fps for focus movement, transitions, and animations.
• Runtime memory under 128 MB.
• Fewer than 10 network requests during initial load.

Create Meta Display Glasses WebApp

Create complete webapps for Meta Display Glasses with EMG wrist-band input, D-pad navigation — including sensor integration and real API connections.

Input Model

• D-pad (Up/Down/Left/Right): Navigate focusable elements (EMG band or captouch)
• Pinch = activate: An EMG pinch fires Enter/click on the focused element — it is not a positioned click. Build focusable, keyboard-activatable UI.
• Continuous drag is opt-in: There is no free cursor by default. To receive a continuous drag stream (sliders, maps, drawing), set body { touch-action: none; } in the initial CSS — see /add-gestures.
• Back: A thumb + middle-finger back gesture (or Escape) returns to the previous screen — no back button needed
• Text entry: Standard HTML text fields open the on-glasses handwriting + voice composer on focus + tap — no SDK call needed (see /add-text-input).
• Sensors: Accelerometer, gyroscope, magnetometer, orientation via W3C Generic Sensor API

No touch input is available. The EMG wrist band translates gestures into D-pad events automatically.

Related Skills

Skill	Purpose	When to Use
/add-ui	Add screens, buttons, UI components	Expanding the app
/add-text-input	Text fields, search boxes, forms (on-glasses composer)	Any text entry
/add-gestures	Pinch-to-activate, opt-in continuous drag	Sliders, maps, drawing, games
/add-offline	Service Worker + Cache API	Work without Wi-Fi, flaky connections
/connect-api	Add API connection	Connect to REST/WebSocket APIs
/add-device-sensors	Add sensor data	Motion/orientation/GPS features
/add-local-storage	Add data persistence	Save settings, cache, state

What Gets Generated

<app-name>/
  index.html              # HTML structure with screens
  styles.css              # Dark theme with focus states, loading states, components
  app.js                  # Logic, navigation, D-pad, APIs, SDK integration
  favicon.png             # 128x128 PNG icon themed to the app idea
  manifest.webmanifest    # Web App Manifest referencing the favicon

Workflow

Step 1: Understand the Request

If the user specified a webapp type, proceed to Step 2.

If not specified, ask what they want to build. Suggest from categories in references/app-ideas.md.

Step 2: Determine Output Location

Ask where to create the webapp, or use defaults:

• ~/meta-display-glasses-webapps/<app-name>/ for new webapps
• Current directory if already in a webapp workspace

mkdir -p ~/meta-display-glasses-webapps/<app-name>

Step 3: Generate Files

Generate three files using these templates as the foundation:

1. index.html — Read templates/index.html for the base HTML structure
2. styles.css — Read templates/styles.css for the complete CSS
3. app.js — Read templates/app.js for the complete JS architecture

Key requirements for the HTML:

• Viewport: width=600, height=600
• Additive display physics: pure black (#000000) renders as transparent on the additive waveguide display. Use black only for the page background/transparent areas; visible UI surfaces such as cards, headers, rows, buttons, and panels must use dark gray tones (for example #121417, #1C1E21, or #24262B) with light text.
• Description: <meta name="description" content="..."> in the <head> with a brief, app-specific summary of what the app does. Replace the template placeholder with real copy.
• MRBD identification: <meta name="mrbd-web-app-capable" content="yes"> in the <head> to positively identify the page as a Meta Display Glasses (MRBD) compatible webapp. Keep content="yes" verbatim.
• All interactive elements: class="focusable" and tabindex="0" if not a button
• Button actions: data-action="action-name"
• Each screen is a <div class="screen"> with a unique id

Customize these sections in app.js for each app:

• CONFIG — API URLs, storage key, SDK options
• state.data — App-specific data shape
• handleAppAction() — App-specific action dispatch
• onScreenEnter() — Screen-specific data loading/rendering

Add app-specific styles to styles.css as needed, building on the template foundations.

Framework guidance:

• For new Meta Display Glasses webapps, recommend the vanilla HTML/CSS/JS scaffold from this skill as the default path.
• Advise against heavy frameworks such as React, Angular, Vue, or large UI component libraries for first-pass apps because they make the 500 KB gzipped bundle, 3 second initial load, 128 MB runtime memory, and 60 fps interaction budgets harder to hit.
• If a framework is truly required, prefer lightweight alternatives such as Preact, keep dependencies minimal, measure the gzipped production bundle early, and preserve the same D-pad focus model and display constraints.

Step 4: Generate the Favicon

Create a favicon.png themed to the app idea using the bundled pure-Python script (no dependencies — stdlib only).

Constraints (do not violate):

• PNG format. No SVG — SVG favicons are not supported.
• Resolution larger than 52×52. Default to 128×128.
• Must be referenced from both index.html (<link rel="icon">) and the Web App Manifest. The template already wires both.

