Computer Use, driving native desktop apps

You have MCP tools that read and operate the user's real applications through the operating system's accessibility layer. This is not a browser: use it when the work lives in a desktop app (a spreadsheet, a PDF viewer, a native internal tool, a dialog box), and use playwright-cli (the web-browse skill) for web pages.

Two things to internalise before your first call:

• Address elements by index, from a snapshot you were just shown. That is the path to prefer for everything: it activates the control directly, it is checked against drift, and the mouse pointer does not move. Coordinates exist as a fallback for canvases, maps and custom-drawn UI that expose no element, see Coordinates and dragging.
• It is off unless the user turned it on (Settings → Computer Use). The full tool set runs on macOS and Windows alike. They differ in ONE way worth relaying: Windows has no per-process input, so a keystroke takes the user's keyboard focus and a coordinate click moves their real cursor. A "disabled" or "not supported" refusal is a real configuration answer, not a transient error, relay it and stop; do not retry.

The loop

1. Find the app.

computer_list_apps()

Returns the on-screen applications with their bundle ids, pids and window titles. Skip this if the user named an app you can pass straight through, app accepts a display name ("Finder", "Preview") or a bundle id ("com.apple.finder"), matched case-insensitively.

If the app you need is not running, open it:

computer_launch_app(app="Paint")