nanobot/desktop/README.md

# nanobot Desktop

Mac-first desktop app for running nanobot locally with the same product UI as the browser WebUI.

For users, the desktop app is a local wrapper around nanobot: it starts the engine for you, keeps config and chat state in the platform app data directory, and uses the shared WebUI for chat, settings, apps, skills, and workspace selection.

For contributors, this folder is a native host shell. It reuses the root WebUI build at `nanobot/web/dist`; it does not copy or fork `webui/src`. Electron owns the local engine lifecycle, exposes `window.nanobotHost` to the renderer, serves the `nanobot-app://` app protocol, and proxies `/api/*` plus `/webui/bootstrap` to a private Unix socket `nanobot desktop-gateway` process.

## What To Read

- Using or trying the app from source: start with the development commands below.
- Changing desktop behavior: read [`docs/development.md`](docs/development.md).
- Adding native host capabilities: read [`docs/host-contract.md`](docs/host-contract.md).
- Keeping browser WebUI and desktop aligned: read [`docs/webui-sync.md`](docs/webui-sync.md).

## Development

This section is for contributors working from a source checkout.

```sh
cd desktop
bun run dev:webui
```

In another terminal:

```sh
cd desktop
bun run dev:app
```

`dev:app` points Electron at the Vite dev server so WebUI changes hot reload. For source checkouts, the app uses `python3` by default and injects the repo root into `PYTHONPATH`. Packaged builds look for a bundled interpreter at `Resources/nanobot-engine/bin/python3`.

## Engine Bundle

Release builds prepare `resources/nanobot-engine/` from a macOS `python-build-standalone` archive before running `electron-builder`. By default the script discovers the latest `astral-sh/python-build-standalone` CPython 3.12 `install_only` asset for the requested architecture.

```sh
cd desktop
bun run make:mac:arm64
bun run make:mac:x64
```

Useful overrides:

- `NANOBOT_DESKTOP_ARCH=arm64|x64`
- `NANOBOT_DESKTOP_PYTHON_VERSION=3.12`
- `PYTHON_STANDALONE_RELEASE=20260510`
- `PYTHON_STANDALONE_TARBALL=/path/to/archive.tar.gz`
- `PYTHON_STANDALONE_URL=https://.../cpython-...tar.gz`
- `NANOBOT_WHEELHOUSE=/path/to/wheels` to install from a locked wheelhouse

The script installs the current checkout's `nanobot-ai[api]` into the bundled runtime and writes `nanobot-engine.json` for diagnostics.

## Updating Builds

The native host does not copy the WebUI source or fork the Python agent code. A release bundle is assembled from the current repository state:

1. Build the shared WebUI:

   ```sh
   bun run build --prefix webui
   ```

   `electron-builder` packages the resulting `nanobot/web/dist` directory as `Resources/nanobot-webui`.

2. Prepare the bundled Python engine:

   ```sh
   cd desktop
   NANOBOT_DESKTOP_ARCH=arm64 bun run prepare-engine
   ```

   The script installs the current checkout's `nanobot-ai[api]` package into `resources/nanobot-engine/`, so agent, provider, tool, WebSocket, and config changes flow into the next desktop build automatically.

3. Build the desktop app and DMG:

   ```sh
   bun run make:mac:arm64
   bun run make:mac:x64
   ```

User data is not stored in the app bundle. Config, sessions, logs, workspace state, and the default workspace remain under the platform app data directory, so updating the app replaces code without overwriting local user state.

## Runtime Contract

- User data lives under Electron's platform app data directory. In development this is usually `~/Library/Application Support/@nanobot/desktop/` on macOS; packaged builds use the packaged app name.
- Fresh installs start the private engine directly. The Python desktop gateway creates the first `config.json` with defaults, then shared WebUI settings own provider, model, and credential setup.
- The gateway listens on a per-user Unix socket in the app data directory and uses a transient secret.
- The gateway starts with only the WebSocket local channel enabled and does not serve the WebUI static bundle.
- The renderer loads assets through `nanobot-app://app/...`; browser users cannot open the native UI from a localhost port.
- WebSocket traffic uses the generic `nanobot-host://engine/...` URL, is bridged over Electron IPC, and still uses the short-lived token minted by `/webui/bootstrap`.
- Host IPC only accepts the trusted app origin, and socket bridging only accepts the `nanobot-host://engine/...` scheme.
- Native WebUI responses include a restrictive Content Security Policy.
- WebUI talks only to the generic `window.nanobotHost` contract. Product-specific native behavior stays in this folder.

Generated release artifacts, node modules, and bundled runtimes remain ignored so the tracked desktop package stays source-only.

See also:

- [`docs/development.md`](docs/development.md)
- [`docs/host-contract.md`](docs/host-contract.md)
- [`docs/webui-sync.md`](docs/webui-sync.md)