How to generate:

1. Design a small concept that maps to the app idea (e.g. NBA scores → orange basketball with a "B" glyph; weather → sun/cloud; music → note shape). Pick colors that contrast on a dark background.
2. Build a JSON spec using the primitives the script supports: background (solid or vertical gradient), optional rounded plate, and layers of circle / ring / rrect / polygon / points / glyph. See the script header for the full schema.
3. Render the PNG into the app directory:

python3 <plugin-path>/skills/create-webapp/scripts/favicon_generator.py \
  --spec - --out <app-name>/favicon.png <<'EOF'
{
  "size": 128,
  "background": {"type": "gradient", "from": "#1C1E21", "to": "#0A0B0C"},
  "plate": {"color": "#FF6B35", "radius": 28, "inset": 8},
  "layers": [
    {"type": "ring", "cx": 64, "cy": 64, "r": 38, "width": 4, "color": "#1C1E21"},
    {"type": "glyph", "char": "B", "cx": 64, "cy": 64, "scale": 7, "color": "#1C1E21"}
  ]
}
EOF

4. Write manifest.webmanifest next to index.html:

{
  "name": "<App Name>",
  "short_name": "<App Name>",
  "icons": [
    { "src": "favicon.png", "sizes": "128x128", "type": "image/png" }
  ],
  "background_color": "#000000",
  "theme_color": "#000000",
  "display": "standalone"
}

The <link rel="icon"> and <link rel="manifest"> references are already present in templates/index.html — no HTML edits needed.

Step 5: For API-Connected Apps

See references/api-catalog.md for free public APIs and integration patterns.

Step 6: For Sensor Apps

Use /add-device-sensors to add motion, orientation, or GPS data to the webapp.

Step 7: For UI Components

See references/ui-components.md for reusable HTML component patterns (cards, lists, tabs, loading states).

Step 8: Verify

• All screens have .screen class and unique id
• All interactive elements have .focusable class
• Buttons have data-action attributes
• Viewport is width=600, height=600
• <head> has a <meta name="description"> tag with an app-specific summary (placeholder replaced)
• <head> has <meta name="mrbd-web-app-capable" content="yes">
• D-pad navigation works (arrow keys move focus with wrap-around)
• Enter key activates focused elements
• Escape key navigates back
• Focus ring is visible (cyan glow) on selected elements
• Loading states shown during API calls
• Error states handle API failures gracefully
• Demo mode works when sensors are unavailable
• Data persists via localStorage
• All text is readable on dark background
• Content fits within 600x600 viewport
• Scrollable lists use overflow-y: auto with max-height
• Focused elements scroll into view automatically
• favicon.png exists at the app root, is >52×52 PNG (not SVG), and is referenced from both index.html and manifest.webmanifest
• Agent surfaced the hosting/test next-step prompt (Step 10)

Step 9: Guide Next Steps

Created: ~/meta-display-glasses-webapps/<app-name>/
  index.html              (screens, structure)
  styles.css              (dark theme, focus states, loading/error states)
  app.js                  (D-pad nav, API calls, SDK integration)
  favicon.png             (themed app icon)
  manifest.webmanifest    (web app manifest)

Expand with:
  /add-ui               Add screens, buttons, UI components
  /add-text-input       Add text fields, search boxes, forms
  /add-gestures         Add sliders, drawing, maps (continuous drag)
  /add-offline          Make the app work without Wi-Fi
  /connect-api          Connect to more APIs
  /add-device-sensors   Add motion/orientation/GPS sensors
  /add-local-storage    Add data persistence

Test locally by opening index.html in a browser and using arrow keys + Enter.

Step 10: Offer a Hosting Path

After expansion options, ask the user how they want to run the app on Meta Display Glasses. The glasses load webapps via HTTPS, so the app needs to be hosted on a public URL.

Prompt the user with:

Your webapp is ready and works locally. To run it on Meta Display Glasses, it needs to be hosted on a public HTTPS URL. Two options:

• /test-on-device — deploy to a public staging URL (e.g. stage-<app>.vercel.app) for iterating
• /publish-to-vercel — publish to a stable production URL (e.g. <app>.vercel.app)

Both use Vercel (free tier works) and I can set the whole thing up for you. If you'd rather host the app yourself elsewhere, you can skip both — anywhere that serves HTTPS will work.

Do not auto-invoke either skill. Wait for the user's choice.

Speeding up iteration (optional)

Iterating on the glasses (build → install → test on-device) is slow. When that on-device round-trip is the bottleneck, offer the user a much faster off-device loop: Claude attaches to a user-launched Chromium/Edge serving the app from localhost over the Chrome DevTools Protocol (started with --remote-debugging-port=9222), then hot-reload-iterates the app and drives the D-pad user journeys each cycle — no device, no rebuild between edits. The user can also take control of the same tab and play with the app directly while iterating. Validate the final result on-device before calling it done — the fast loop is for iterating, not for proving on-device parity.

Offer this only when on-device iteration is actually slowing the user down; it's a speed-up, not the default.

Troubleshooting

Issue	Solution
Webapp doesn't load on device	Check browser console for JS errors
Focus ring not visible	Verify .focusable class on interactive elements
D-pad not navigating	Check moveFocus() handles the current screen
Enter not activating	Verify data-action attribute on element
Back navigation not working	Check navigateBack(), the Escape handler, or the back gesture
API calls failing	Check CORS headers, use proxy if needed
API data not updating	Clear cache: state.cache = {}
Sensor data not flowing	Check sensor types are valid, verify device support
Data not persisting	Verify saveData() called after state changes
Screen not showing	Check hidden class and navigateTo() call
Demo mode not working	Verify fallback code in sensor helpers

Use browser developer tools to view console.log output for debugging.