desktop-touch-mcp

日本語

Computer-use MCP server for Windows. Lets Claude, Cursor, or any MCP client see and operate your Windows 10/11 desktop — screenshots, UI Automation, Chrome CDP, keyboard / mouse, terminal — with semantic discover-then-act targeting that avoids pixel-coordinate guessing, and per-action perception guards that catch wrong-window typing before it happens.

npx -y @harusame64/desktop-touch-mcp

32 tools, native Rust engine (UIA in 2 ms), zero-config PowerShell fallback, full CJK support, MIT licensed. Add the snippet above to your Claude / Cursor / VS Code Copilot config and Claude can drive Notepad, Excel, Chrome, Windows Terminal, and any other app on your machine.

Why this over pixel-clicking? Two ideas run through every tool: discover-then-act — desktop_discover returns interactive entities with short-lived leases instead of raw coordinates, so desktop_act operates on what you mean, not where it was — and per-action perception guards that verify the target window's identity and bounds before input lands, catching wrong-window typing and stale-coordinate clicks before they happen.

Under the hood: an 82× average speedup from the Rust native engine (UIA focus queries in 2 ms, SSE2-accelerated image diffing at 13–15×), with a transparent PowerShell fallback when the engine is absent. The npm launcher fetches only the GitHub Release tag matching the installed version and verifies the Windows runtime zip before extraction.

Features

• ⚡ High-performance Rust Native Core — The UIA bridge and image-diff engine are written in Rust (napi-rs + windows-rs) and loaded as a native .node addon. Direct COM calls from a dedicated MTA thread eliminate PowerShell process spawning — getFocusedElement completes in 2 ms (160× faster), and getUiElements returns full trees in ~100 ms with a batch BFS algorithm that minimizes cross-process RPC. Image-diff operations use SSE2 SIMD for 13–15× throughput. When the native engine is unavailable, every function transparently falls back to PowerShell — zero config required.
• 🎯 Set-of-Marks (SoM) visual fallback — Games, RDP sessions, and non-accessible Electron apps return clickable elements even when UIA is completely blind. screenshot(detail="text") automatically detects UIA sparsity and activates a Hybrid Non-CDP pipeline: Rust-powered grayscale + bilinear upscale → Windows OCR → clustering → red bounding-box annotation with numbered badges ([1], [2]…). Two parallel representations returned: a visual PNG for spatial orientation and a semantic elements[] list with clickAt coords — no CDP required.
• 🔁 One-call confirmation on visual-only targets — On UIA-blind targets (Electron, PWAs, games, custom canvases, RDP windows), desktop_act can fold the post-action confirmation into its own response: an optional roiCapture carrying a PNG crop of just the region that changed plus a lease-less preview of the controls now visible there. The agent confirms what its click did and finds the next target without a separate desktop_state + screenshot. On visual-only targets it is on by default for a visible change (returnCapture:"on-change"); pass returnCapture:"never" to suppress it, or "always" to force it. Never attached on structured targets (browser/CDP, UIA-rich native), where desktop_state is cheaper and exact — so those responses are unchanged.
• LLM-native design — Built around how LLMs think, not how humans click. run_macro batches multiple operations into a single API call; diffMode sends only the windows that changed since the last frame. Minimal tokens, minimal round-trips.
• Reactive Perception Graph — Register a lensId for a window or browser tab, pass it to action tools, and get guard-checked post.perception feedback after each action. It reduces repeated screenshot / desktop_state calls and prevents wrong-window typing or stale-coordinate clicks.
• Full CJK support — Uses Win32 GetWindowTextW for window titles, avoiding nut-js garbling. IME bypass input supported for Japanese/Chinese/Korean environments.
• 3-tier token reduction — detail="image" (~443 tok) / detail="text" (~100–300 tok) / diffMode=true (~160 tok). Send pixels only when you actually need to see them.
• 1:1 coordinate mode — dotByDot=true captures at native resolution (WebP). Image pixel = screen coordinate — no scale math needed. With origin+scale passed to mouse_click, the server converts coords for you — eliminating off-by-one / scale bugs.
• Browser capture data reduction — grayscale=true (~50% size), dotByDotMaxDimension=1280 (auto-scaled with coord preservation), and windowTitle + region sub-crops help exclude browser chrome and other irrelevant pixels. Typical reduction for heavy captures: 50–70%.
• Chromium smart fallback — detail="text" on Chrome/Edge/Brave auto-skips UIA (prohibitively slow there) and runs Windows OCR. hints.chromiumGuard + hints.ocrFallbackFired flag the path taken.
• UIA element extraction — detail="text" returns button names and clickAt coords as JSON. Claude can click the right element without ever looking at a screenshot.
• Auto-dock CLI — window_dock(action='dock') snaps any window to a screen corner with always-on-top. Set DESKTOP_TOUCH_DOCK_TITLE='@parent' to auto-dock the terminal hosting Claude on MCP startup — the process-tree walker finds the right window regardless of title.
• Emergency stop (Failsafe) — Move the mouse to the top-left corner (within 10px of 0,0) to immediately terminate the MCP server.

Requirements

Note: nut-js native bindings require the Visual C++ Redistributable. Download from Microsoft if not already installed.

Installation

npx -y @harusame64/desktop-touch-mcp

The npm launcher resolves runtime strictly by npm package version. For package X.Y.Z, it fetches only GitHub Release tag vX.Y.Z, downloads desktop-touch-mcp-windows.zip, verifies its SHA256 digest, and only then expands it under %USERPROFILE%\.desktop-touch-mcp. Verified cached releases are reused on later runs.

Set DESKTOP_TOUCH_MCP_HOME to override the cache root directory.

On a shared or CI network? The first run reads the GitHub Releases API to locate the runtime zip. The anonymous limit is 60 requests/hour per IP, which a shared public address (CI runners, office NAT) can exhaust before your download even starts. Set GITHUB_TOKEN (or GH_TOKEN) in the environment and the launcher authenticates the request, raising the limit to 5,000 requests/hour. No token is needed on an ordinary home connection.

Running the launcher from a source checkout? A source build's bin/launcher.js carries a placeholder integrity hash (sha256: "PENDING") instead of a finalized one. Rather than download and run an unverified runtime, the launcher fails closed — this guard stops an accidentally published or unfinalized launcher from silently starting unverified code. Published npm releases always ship a real SHA256, so end users never see this. If you are intentionally running the launcher from source, set DESKTOP_TOUCH_MCP_ALLOW_UNVERIFIED=1 to skip integrity verification (development only).

Register with Claude CLI

Add to ~/.claude.json under mcpServers:

{
  "mcpServers": {
    "desktop-touch": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "@harusame64/desktop-touch-mcp"]
    }
  }
}

No system prompt needed. The command reference is automatically injected into Claude via the MCP initialize response's instructions field.

Register with other clients (HTTP mode)

Clients that require an HTTP endpoint (GPT Desktop, VS Code Copilot, Cursor, etc.) can use the built-in Streamable HTTP transport:

npx -y @harusame64/desktop-touch-mcp --http
# or with a custom port:
npx -y @harusame64/desktop-touch-mcp --http --port 8080

The server starts at http://127.0.0.1:23847/mcp (localhost only). Register the URL in your MCP client settings. A health check is available at http://127.0.0.1:<port>/health.

In HTTP mode the system tray icon shows the active URL and provides quick-copy and open-in-browser shortcuts.

Development install

git clone https://github.com/Harusame64/desktop-touch-mcp.git
cd desktop-touch-mcp
npm install

Build after install:

npm run build

For a local checkout, register the built server directly:

{
  "mcpServers": {
    "desktop-touch": {
      "type": "stdio",
      "command": "node",
      "args": ["D:/path/to/desktop-touch-mcp/dist/index.js"]
    }
  }
}

Note: Replace D:/path/to/desktop-touch-mcp with the actual path where you cloned this repository.

Tools (31 Optimized Tools)

📖 Full Reference: docs/system-overview.md — Exhaustive guide on parameters, return schemas, and coordinate math.

🌐 World-Graph V2 (Primary Path)

👁️ Observation & State

⌨️ Input & Control

🌐 Browser CDP (Chrome/Edge/Brave)

🛠️ Utilities & Workflow

📊 Office (Excel)

Standard workflow (v1.0.0)

The v2 World-Graph surface (desktop_discover / desktop_act) is the recommended dispatch path. The four-call shape works for native apps, browsers, and terminals identically.

desktop_state          → orient: focused window/element, modal, attention signal
desktop_discover       → find actionable entities (returns lease + windows[])
desktop_act(lease, …)  → act on entity (returns attention + post.perception)
desktop_state          → confirm the world changed as expected

Clicking — priority order:

browser_click(selector)               → Chrome / Edge (CDP, stable across repaints)
desktop_act(lease, action='click')    → native / dialog / visual (entity-based; use after desktop_discover)
click_element(name | automationId)    → native UIA fallback if desktop_act returns ok:false
mouse_click(x, y, origin?, scale?)    → pixel last resort; origin+scale from dotByDot screenshots only

Recovery hints — read response.attention after every observation and response.warnings[] on desktop_discover / desktop_act. Common reasons:

• lease_expired / lease_generation_mismatch / lease_digest_mismatch / entity_not_found → re-call desktop_discover
• modal_blocking → response.blockingElement (when present) names the blocking modal; dismiss via click_element(name=blockingElement.name) then retry
• entity_outside_viewport → scroll(action='to_element' | 'raw'), then re-call desktop_discover
• executor_failed → fall back to click_element / mouse_click / browser_click

Lease lifecycle:

• Each desktop_discover response carries softExpiresAtMs (≈ 60 % of the TTL window). Past that timestamp the LLM should consider re-calling desktop_discover even though the lease is still technically valid — lease.expiresAtMs is the only correctness wall.
• TTL adapts to view mode (action/explore/debug), entity count, and response payload size. Cap is 60 s.
• Set DESKTOP_TOUCH_DISABLE_FUKUWARAI_V2=1 to fall back to the v1 tool surface (get_windows / get_ui_elements / set_element_value) for troubleshooting only — V2 is the recommended default.

Terminal command completion (until)

terminal(action='run') sends a command, waits for it to complete, and reads the output in one call. How it decides "complete" is controlled by until:

Anchoring caveat (#384): a command whose final line has no trailing newline glues the marker to the next prompt with no line boundary (printf X → Xuser@host:~$), so an end-anchored pattern (X\s*\n / X$) can never bind. For completion use mode:'exit'; for content matching use a bare marker (no \n/$). mode:'pattern' also accepts an optional quietMs settle fallback: until:{mode:'pattern', pattern, quietMs:1000} completes with reason:'quiet' (no matchedPattern) once output is stable for that long without a match — instead of hanging until timeoutMs. It is opt-in (omit quietMs to keep waiting for the pattern; long commands with mid-run silent gaps are unaffected).

until:{mode:'exit'} — real completion + exit code

The heuristic modes can misfire on the common "append a sentinel" idiom (some-task; echo DONE matched by DONE): the sentinel also shows up in the echoed command line, and for multi-line commands there is no reliable way to tell that echo apart from real output. mode:'exit' removes the guesswork — the server appends its own completion marker whose printed form differs from its typed form, so it never matches the echoed command (even for multi-line input), and it returns the real process exit code:

terminal({
  action: 'run',
  windowTitle: 'pwsh',
  input: 'npm run build',
  until: { mode: 'exit', shell: 'powershell' },
})
// → completion: { reason: 'exited', exitCode: 0, elapsedMs: … }
//   output: just the command's real output (the injected marker is stripped)

• Pass shell explicitly ('bash' or 'powershell'). shell:'auto' detects the shell from the terminal window, but it cannot see a shell running inside SSH or WSL — the window still looks like its local host — so for remote/nested sessions pass the remote side's shell (auto otherwise warns and may pick the outer shell). A window whose process is genuinely unidentifiable (e.g. Windows Terminal) returns ExitModeShellAmbiguous.
• First-class shells: bash and powershell. cmd.exe is not supported yet (ExitModeShellUnsupported).
• Unsafe input is rejected up front (ExitModeUnsafeInput) rather than hanging: a command ending mid-construct (unterminated quote, here-doc, $(…), a trailing \ or PowerShell backtick).
• Exit mode controls its own delivery, so delivery-shaping sendOptions (method / preferClipboard / pressEnter / chunkSize / pasteKey) are rejected with InvalidArgs; focus options remain accepted.

Browser CDP automation

For web automation, connect Chrome or Edge with the remote debugging port enabled — no Selenium or Playwright needed.

# Launch Chrome in CDP mode
chrome.exe --remote-debugging-port=9222 --user-data-dir=C:\tmp\cdp

browser_open({launch:{}})                          → spawn-if-needed Chrome in debug mode + list tabs (idempotent)
browser_open()                                     → connect-only (fail if no CDP endpoint live)
browser_locate({selector:"#submit"})               → CSS selector → physical screen coords
browser_click({selector:"#submit"})                → find + click in one step (auto-focuses browser)
browser_eval({action:"js", expression:"document.title"})  → evaluate JS, returns result
browser_eval({action:"dom", selector:"#main", maxLength:5000})  → outerHTML, truncated to maxLength chars
browser_eval({action:"appState"})                  → one-shot SPA state (Next/Nuxt/Remix/Apollo/GitHub react-app/Redux SSR)
browser_fill({selector:"#email", value:"user@example.com"})  → fill React/Vue/Svelte controlled input (state-safe)
browser_overview()                                 → links/buttons/inputs + ARIA toggles + viewportPosition per element
browser_search({by:"text", pattern:"..."})         → grep DOM with confidence ranking
browser_navigate({url:"https://example.com"})      → navigate via CDP (no address bar interaction)

For chained calls in the same tab, pass includeContext:false to omit the activeTab/readyState annotation (~150 tok/call saved). Boolean / object params accept the LLM-friendly string spellings ("true", "{}").

Coordinates returned by browser_locate account for the browser chrome (tab strip + address bar height) and devicePixelRatio, so they can be passed directly to mouse_click without any scaling.

Recommended web workflow:

browser_open({launch:{}}) → browser_eval({action:"dom"}) → browser_locate(selector) → browser_click(selector)

Auto-dock CLI on startup

Keep Claude CLI visible while operating other apps full-screen. Set env vars in your MCP config and the docked window auto-snaps into place every MCP startup.

{
  "mcpServers": {
    "desktop-touch": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "@harusame64/desktop-touch-mcp"],
      "env": {
        "DESKTOP_TOUCH_DOCK_TITLE": "@parent",
        "DESKTOP_TOUCH_DOCK_CORNER": "bottom-right",
        "DESKTOP_TOUCH_DOCK_WIDTH": "480",
        "DESKTOP_TOUCH_DOCK_HEIGHT": "360",
        "DESKTOP_TOUCH_DOCK_PIN": "true"
      }
    }
  }
}

Input routing gotcha: when a pinned window is active (e.g. Claude CLI), keyboard(action='type') / keyboard(action='press') send keys to it, not the app you wanted to type into. Always call focus_window(title=...) before keyboard operations, then verify isActive=true via screenshot(detail='meta').

Screenshot cache (by-ref storage)

screenshot and the other visual results return a cheap screenshot://by-ref/{id} link to an image saved on disk instead of inlining the pixels every time, so routine look-act-confirm loops cost far fewer tokens. The cache bounds itself automatically and screenshot_query / screenshot_gc let you inspect and prune it. Tune the storage with:

Auto Perception (always-on)

Phase 4 privatizes the explicit perception_* tool family — the v0.12 Auto Perception layer attaches an attention signal to every desktop_state and desktop_act response automatically. Action tools also auto-guard when given a windowTitle. There is no longer a need to register / read / forget lenses manually.

# desktop_state always returns the attention signal
desktop_state() → {focusedWindow, focusedElement, modal, attention:"ok", ...}

# Action tools auto-guard when windowTitle is given:
keyboard({action:"type", text:"hello", windowTitle:"Notepad"})
→ post.perception:{status:"ok"}  // unsafe input blocked if guards fail

# When attention is dirty / stale / settling, refresh with desktop_state:
desktop_state()  // re-evaluates attention via Auto Perception

For advanced pinned-target workflows, the lensId parameter remains on action tools (keyboard, mouse_click, mouse_drag, click_element, browser_click, browser_navigate, browser_eval, desktop_act). Omit lensId for the normal Auto Perception path. The underlying registry, hot target cache, and sensor loop are unchanged; only the explicit perception_register / perception_read / perception_forget / perception_list tools were retired.

Mouse homing correction

When Claude calls screenshot(detail='text') to read coordinates and then mouse_click seconds later, the target window may have moved. The homing system corrects this automatically.

# Tier 1 only (automatic)
mouse_click(x=500, y=300)

# Tier 1 + 2: also bring window to front if hidden
mouse_click(x=500, y=300, windowTitle="Notepad")

# Tier 1 + 2 + 3: also re-query UIA if window resized
mouse_click(x=500, y=300, windowTitle="Notepad", elementName="Save")

# Traction control OFF — no correction
mouse_click(x=500, y=300, homing=false)

The homing parameter is available on mouse_click, mouse_drag, and scroll. The cache is updated automatically on every screenshot(), desktop_discover(), focus_window(), and workspace_snapshot() call.

mouse_click image-local coords (origin + scale)

When you take a dotByDot screenshot with dotByDotMaxDimension, the response prints the origin and scale values. Instead of computing screen coords manually, copy them into mouse_click:

# Screenshot response:
#   origin: (0, 120) | scale: 0.6667
#   To click image pixel (ix, iy): mouse_click(x=ix, y=iy, origin={x:0, y:120}, scale=0.6667)

mouse_click(x=640, y=300, origin={x:0, y:120}, scale=0.6667, windowTitle="Chrome")
# Server converts: screen = (0 + 640/0.6667, 120 + 300/0.6667) = (960, 570)

This eliminates a whole class of off-by-one and scale bugs. Without origin/scale, x/y remain absolute screen pixels (unchanged behavior).

screenshot key parameters

detail="image"          — PNG/WebP pixels (default)
detail="text"           — UIA element JSON + clickAt coords (no image, ~100–300 tok)
detail="meta"           — Title + region only (cheapest, ~20 tok/window)
dotByDot=true           — 1:1 WebP; image_px + origin = screen_px
dotByDotMaxDimension=N  — cap longest edge (response includes scale for coord math)
grayscale=true          — ~50% smaller for text-heavy captures (code/AWS console)
region={x,y,w,h}        — with windowTitle: window-local coords (exclude browser chrome)
                          without: virtual screen coords
diffMode=true           — I-frame first call, P-frame (changed windows only) after (~160 tok)
ocrFallback="auto"      — detail='text' auto-fires Windows OCR on uiaSparse or empty

Recommended Chrome combo (50–70% data reduction):

screenshot(windowTitle="Chrome",
           dotByDot=true, dotByDotMaxDimension=1280, grayscale=true,
           region={x:0, y:120, width:1920, height:900})  # skip browser chrome

Recommended workflow:

workspace_snapshot()                     → full orientation (resets diff buffer)
screenshot(detail="text", windowTitle=X) → get actionable[].clickAt coords
mouse_click(x, y)                        → click directly, no math needed
screenshot(diffMode=true)                → check only what changed (~160 tok)

Security

Emergency stop (Failsafe)

Move the mouse to the top-left corner of the screen (within 10px of 0,0) to immediately terminate the MCP server.

• Per-tool check: checkFailsafe() runs before every tool handler
• Background monitor: 500ms polling as a backup for long-running operations
• Trigger radius: 10px

Blocked operations

workspace_launch blocklist: cmd.exe, powershell.exe, pwsh.exe, wscript.exe, cscript.exe, mshta.exe, regsvr32.exe, rundll32.exe, msiexec.exe, bash.exe, wsl.exe are blocked. Script extensions (.bat, .ps1, .vbs, etc.) are rejected. Arguments containing ;, &, |, `, $(, ${ are also rejected.

keyboard(action='press') blocklist: Win+R (Run dialog), Win+X (admin menu), Win+S (search), Win+L (lock screen) are blocked.

PowerShell injection protection

All -like patterns in the UIA bridge PowerShell fallback path are sanitized with escapeLike(), which escapes wildcard characters (*, ?, [, ]) before they reach PowerShell. When the Rust native engine is active, PowerShell is not invoked for UIA operations.

Allowlist for workspace_launch

Shell interpreters are blocked by default. To allow specific executables, create an allowlist file:

File locations (searched in order):

1. Path in DESKTOP_TOUCH_ALLOWLIST environment variable
2. ~/.claude/desktop-touch-allowlist.json
3. desktop-touch-allowlist.json in the server's working directory

Format:

{
  "allowedExecutables": [
    "pwsh.exe",
    "C:\\Tools\\myapp.exe"
  ]
}

Changes take effect immediately — no restart needed.

Mouse movement speed

All mouse tools (mouse_click, mouse_drag, scroll) accept an optional speed parameter:

Default speed is 1500 px/sec. Change it permanently via the DESKTOP_TOUCH_MOUSE_SPEED environment variable:

{
  "mcpServers": {
    "desktop-touch": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "@harusame64/desktop-touch-mcp"],
      "env": {
        "DESKTOP_TOUCH_MOUSE_SPEED": "3000"
      }
    }
  }
}

Common values: 0 = teleport, 1500 = default gentle, 3000 = fast, 5000 = very fast.

Force-Focus (AttachThreadInput)

Windows foreground-stealing protection can prevent SetForegroundWindow from succeeding when another window (such as a pinned Claude CLI) is in the foreground. This causes subsequent keystrokes or clicks to land in the wrong window — a silent failure.

mouse_click, keyboard(action='type'), keyboard(action='press'), and terminal(action='send') all accept a forceFocus parameter that bypasses this protection using AttachThreadInput:

{
  "name": "mouse_click",
  "arguments": {
    "x": 500,
    "y": 300,
    "windowTitle": "Google Chrome",
    "forceFocus": true
  }
}

If the force attempt is refused despite AttachThreadInput, the response is ok:false with code: "ForegroundRestricted" (issue #202 unification — same shape as focus_window, keyboard, terminal_send, mouse_click). The action itself is suppressed so the keystrokes / click never land on the wrong window. Recover via focus_window's auto-escalate ladder before retrying. The legacy hints.warnings: ["ForceFocusRefused"] shape is no longer emitted.

Global default via environment variable:

{
  "mcpServers": {
    "desktop-touch": {
      "env": {
        "DESKTOP_TOUCH_FORCE_FOCUS": "1"
      }
    }
  }
}

Setting DESKTOP_TOUCH_FORCE_FOCUS=1 makes forceFocus: true the default for all four tools without changing each call.

Known tradeoffs:

• During the ~10ms AttachThreadInput window, key state and mouse capture are shared between the two threads. In rapid macro sequences this can cause a race condition (rare in practice).
• Disable forceFocus (or unset the env var) when the user is manually operating another app to avoid unexpected focus shifts.

Auto Guard

Action tools (mouse_click, mouse_drag, keyboard(action='type'/'press'), click_element, desktop_act, browser_click, browser_navigate) automatically guard each action when you pass windowTitle / tabId:

• Verifies target window identity (process restart / HWND replacement detected)
• Confirms click coordinates are inside the target window rect
• Returns post.perception.status on every response — including failures — so the LLM can recover without a screenshot

Disabling auto guard — set DESKTOP_TOUCH_AUTO_GUARD=0 to restore v0.11.12 behavior (no auto guard):

{
  "mcpServers": {
    "desktop-touch": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "@harusame64/desktop-touch-mcp"],
      "env": {
        "DESKTOP_TOUCH_AUTO_GUARD": "0"
      }
    }
  }
}

When auto guard is enabled (default), post.perception.status will be one of:

When unsafe_coordinates or identity_changed is returned, the response may include a suggestedFix.fixId. Pass that fixId to the relevant tool call to approve the recovery:

{ "name": "mouse_click",           "arguments": { "fixId": "fix-..." } }
{ "name": "keyboard(action='type')",         "arguments": { "fixId": "fix-...", "text": "hello" } }
{ "name": "click_element",         "arguments": { "fixId": "fix-..." } }
{ "name": "browser_click", "arguments": { "fixId": "fix-..." } }

The fix is one-shot and expires in 15 seconds. The server revalidates the target process identity before executing.

