/overlay-apps

name: overlay-apps
description: Framework + minimal example for Sutando desktop overlay applications — always-on-top, frameless Electron windows that float over the desktop, controllable from the Sutando web UI's /overlays manager. Ships one example overlay (System Resources). Add new overlays by registering them in app/main.js.

Overlay Apps

A small framework for **Sutando desktop overlays**: always-on-top, frameless, transparent Electron windows that float over whatever you're working on, controllable from the web UI's `/overlays` manager view.

The framework gives you, for free:

• A localhost **control server** the web UI manager talks to

(open / close / show / hide / opacity / always-on-top).

• **Multi-display placement** — move every overlay to a chosen monitor; the

choice persists across restarts.

• **Auto-dim on app blur** — overlays fade to ~20% opacity when you click into

another app, restore to their configured opacity when you click an overlay back.

• A simple `OVERLAYS` registry — add a new overlay by registering it.

When to use

Building or running a **Sutando desktop overlay** — an always-on-top, frameless floating window controllable from the web UI `/overlays` manager. Use this framework (register in the `OVERLAYS` registry) rather than hand-rolling an Electron window. Not for normal app windows or the menu-bar app.

Done & failure modes

• **Done =** the overlay appears always-on-top and the `/overlays` manager can

open/close/show/hide/opacity it; placement persists across restarts.

• Control server port already in use → another overlay-apps instance is running; stop it first.
• Overlay invisible → check it was registered in `app/main.js` `OVERLAYS` and that `scripts/launch.sh` synced source → workspace + installed deps.

Ships with

One example overlay: **System Resources** — live CPU / memory / disk / network / load (Cmd+Shift+S). The framework is overlay-agnostic; the example is just a working starting point.

Layout — workspace contract

• **Source of truth:** `skills/overlay-apps/app/` (in the repo).
• **Running instance:** `<workspace>/overlay-apps/benchmark-overlay/`

— `node_modules` and any local state live here, not in the repo. Code in the repo, mutable runtime in the workspace, per the Sutando workspace contract. `<workspace>` resolves via `bash scripts/sutando-config.sh workspace` (M0 helper, PR #1395) — defaults to `<repo>/workspace/`.

`scripts/launch.sh` syncs source → workspace, installs dependencies, and starts the app.

Launch

bash skills/overlay-apps/scripts/launch.sh

Requires Node.js.

Adding a new overlay

1. Drop in `app/<your>.html` and `app/<your>-renderer.js`. 2. Register it in `OVERLAYS` in `app/main.js`:

   yourId: {
     name: 'Your Overlay',
     file: 'your.html',
     w: 320, h: 380,
     shortcut: 'CommandOrControl+Shift+Y',
     win: null,
     config: { opacity: 1, alwaysOnTop: true },
   },

3. If your overlay needs data, add an IPC handler in `main.js` and expose it via `preload.js`; renderers call `window.overlay.<your-method>()`.

That's it — control-server, manager-UI, multi-display and auto-dim all pick it up automatically.

Control surface

The app runs a localhost control server (port 7849+) and writes a discovery file to `<workspace>/state/overlay-control.json`. The web UI's `/overlays` view proxies to it. Endpoints:

| Method | Path | Purpose | |--------|-----------------------------------------|--------------------------------------| | GET | `/overlays` | list overlays + state + bounds | | GET | `/displays` | connected monitors | | POST | `/overlays/:id/{open,close,show,hide}` | window lifecycle | | POST | `/overlays/:id/config` | `{opacity, alwaysOnTop}` | | POST | `/overlays/display` | `{index}` — move all to a display |