git:20260826.0882f4a to git:20260906.22f66f9

21 added, 0 removed. Audit A to A.

---

name: computer-use

description: Control a connected desktop

compatibility: "Designed for Vellum personal assistants"

metadata:

emoji: "🖥️"

vellum:

display-name: "Computer Use"

category: "system"

activation-hints:

- "User asks the assistant to click, type, or interact with the desktop GUI directly"

- "User wants control of a desktop app with no CLI or API alternative (games, design tools, visual workflows)"

- "User wants screenshots or visual inspection of what is currently on screen"

avoid-when:

- "Task can be done via a more specific skill (gmail, calendar, contacts, terminal-sessions) or a CLI / API call"

---

This skill provides the computer_use_* action tools for controlling a

connected desktop. CU tools run through the main agent loop via HostCuProxy.

The skill is internally preactivated for conversations with a connected desktop client.

Tools in this skill are proxy tools. Execution is forwarded to a connected

desktop client and is never handled locally by the assistant.

+ ## Window-scoped observation (macOS)

+ `computer_use_observe` accepts optional `capture_window_id`, a native macOS

+ CGWindowID (not a browser tab ID or accessibility element ID). Obtain the ID

+ from a current native window inventory before using it; never guess one.

+ The native helper captures that window and its accessibility tree without

+ including secondary windows, even when another app covers the selected window.

+ A missing window must not be replaced with a desktop capture.

+ This is a **single observation**, not a session-wide privacy boundary: normal

+ click/type/scroll and other action tools still return their normal desktop

+ observations. Do not promise app-only capture for a whole control session.

+ The desktop must explicitly advertise `host_cu_window_capture` support on its

+ connection; the daemon rejects older or unsupported clients before requesting

+ any capture. Other desktop platforms reject this option.

+ The screenshot is window-relative, while action coordinates are screen points;

+ do not scale it using full-display dimensions. Prefer accessibility element IDs

+ and ensure the intended window is focused before a later action. Window-scoped

+ observation does not focus the window or confine subsequent input to that app.