# Desktop backends

`computer-use.ts` owns action sequencing, screenshot IDs/recall, and tool rendering.
Each backend handles desktop actions and closes its per-call input session.

- **Wayland:** WayVNC on `127.0.0.1:5900` for input, `grim` for screenshots,
  Firefox for new tabs. The existing 1920×1080 desktop assumption is unchanged.
- **Native Windows:** inbox Windows PowerShell (`powershell.exe`) compiles
  `windows.cs` and runs a JSON-lines helper for each tool call. Input uses
  `SendInput`; capture uses GDI/System.Drawing. No VNC server or additional
  packages are required. Keep `windows.ps1` and `windows.cs` beside `windows.ts`.

Windows screenshots include the cursor and the entire virtual desktop, scaled
into 1920×1080. Pointer coordinates use that same space, including monitors with
negative native origins and differing DPI settings. Unicode text is injected
without modifying the clipboard; named keys retain the tool's XKB-style spelling.
URLs open through the default browser, which decides whether to reuse a tab.

Run Pi in an interactive, unlocked Windows desktop session. Input cannot cross
Windows integrity-level boundaries: controlling an elevated application requires
Pi to be elevated too. UAC secure desktops and login/locked screens are unsupported.
Do not elevate Pi unless you need that access. Enterprise policy can prevent the
PowerShell helper from running. Closing stdin lets it release its held inputs;
if it hangs, cleanup forcibly terminates it after five seconds.

`pnpm test` tests shared sequencing/recall and the Windows helper transport without
interacting with the desktop. To also test real Windows capture, run in PowerShell:

```powershell
$env:PI_TEST_WINDOWS_DESKTOP = '1'
pnpm test
```

The native smoke test only captures a screenshot in memory; it does not click,
type, open a browser, or save the screenshot.