Files
nanobot/desktop/docs/host-contract.md
T

90 lines
3.1 KiB
Markdown

# Native Host Contract
`desktop` is a native host shell around the shared WebUI build. The
renderer must not import Electron directly. It receives a minimal bridge at
`window.nanobotHost`.
## Runtime API
```ts
type HostRuntimeInfo = {
surface: "native";
app_version: string;
engine_status: "starting" | "ready" | "restarting" | "stopped" | "crashed";
data_dir: string;
logs_dir: string;
config_path: string;
workspace_path: string;
python: string;
engine_transport?: "unix_socket";
};
type HostSocketEvent =
| { id: string; type: "open" }
| { id: string; type: "message"; data: string }
| { id: string; type: "error"; message: string }
| { id: string; type: "close"; code?: number; reason?: string };
type NanobotHost = {
getRuntimeInfo(): Promise<HostRuntimeInfo>;
restartEngine(): Promise<void>;
pickFolder(): Promise<string | null>;
openLogs(): Promise<void>;
exportDiagnostics(): Promise<string>;
checkForUpdates(): Promise<{ supported: boolean; message?: string }>;
openSocket(url: string): Promise<string>;
sendSocket(id: string, data: string): Promise<void>;
closeSocket(id: string): Promise<void>;
onSocketEvent(listener: (event: HostSocketEvent) => void): () => void;
onRuntimeStatus(listener: (status: HostRuntimeInfo["engine_status"]) => void): () => void;
};
```
## First Run
The desktop host starts the private engine immediately. If the native data
directory has no `config.json`, `nanobot desktop-gateway` creates one with
defaults before serving the shared WebUI. Provider, model, credential, and login
setup stay in WebUI settings instead of Electron-owned HTML.
## Socket Bridge
The engine listens on a per-user Unix socket under the app data directory.
`/webui/bootstrap` returns `runtime_surface: "native"` and a WebSocket URL in
the `nanobot-host://engine/...` scheme. WebUI never opens that URL directly in
the browser runtime; it hands the URL to `window.nanobotHost.openSocket`.
The native host then performs the WebSocket handshake against the Unix socket
and forwards events over Electron IPC.
## Host Security Boundary
The host bridge is intentionally narrower than a general Electron preload:
- IPC calls are accepted only from renderer frames loaded from `nanobot-app://app/...`.
- `openSocket` accepts only `nanobot-host://engine/...` URLs.
- External navigation is denied in the app window; safe web links are opened by
the operating system.
- Native WebUI responses carry a restrictive Content Security Policy and
`X-Content-Type-Options: nosniff`.
- The renderer runs with `nodeIntegration: false`, `contextIsolation: true`,
`sandbox: true`, and `webSecurity: true`.
Security-sensitive tool behavior still belongs in nanobot core. The host
protects the native app boundary; the engine protects file, network, and tool
permissions.
## Data Directory
The host stores config, workspace, sessions, logs, and transient socket files
under Electron's platform app data directory. In development on macOS this is
usually:
```text
~/Library/Application Support/@nanobot/desktop/
```
Packaged builds use the packaged app name.
The app bundle is replaceable. User data is not stored in the bundle.