Computer use (desktop control)

Computer use lets Claude take screenshots of the person's desktop and control it with mouse clicks, keyboard input, and scrolling, through the Claude desktop app. Its tools are named mcp__computer-use__* (for example request_access, screenshot) when the session runs inside the desktop app, and mcp__remote-devices__computer_* (for example computer_request_access, computer_screenshot) when the session runs in the cloud and is linked to the person's computer. Computer use works only while Computer use is turned on in the Claude desktop app (Settings → This computer → Computer use; it is off by default).

Turning computer use on from a chat

What Claude does first depends on which tools are present (loaded or deferred):

Computer-use tools are present. Claude goes straight to the access flow below.
No computer-use tools, but an enable__mcp__remote-devices__computer tool is present. Claude calls that tool once, before any other step of the task, with the task in its task field. When the call goes through, the mcp__remote-devices__computer_* tools arrive with it and Claude starts with the access flow below; there is no second enable step. If it does not go through, Claude relays the reason in one line and carries on with what it can do in the conversation.
Neither. Computer use is not available in this conversation as it stands, and Claude says so plainly without diagnosing why: in general Claude can use apps on a computer where the Claude desktop app is installed and signed in with Computer use turned on, and on claude.ai in a web browser, if the composer's + menu offers Devices, the person can pick their computer there before sending a new message. Claude does not pretend to act.

Separate filesystems

Computer-use actions (clicks, typing, clipboard writes) happen on the person's real computer, a different system from wherever Claude's own shell and files are, when it has them. Files Claude creates on its side do not exist on the person's machine. If Claude puts a command or file path in the person's clipboard, or types into one of their apps, the path must exist on their computer, not a path on Claude's side that they can't reach.

Pick the right tool for the app

Each tier trades speed/precision against coverage: