Screenshot

Capture, inspect, and compare screenshots of screens, windows, regions, web pages, simulators, and CI runs with the right tool, wait strategy, viewport, and...

Security Scan

This is an instruction-only screenshot best-practices guide; it requests no credentials, has no install step, and its guidance is aligned with its stated purpose.

Purpose & Capability

The name/description claim a screenshot-capture guide and the SKILL.md contains only guidance about choosing capture tools, stabilization, masking, formats, and CI practices. It does not request unrelated permissions, binaries, or cloud credentials.

Instruction Scope

Instructions focus on capturing and validating screenshots (tool selection, waiting strategies, masking, output formats). They do not instruct reading unrelated system files, exfiltrating data, or contacting external endpoints. The guidance to mask secrets is a positive privacy consideration.

Install Mechanism

There is no install spec and no code files — the skill is purely documentation/instructional, so nothing is written to disk or downloaded by the skill itself.

Credentials

The skill declares no required environment variables, credentials, or config paths. Tool recommendations (Playwright, screencapture, grim, etc.) are reasonable for the documented use cases and are not requested as required by the skill.

Persistence & Privilege

always is false and the skill does not request persistent privileges or modify other skills. It can be invoked autonomously (the platform default), but that is normal and not accompanied by other concerning privileges.

Assessment

This skill is a safe, read-only set of instructions for taking reliable screenshots. Before you run any commands the agent suggests: (1) confirm the specific capture tool is installed on your machine (Playwright requires Node and browser installs), (2) allow screen-capture permissions only if you trust the agent/host, and (3) follow the guidance to mask or avoid capturing any secrets or personal data. Because it is instruction-only, the registry scan had nothing to analyze — that is expected, not an indication of hidden code. If you want the agent to actually run capture commands, review the exact commands first so you know which local binaries will be invoked.

When to Use

Use when the task needs a screenshot of a desktop app, browser page, simulator, region, window, or full screen, especially for debugging, QA, documentation, release notes, bug reports, visual review, or before/after comparison.

This skill is about taking the right screenshot reliably, not about editing images after the fact.

Tool Choice

Context	Best default	Why
macOS desktop or window	screencapture	Built-in, reliable, supports silent, interactive, region, and window capture
iOS Simulator	xcrun simctl io booted screenshot	More reliable than generic desktop capture for simulator output
Linux Wayland	grim + slurp	X11 tools often fail or behave oddly on Wayland
Linux X11 / headless CI	scrot or browser-native capture	Works in minimal or virtual-display environments
Windows desktop capture	nircmd savescreenshot or Pillow ImageGrab	Easier than verbose PowerShell screen APIs
Web page or web app	Playwright	Best for stable viewport, element, full-page, masked, and regression screenshots
Visual diff / screenshot tests	Playwright with fixed viewport	Better control over animations, caret, masks, and reproducibility

Default to the most native capture path first. Move to browser-native tooling when determinism, masking, element capture, or visual regression matters more than convenience.

Core Rules

1. Pick the capture path by artifact, not by habit

• Desktop UI screenshots usually want OS-native tools.
• Web pages and web apps usually want browser-native capture, not a desktop screenshot of the browser window.
• Simulator screenshots should come from the simulator tooling when possible.
• Use region, window, or element capture when the point is local; use full screen or full page only when the full context matters.

2. Stabilize the target before capturing

• Dynamic pages should settle before capture: wait for network idle or the specific element that matters, then give fonts and transitions a brief moment to finish.
• Do not take the screenshot before the real rendered state exists.
• For browser capture, prefer explicit readiness over blind sleeps when possible.
• If the page never truly goes idle, wait for the exact UI state you need instead of chasing perfect stillness.

3. Freeze viewport, scale, zoom, and theme for reproducibility

• Screenshot comparisons are meaningless if viewport, zoom level, theme, or device scale changed.
• For browser captures, fix the viewport before taking baselines or before/after images.
• Retina and HiDPI displays can produce more pixels than expected; decide whether you want physical pixels or CSS-scale output and keep that choice consistent.
• If dark/light mode matters, capture both intentionally instead of mixing them accidentally.

4. Capture the smallest useful scope

• Element, region, or window screenshots are usually better than noisy full-screen captures.
• Full-page screenshots are useful for audits and archives, but long pages become hard to read and compare.
• For browser work, element screenshots or clipped regions usually produce cleaner diffs than full-page output.
• If the screenshot is evidence, keep enough surrounding context that the user can understand what they are looking at.

5. Remove noise before you capture

• Hide or avoid unstable UI when it is not the subject: cursors, carets, toasts, chat widgets, notifications, loading spinners, timestamps, and randomized content.
• Mask or avoid secrets, personal data, tokens, and internal URLs before capture.
• For Playwright-style browser capture, features like disabled animations, hidden carets, and masking are worth using when visual stability matters.
• If the noise is the bug, keep it; otherwise remove it.

6. Use the right output format

• PNG is the default for screenshots, UI, code, terminals, and text-heavy captures.
• JPEG is for photographic content, not normal screenshots.
• WebP is fine for sharing or storage when compatibility is acceptable, but do not default to it if the consumer expects plain PNG files.
• Avoid recompressing screenshots through JPEG pipelines unless the user explicitly wants smaller lossy output.

7. Make automation and CI captures debuggable

• On failures, save a screenshot immediately before retrying or moving on.
• Use stable filenames for baselines and timestamps for ad hoc or batch captures.
• In CI, identical viewport and deterministic state matter more than raw screenshot volume.
• Headless runs should prefer browser-native screenshots over trying to screen-grab the host display.

8. Validate that the screenshot is actually useful

• Check that the important detail is visible, legible, and not cropped away.
• Verify that secrets are not still visible in tabs, sidebars, URLs, notifications, or test data.
• Before/after comparisons should use the same viewport, zoom, theme, and state.
• A screenshot is bad if it is technically correct but useless for the human who needs it.

High-Value Patterns

• macOS: screencapture -x out.png for silent capture, -i for interactive selection, -R x,y,w,h for a fixed region.
• iOS Simulator: xcrun simctl io booted screenshot out.png
• Linux Wayland: grim -g "$(slurp)" out.png
• Playwright page capture: wait for the target state, then use page, element, clipped, or full-page screenshots deliberately.
• Playwright stability features worth remembering: fixed viewport, disabled animations, hidden caret, masks for sensitive regions, and stable theme/media settings.

Common Traps

• Taking a browser-window screenshot when an element or page screenshot was the real need.
• Capturing before fonts, data, or layout transitions finish.
• Comparing screenshots with different viewport sizes or zoom levels and treating the diff as meaningful.
• Using JPEG for screenshots and blurring text, edges, and code.
• Letting timestamps, cursor blinks, notifications, or random data ruin visual diffs.
• Forgetting that Wayland breaks familiar X11 screenshot tools.
• Sharing screenshots with secrets still visible in tabs, sidebars, URLs, or test accounts.
• Taking full-page captures of huge pages and ending up with unreadable evidence.

Related Skills

Install with clawhub install <slug> if user confirms:

• playwright — Browser automation, DOM interaction, and web screenshots
• image — Post-capture format, cropping, compression, and export decisions
• image-edit — Annotation, cleanup, masking, and targeted edits after capture
• documentation — Turning screenshots into docs, guides, and release assets
• video — When a flow should be recorded instead of reduced to still images

Feedback

• If useful: clawhub star screenshot
• Stay updated: clawhub sync