screenshot
Capture desktop windows or regions with configurable detail: window titles, UIA elements, OCR text, or pixel-accurate screenshots in normal or background mode.
Instructions
Purpose: Capture desktop, window, or region across detail levels (meta / text / image / som / ocr) and capture modes (normal / background). Details: detail='meta' (default) returns window titles+positions only (~20 tok/window, no image). detail='text' returns UIA actionable elements with clickAt coords, no image (~100-300 tok). detail='som' returns a Set-of-Marks annotated image plus OCR-detected elements with IDs (bypasses UIA entirely). detail='ocr' returns Windows OCR words with screen-pixel clickAt coords (Phase 4: absorbs former screenshot_ocr — use when UIA is sparse and you want to force OCR unconditionally). detail='image' and detail='som' are server-blocked unless confirmImage=true is also passed. mode='background' captures hidden/minimised/occluded windows via PrintWindow (Phase 4: absorbs former screenshot_background) — pair with windowTitle/hwnd. dotByDot=true returns 1:1 pixel WebP; compute screen coords: screen_x = origin_x + image_x (or screen_x = origin_x + image_x / scale when dotByDotMaxDimension is set — scale printed in response). diffMode=true returns only changed windows after the first call (~160 tok). region={x,y,width,height} captures a sub-rectangle (Phase 4: absorbs former scope_element when paired with windowTitle/hwnd — discover element bounds via desktop_discover, then pass region here). Data reduction: grayscale=true (−50%), dotByDotMaxDimension=1280 (caps longest edge), windowTitle+region (sub-crop to exclude browser chrome — e.g. region={x:0, y:120, width:1920, height:900}). Prefer: Use meta to orient, text before clicking, dotByDot only when precise pixel coords are needed. Use detail='som' for native apps or games that do not expose UIA elements (UIA-Blind). Use detail='ocr' for OCR-only (skip UIA entirely). Use mode='background' when the target window must stay hidden or cannot be brought to foreground. Prefer browser_* tools for Chrome. Use diffMode after actions to confirm state changed. Only use image+confirmImage when text returned 0 actionable elements and visual inspection is genuinely required. Caveats: Default mode scales to maxDimension=768 — image pixels ≠ screen pixels; apply the scale formula before passing to mouse_click. Foreground detail='image' is always blocked without confirmImage=true. diffMode requires a prior full-capture baseline (non-diff call or workspace_snapshot) — calling diffMode cold returns a full frame, not a diff. mode='background' requires windowTitle or hwnd, and only composes with detail in {'image','meta'} — detail='text'/'som'/'ocr' run only against foreground capture (the dispatcher rejects the conflicting combination). Passing mode='background' is itself the acknowledgement that image pixels are wanted, so confirmImage is NOT required for it (matches the former screenshot_background contract). fullContent=false enables legacy mode (faster but GPU windows may be black). detail='ocr' requires windowTitle or hwnd; first call may take ~1s (WinRT cold-start) and the matching OCR language pack must be installed. Examples: screenshot() → meta orientation of all windows screenshot({detail:'text', windowTitle:'Notepad'}) → clickable elements with coords screenshot({detail:'ocr', windowTitle:'PDF', ocrLanguage:'ja'}) → OCR words with screen-pixel coords screenshot({mode:'background', windowTitle:'Chrome', dotByDot:true, dotByDotMaxDimension:1280, grayscale:true}) → background-capture pixel-accurate Chrome screenshot({windowTitle:'Notepad', region:{x:0,y:120,width:600,height:400}}) → cropped sub-region (zoom into element after desktop_discover)
Input Schema
| Name | Required | Description | Default |
|---|---|---|---|
| windowTitle | No | Capture only the window whose title contains this string. Use '@active' for the current foreground window. Prefer over full-screen when target window is known. | |
| hwnd | No | Direct window handle ID (takes precedence over windowTitle). Obtain from desktop_discover (windows[].hwnd). String type to avoid 64-bit precision issues. | |
| displayId | No | Capture a specific monitor (0 = primary). Use desktop_state({includeScreen:true}) to list displays. | |
| region | No | Capture only this sub-region. Without windowTitle: virtual screen coordinates. With windowTitle: window-local coordinates — useful to exclude browser chrome (tabs/address bar). Example: windowTitle='Chrome', region={x:0, y:120, width:1920, height:900} skips the 120px browser chrome. | |
