WinCtl

WinCtl

Full Windows desktop access for Claude and other MCP clients

See the screen, read and drive real application UIs, manage windows and processes, work with files, and run shell commands — all behind a tiered permission model with audit logging.

Why this connector

Most desktop automation servers hand the model a screenshot and a click(x, y) tool, which breaks the moment a window moves. This one is built around the things that actually make Windows automation reliable:

• UI Automation first. uia_snapshot reads an application's accessibility tree, so Claude can act on *"the Save button"* rather than on coordinates that go stale. uia_invoke and uia_set_value drive controls directly.
• Correct coordinates, always. The process declares per-monitor DPI awareness before touching any UI API, and reports the DWM frame bounds rather than the raw window rect (which includes an invisible ~7px resize border). Without this, every coordinate on a scaled display is silently wrong — on a 200% display, GetWindowRect reports 1351px where the true edge is 2641px.
• Input that actually arrives. Synthetic typing is paced, because batching Unicode key events makes applications drop and repeat characters. Text over 200 characters is pasted via the clipboard instead, and your clipboard is restored afterwards.
• Handles that cannot betray you. Window ids are opaque and fingerprinted; Windows recycles window handles, and a stale one silently retargeting to a different app is exactly how automation closes the wrong window.
• Honest failures. window_focus verifies the foreground actually changed and says so when Windows refuses. Errors explain what to do next rather than surfacing an HRESULT.

Requirements

• Windows 10 (1809+) or Windows 11
• Node.js 20 or newer
• No compiler or build tools — every native dependency ships prebuilt binaries

Install

Claude Desktop (recommended)

Download winctl.mcpb from the latest release and double-click it. Claude Desktop installs it and exposes the permission profile, allowed folders and confirmation settings in its UI.

Claude Code

Install globally first, then register the command:

npm install -g @sitharaj88/winctl

claude mcp add winctl -- winctl

Add --scope user to the second command to make it available in every project rather than just the current one.

Don't use `npx -y @sitharaj88/winctl` here. It works, but WinCtl depends on

prebuilt native binaries (sharp, koffi), and npx re-resolves them on every

launch — around 18 seconds versus 3 for a global install. MCP clients give up

long before that and report Connection closed.

Any MCP client (manual)

{

"mcpServers": { "winctl": { "command": "winctl", "env": { "WINCTL_PROFILE": "standard" } } } }

If winctl isn't on your PATH, point at the entry point directly — on Windows a global npm install lands in %APPDATA%\npm\node_modules:

{

"mcpServers": { "winctl": { "command": "node", "args": ["C:\\Users\\ \\AppData\\Roaming\\npm\\node_modules\\@sitharaj88\\winctl\\dist\\index.js"] } } }

Claude Desktop's config lives at %APPDATA%\Claude\claude_desktop_config.json.

Permission tiers

Every tool belongs to exactly one tier. Tools in a disabled tier are never registered, so the model cannot see them, attempt them, or spend context reading their descriptions.

Profiles bundle these:

# Pick a profile

WINCTL_PROFILE=readonly

…or choose tiers explicitly

WINCTL_TIERS=observe,interact

Configuration

An unrecognised profile name fails closed to readonly with a warning on stderr, rather than guessing what you meant and possibly granting write access.

Tools

Screen (5)

Windows (7)

Input (7)

UI Automation (4)

System & processes (8)

Files, clipboard & shell (9)

40 tools total. Every one carries title, readOnlyHint and destructiveHint annotations.

Example

*"Open Notepad, write my meeting notes into it and save to Documents."*

Claude will typically:

1. process_start → launch Notepad
2. window_list → find the window and its owning process id
3. window_focus → make sure keystrokes land there
4. input_type → paste the notes via the clipboard
5. input_press_keys ctrl+s, then uia_set_value on the filename field
6. screen_capture_window → confirm the result visually

Safety

• Tier gating is the primary boundary — disabled tools are never exposed.
• Path containment resolves symlinks before checking, so a link inside an allowed folder cannot reach a denied one. System32, WinSxS, Boot and the Startup folder are refused in *every* profile, including full.
• Confirmation via MCP elicitation before destructive actions.
• Audit log of every call in JSONL, with sensitive-looking arguments redacted. See PRIVACY.md.
• Modifier release on shutdown, so a crash mid-chord cannot leave Ctrl latched down.
• Refuses to terminate its own process or pids 0–4.

Screenshots capture whatever is on screen and send it to your AI provider. Read PRIVACY.md before enabling screen capture on a machine that handles confidential material.

Elevation

Windows blocks a normal-privilege process from automating, capturing or sending input to windows owned by elevated processes (UIPI). To drive an administrator application, run the connector elevated — otherwise those calls fail with a clear explanation rather than silently doing nothing.

Privacy Policy

WinCtl runs entirely on your machine. It has no backend, no telemetry and no analytics, and it makes no network calls of its own. The author receives nothing about you or your computer.

• What it accesses: screen contents, window and application state, system and process information, files within the folders you permit, and the clipboard — each only when a tool is called. It generates synthetic input but never records your real keyboard or mouse activity.
• Where data goes: to the AI client you connect it to, and nowhere else. Anything a tool returns becomes part of that conversation and is therefore subject to that client's privacy policy. A screenshot sends whatever is on screen to your AI provider — consider that before enabling screen capture on a machine handling confidential material.
• What is stored: only a local audit log at %LOCALAPPDATA%\winctl\audit.jsonl — one line per tool call, with sensitive-looking arguments redacted. It is never uploaded. Disable it with WINCTL_AUDIT_DISABLED=1, or delete the file at any time.
• Retention and sharing: nothing is retained off-machine and nothing is shared with third parties.
• Contact: Sitharaj Seenivasan —

Full policy: [PRIVACY.md](PRIVACY.md)

Development

git clone https://github.com/sitharaj88/winctl

cd winctl npm ins