Advanced response options

browser_eval Structured Mode

Pass withPerception: true to receive a structured JSON response with post.perception instead of raw text:

{ "name": "browser_eval", "arguments": { "expression": "document.title", "withPerception": true } }

Returns { ok: true, result: "...", post: { perception: { status: "ok", ... } } }.

mouse_drag Cross-Window Guard

mouse_drag now guards both start and end coordinates. Drags that cross window boundaries (or reach the desktop wallpaper) are blocked by default. To allow intentional cross-window or range-selection drags:

{ "name": "mouse_drag", "arguments": { "startX": 100, "startY": 100, "endX": 900, "endY": 900, "allowCrossWindowDrag": true } }

Performance (v0.15 — Rust Native Engine)

The Rust native engine (@harusame64/desktop-touch-engine) replaces PowerShell process spawning with direct COM calls over a persistent MTA thread. It loads automatically as a .node addon — no configuration needed.

UIA Benchmark (vs PowerShell baseline)

Image Diff Benchmark (SSE2 SIMD)

Architecture

Claude CLI / MCP Client
    │  stdio or HTTP (MCP protocol)
    ▼
desktop-touch-mcp (TypeScript)
    │
    ├── Rust Native Engine (.node addon)          ← NEW in v0.15
    │   ├── UIA: 13 functions via napi-rs + windows-rs 0.62
    │   │   └── Dedicated COM thread (MTA) + batch BFS algorithm
    │   └── Image: SSE2 SIMD pixel diff + perceptual hashing
    │
    └── PowerShell Fallback (automatic)
        └── Activates transparently if .node is unavailable

Why getUiElements is 3.3× (not 160×)

The 160× speedup on getFocusedElement comes from eliminating PowerShell process startup (~200 ms) and .NET assembly loading. For getUiElements, the bottleneck shifts to the UIA provider inside the target application (e.g., Explorer) — it must enumerate its UI tree regardless of who asks. The Rust engine uses a batch BFS algorithm (FindAllBuildCache + TreeScope_Children) that minimizes cross-process RPC calls and supports maxElements early exit, making it dramatically faster on large trees (VS Code, browsers with 1000+ elements).

UI Operating Layer (V2)

Status: Default ON since v0.17. desktop_discover and desktop_act are available out of the box.

V2 introduces two new tools that replace coordinate-based clicking with entity-based interaction:

Clicking — priority order

When multiple tools could perform the same click, prefer them in this order:

1. browser_click(selector) — Chrome / Edge over CDP (stable across repaints)
2. desktop_act(lease) — native windows, dialogs, visual-only targets (entity-based; use after desktop_discover)
3. click_element(name | automationId) — native UIA fallback when desktop_act returns ok:false
4. mouse_click(x, y) — pixel-level last resort (origin + scale from dotByDot screenshots only)

Disabling V2 (kill switch)

To hide desktop_discover / desktop_act from the tool catalog, add the disable flag and restart:

{
  "mcpServers": {
    "desktop-touch": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "@harusame64/desktop-touch-mcp"],
      "env": {
        "DESKTOP_TOUCH_DISABLE_FUKUWARAI_V2": "1"
      }
    }
  }
}

All V1 tools continue to work without interruption — no reinstall required. Remove the env entry and restart to re-enable.

Flag semantics (exact-match: only the literal string "1" counts):

Removed: DESKTOP_TOUCH_ENABLE_FUKUWARAI_V2

This was the opt-in switch in v0.16.x. V2 is on by default since v0.17, so the flag no longer has any effect and is safe to delete from your config. To turn V2 off, set DESKTOP_TOUCH_DISABLE_FUKUWARAI_V2=1.

Recovery when V2 fails

If desktop_act returns ok: false, read reason and follow the built-in recovery hints in the tool description. Common paths:

• lease_expired / *_mismatch / entity_not_found → re-call desktop_discover
• modal_blocking → response.blockingElement (when present) carries { name, role, automationId? }; dismiss with click_element(name=blockingElement.name), then retry
• entity_outside_viewport → scroll / scroll(action='to_element'), then re-call desktop_discover
• executor_failed → fall back to click_element / mouse_click / browser_click

For desktop_discover warnings (visual_provider_unavailable, visual_provider_warming, cdp_provider_failed, …), the coordinate-based tools (screenshot(detail='text'), click_element, mouse_click, terminal, …) remain available as an escape hatch.

Known limitations

Token cost reference

🚀 3,000+ Downloads!

This project just passed 3,000+ downloads. Huge thanks to everyone who tried an experimental desktop-automation MCP server, filed issues, opened PRs, and shared what broke. Every bug report made the next release better. Thank you for building with me!

License

MIT