Win:Computer Use

MCP server that gives Claude (and other MCP clients) human-like control of a Windows PC — with its own virtual cursor, an emergency stop, and a manager UI.

An MCP (Model Context Protocol) server that gives any MCP-capable AI client — Claude Code, Claude Desktop, custom agents, etc. — human-like control of a Windows machine.

64 tools covering mouse, keyboard, screen capture, OCR, window/app management, file I/O, HTTP, processes, audio, and a labeled on-screen cursor so you can see what the AI is doing.

The AI gets its own independent virtual cursor rendered as an always-on-top labeled overlay (an arrow + agent-name chip). Clicks default to PostMessage, so your real Windows cursor is never touched while the AI is working — you can keep using your machine alongside it.

A bundled Electron manager app lets you edit permissions, change the cursor color / agent name / motion speed, watch a live activity log, and trigger an emergency stop, without ever opening a JSON file.

Table of contents

• Why

• Highlights

• Demo

• Requirements

• Install — the easy way (recommended)

• Install — manual

• Configuration

• Tools

• How an agent typically uses it

• Caveats

• Project layout

• Contributing

• Security

• License

Related MCP server: MCP Desktop Tools

Demo

A quick tour:

1. Launch the Electron manager — setup.bat walks you through Python + deps + client registration.

2. Start your MCP client (Claude Code, Claude Desktop). The server boots; the labeled overlay cursor appears.

3. Ask the model: "Open Paint, draw a smiley face, save it to my desktop." You'll see the arrow cursor (carrying its agent-name chip) glide along Bezier curves, click via PostMessage, and announce every tool call in the Activity panel.

4. Press Ctrl+Shift+X at any time to freeze input until you resume.

Why

Anthropic ships a "computer use" tool for macOS / Linux containers but nothing turn-key for Windows. This server fills that gap with one stdio MCP process that exposes a broad, well-defined tool surface and a permission model designed for both interactive ("ask first") and autonomous ("bypass") use.

Highlights

• Independent virtual cursor — clicks go via Win32 PostMessage by default (zero real-cursor disturbance). For apps that ignore synthetic clicks (Chromium, games, Paint canvas), every mouse tool accepts use_real_cursor: true to fall back to a brief real-cursor snap.

• Human-like motion — virtual cursor animates along a cubic Bezier path with subtle jitter, not a straight line.

• Labeled overlay cursor — arrow shape + rounded chip with the agent's name (e.g. Claude). Click-through, always-on-top, multi-monitor aware. Reads live settings from state.json so changes in the Electron manager apply within ~250ms.

• Allowlist + bypass permission model — by default, the AI can only launch apps you've allowed. One flag (bypass: true) lifts that for autonomous runs.

• Native emergency stop — Ctrl+Shift+X (Win32 RegisterHotKey) freezes input tools until emergency_resume() is called. The Electron manager also has a big STOP button.

• Activity log — every tool call is appended to activity.log (JSONL); the Electron Activity panel tails it live.

• Windows OCR built-in — find_text_on_screen / click_text use Windows.Media.Ocr (no Tesseract or other binaries required).

• Screen recording — record_screen_start / _stop write an mp4 via imageio-ffmpeg.

Requirements

• Windows 10/11.

• Python 3.10+ (3.12 recommended; the official mcp SDK requires >=3.10).

• An MCP-capable client (Claude Code, Claude Desktop, etc.).

• For the Electron manager: Node.js 18+.

Install — the easy way (recommended)

git clone https://github.com/JNX03/win-computer-use
cd win-computer-use
./setup.bat        # or: ./setup.ps1

Double-click setup.bat and the Setup wizard in the Electron manager walks you through it:

1. Python 3.10+ — auto-detects py -3.12, py -3, python, or python3 on your PATH; shows the resolved interpreter.

2. Python dependencies — one click runs pip install -r requirements.txt with live output.

3. Configure your AI client — pick a tab and click Copy:

   • Claude Code: one-click "Register with Claude Code now" if the claude CLI is on PATH, otherwise a JSON snippet for ~/.claude.json.

   • Claude Desktop: JSON for %APPDATA%\Claude\claude_desktop_config.json.

   • Codex: TOML for ~/.codex/config.toml.

   • OpenCode: JSON for ~/.config/opencode/opencode.json.

   • Generic / JSON: the standard MCP stdio entry for any other client.

4. Cursor overlay (optional) — one click launches the standalone arrow cursor.

Only Node.js 18+ is required up front; the wizard handles Python + deps + MCP registration itself.

Install — manual

If you'd rather not run Electron:

./install.ps1

This picks Python 3.10+, runs pip install, seeds config, and registers with Claude Code via claude mcp add if the CLI is on PATH.

Manual MCP registration

Paste the contents of claude_mcp_snippet.json into your client's MCP config and replace REPLACE_WITH_REPO_PATH with the absolute path to this checkout. Example for ~/.claude.json:

{
  "mcpServers": {
    "win-computer-use": {
      "command": "py",
      "args": ["-3.12", "C:/path/to/win-computer-use/server.py"]
    }
  }
}

Launch the cursor overlay

The MCP server spawns the overlay automatically when it starts. To keep an overlay alive across MCP server lifecycles (useful for short claude -p runs), launch a standalone overlay — or just press the button on the Setup page:

py -3.12 -m win_computer_use.overlay --standalone

Re-launch the manager later

cd electron-manager
npm start

Or enable auto-launch with Windows on the Cursor & Agent page (uses Electron's setLoginItemSettings).

Configuration

Lives at %USERPROFILE%\.win_computer_use\config.json:

{
  "bypass": false,
  "allowed_apps": ["mspaint.exe", "msedge.exe", "calc.exe", "explorer.exe", "notepad.exe"],
  "blocked_apps": [],
  "max_screenshot_dim": 1920,
  "mouse_move_duration_s": 0.6,
  "fail_safe": true,
  "agent_name": "Claude",
  "cursor_color": "#3B82F6",
  "overlay_enabled": true,
  "showcase_mode": true,
  "emergency_hotkey": "ctrl+shift+x"
}

• bypass — true lets the AI launch any app without your approval. Use for autonomous demos; flip back to false for safer interactive use.

• allowed_apps / blocked_apps — exe basenames (case-insensitive).

• fail_safe — leave on (pyautogui.FAILSAFE); slamming the real cursor to (0, 0) aborts.

• agent_name, cursor_color, overlay_enabled, showcase_mode, mouse_move_duration_s — overlay/motion visuals.

The AI can also flip these at runtime: permission_set_bypass, permission_add_allowed_app, set_agent_name, set_cursor_color, set_speed, set_showcase_mode, overlay_show.

Tools

64 tools, grouped:

Vision — screenshot, screenshot_region, screenshot_to_file, list_monitors, list_windows, get_cursor_position, get_virtual_cursor, pixel_color

Mouse (PostMessage by default; use_real_cursor for compat) — mouse_move, mouse_move_relative, mouse_click, mouse_double_click, mouse_drag, mouse_scroll

Keyboard — keyboard_type, keyboard_press, keyboard_hotkey, keyboard_key_down, keyboard_key_up

Wait helpers — wait_seconds, wait_for_window, wait_for_text, wait_for_pixel_color

Window / app — launch_app, focus_window, open_file, get_active_window, close_window, move_window, minimize_window, maximize_window, restore_window

OCR — find_text_on_screen, click_text

Process / system — list_processes, kill_process, volume_get, volume_set, volume_mute, lock_workstation, get_battery, text_to_speech

Files / HTTP — read_text_file, write_text_file, list_directory, delete_path, http_get, download_file

Clipboard — clipboard_get, clipboard_set

Recording / macros — record_screen_start, record_screen_stop, macro_run

Cursor & overlay — set_agent_name, set_cursor_color, set_speed, set_showcase_mode, overlay_show

Permission — permission_status, permission_set_bypass, permission_add_allowed_app

Emergency — emergency_stop_status, emergency_resume

Diagnostics — get_state

See server.py for parameter signatures.

How an agent typically uses it

screenshot()
   -> AI reads the image and decides where to click.
mouse_move(x, y, duration_s=0.6)    # virtual cursor slides on a curve to the target.
mouse_click(x, y)                    # PostMessage click; your real cursor never moves.
screenshot()
   -> verify the result, or recover.

For typing: focus_window("Notepad") → keyboard_type("...").

For Paint or other apps that need real synthetic input: pass use_real_cursor: true to mouse_drag / mouse_click.

Caveats

• PostMessage clicks don't work in every app. Chromium-rendered content (Edge/Chrome page bodies), games, DirectX, and most fullscreen apps ignore synthetic window messages. Use use_real_cursor: true there.

• UAC dialogs run on the Secure Desktop and can't be interacted with by user-mode synthetic input. The user has to click "Yes" manually.

• DPI scaling: the server sets the process Per-Monitor DPI Aware so coordinates from mss match pyautogui. Multi-monitor setups with mixed scaling should use per-monitor screenshots over the virtual desktop.

• fail_safe: keep on (pyautogui.FAILSAFE). Slamming the cursor to a screen corner aborts. The bypass flag does not disable this.

Project layout

server.py                       MCP entry point (FastMCP)
win_computer_use/
  __init__.py
  permission.py                 allowlist + bypass; config file
  state.py                      shared state.json (heartbeat, virtual cursor, emergency flag)
  activity.py                   JSONL activity log
  announce.py                   @announced decorator: per-call logging + emergency gate
  winapi.py                     ctypes helpers: PostMessage clicks, RegisterHotKey
  mouse.py                      mouse_move/click/drag/scroll — virtual cursor, Bezier motion
  keyboard_io.py                type / press / hotkey
  window.py                     launch_app, focus_window, open_file
  system.py                     volume, wait, clipboard
  vision.py                     screenshot, screenshot_region, list_monitors/windows
  ocr.py                        Windows.Media.Ocr-based find_text_on_screen / click_text
  record.py                     screen recording via mss + imageio-ffmpeg
  hotkey.py                     emergency stop via winapi.RegisterHotKey
  extras.py                     Phase 3 helpers (pixel_color, waits, window mgmt, files, http, tts)
  macro.py                      macro_run — sequential tool call list
  overlay.py                    labeled cursor overlay (tkinter), runs as a separate process

electron-manager/               permissions / activity / cursor settings UI
  main.js                       Electron main: tray, single-instance, IPC
  preload.js                    contextBridge to the renderer
  renderer/index.html|app.js|styles.css

requirements.txt
install.ps1                     one-shot installer + MCP registration
config.default.json             seeded to ~/.win_computer_use/config.json on first run
claude_mcp_snippet.json         manual-register snippet
LICENSE                         MIT
.gitignore
README.md

Contributing

Issues and PRs welcome — see CONTRIBUTING.md for the ground rules and dev setup. Code of conduct: CODE_OF_CONDUCT.md.

Security

Found a security issue? Please don't open a public issue — see SECURITY.md for how to report it.

License

MIT — see LICENSE.