| maxDimension | No | Max width or height in pixels (default 768). Use 1280 to read small text, code, or fine UI details. Ignored when dotByDot=true. | |
| dotByDot | No | 1:1 pixel mode — no scaling, WebP compression. Window captures include 'origin: (x,y)' so you can compute screen position: screen_x = origin_x + image_x. When dotByDotMaxDimension is also set, scale factor is included: screen_x = origin_x + image_x / scale. | |
| dotByDotMaxDimension | No | Cap the longest edge (pixels) when dotByDot=true. Reduces payload while preserving coordinate math. Example: 1280 on a 1920×1080 screen → scale≈0.667. Response includes scale factor: screen_x = origin_x + image_x / scale. Recommended for Chrome: dotByDot=true, dotByDotMaxDimension=1280, grayscale=true. | |
| grayscale | No | Convert to grayscale before encoding. Reduces file size ~50% for text-heavy content (e.g. AWS console, code editors). Avoid when color is meaningful (charts, status indicators). | |
| webpQuality | No | WebP quality when dotByDot=true or diffMode=true. 40=layout only, 60=general (default), 80=fine text. | |
| diffMode | No | Layer diff mode — compares each window against the buffered previous frame. First call = full I-frame (all windows). Subsequent calls = only changed windows (P-frame). Implicitly enables dotByDot. Best used with windowTitle=undefined to snapshot all windows. | |
| detail | No | Response detail level (omit to let the server pick a smart default): omitted — auto: 'image' when dotByDot/region/displayId is specified, else 'meta' 'meta' — window title + screen region only (~20 tok/window, cheapest) 'text' — UIA element tree as JSON with text values (~100-300 tok/window, no image) 'image' — actual screenshot pixels. BLOCKED unless confirmImage=true is also passed. 'som' — Set-of-Marks image + OCR elements (bypasses UIA entirely). BLOCKED unless confirmImage=true is also passed. 'ocr' — Windows OCR words with screen-pixel clickAt coords (Phase 4: absorbs former screenshot_ocr). Use when UIA returns no actionable elements (WinUI3 custom-drawn UIs, game overlays, PDF viewers). Note: detail='text' auto-falls back to OCR via ocrFallback='auto'; choose detail='ocr' only when forcing OCR unconditionally. | |
| mode | No | Capture mode. 'normal' — default. Window-targeted captures (windowTitle / hwnd) use Win32 PrintWindow with automatic BitBlt fallback when PrintWindow returns no data or an all-black frame; the route used is reported in hints.captureSource. Fullscreen / displayId captures use BitBlt. 'background' — explicit Win32 PrintWindow capture, retained for back-compat and explicit selection. Requires windowTitle (or hwnd). Pair with fullContent for GPU-rendered apps. | normal |
| fullContent | No | When mode='background', use PW_RENDERFULLCONTENT to capture GPU-rendered windows (Chrome, Electron, WinUI3). Default true. Set false for legacy mode (faster but GPU windows may appear black). Ignored unless mode='background'. | |
| confirmImage | No | Must be true to receive image pixels when detail='image'. Without this flag, detail='image' is blocked and a guidance message is returned instead. Prefer detail='text' / diffMode=true / dotByDot=true first — only set confirmImage=true when visual inspection is genuinely required. | |
| ocrFallback | No | OCR fallback behaviour when detail='text'. 'auto' (default): fire Windows OCR if UIA returns 0 actionable elements OR hints.uiaSparse=true (UIA returned <5 elements, typical for Chrome). 'always': always augment actionable[] with OCR words. 'never': disable OCR entirely. | auto |
| ocrLanguage | No | BCP-47 language tag for the OCR engine (e.g. 'ja', 'en-US'). Used when detail='text' (OCR fallback) or detail='ocr' (direct OCR). | ja |
| preprocessPolicy | No | OCR preprocessing scale policy for detail='som' and OCR fallback paths. 'auto' (default): clamp scale to 1 on OOM (>8MP) or high-DPI (≥150%). 'aggressive': relaxes DPI clamp to 175%, preserving upscale on 150%-DPI monitors (e.g. Outlook PWA). Also auto-enables adaptive binarization. 'minimal': always scale=1 regardless of DPI/resolution. | auto |
| preprocessAdaptive | No | When true, apply Sauvola adaptive binarization after contrast stretch. Improves recognition of thin text on low-contrast or gradient backgrounds. Automatically enabled when preprocessPolicy='aggressive'. Requires Rust native engine; silently skipped otherwise. | |
| include | No | Optional response-shape opt-in. `['envelope']` returns the self-documenting envelope (`_version` / `data` / `as_of` / `confidence`). `['raw']` forces raw shape (overrides DESKTOP_TOUCH_ENVELOPE=1 server default). Default behaviour is raw shape (compat with existing clients). |