Taking and Analyzing Screenshots

Overview

You CAN take screenshots by combining the Bash tool with platform-specific screenshot commands. Screenshots are saved as image files, then loaded into your context using the Read tool for visual analysis.

When to Use

Use this skill when I ask you to:

• "Take a screenshot"
• "Look at my screen"
• "Analyze this UI bug visually"
• "Review what's currently displayed"
• "Capture and examine the interface"

Quick Reference

| Platform | Command | Interactive Selection | | -------- | ---------------------------------------- | -------------------------- | | macOS | screencapture | -i flag (area selection) | | Linux | gnome-screenshot, scrot, or import | -a or -s flag |

Standard workflow:

1. Detect platform with uname -s
2. Check for available screenshot tool
3. Capture to /tmp/screenshot_$(date +%s).png
4. Use Read tool with the file path
5. Analyze the image
6. Optionally clean up temp file

Step-by-Step Instructions

1. Detect Platform

bash
uname -s

• Returns Darwin for macOS
• Returns Linux for Linux

2. Check Available Tools

macOS: screencapture is always available (built-in)

Linux: Check in priority order:

bash
which gnome-screenshot || which scrot || which import || echo "none"

Priority order (best compatibility):

1. gnome-screenshot - works on both X11 and Wayland
2. scrot - lightweight, X11 only
3. import - part of ImageMagick

3. Capture Screenshot

Use timestamped filename to avoid conflicts:

macOS:

bash
screencapture -i /tmp/screenshot_$(date +%s).png

• -i enables interactive area selection
• User clicks and drags to select region

Linux with gnome-screenshot:

bash
gnome-screenshot -af /tmp/screenshot_$(date +%s).png

• -a for area selection
• -f specifies filename

Linux with scrot:

bash
scrot -s /tmp/screenshot_$(date +%s).png

• -s enables selection mode

Linux with import:

bash
import /tmp/screenshot_$(date +%s).png

• Provides crosshair for click-and-drag selection

4. Load Image into Context

bash
Read tool: file_path="/tmp/screenshot_12345.png"

The Read tool displays images visually. You'll see the screenshot and can analyze it.

5. Analyze the Image

Once loaded, you can:

• Identify UI elements
• Spot visual bugs
• Review design elements
• Read text content
• Examine layout issues

6. Optional Cleanup

bash
rm /tmp/screenshot_12345.png

Only remove if I won't need the file again.

Handling Missing Tools

If no screenshot tool is available on Linux:

1. Inform me which tool is missing
2. Suggest installation:

• Ubuntu/Debian: sudo apt install gnome-screenshot
• Fedora: sudo dnf install gnome-screenshot
• Arch: sudo pacman -S gnome-screenshot
• ImageMagick: sudo apt install imagemagick (or equivalent)

1. Alternative: Ask user to manually take screenshot and provide path

Common Mistakes

❌ Saying "I cannot take screenshots"

Reality: You CAN via Bash + screenshot CLI tools

❌ Forgetting to use Read tool after capture

Reality: The screenshot file must be loaded with Read tool to see it

❌ Using relative paths

Reality: Always use absolute paths (/tmp/...) for Read tool

❌ Not checking for available tools on Linux

Reality: Must detect which tool is installed before attempting capture

Example Workflow

User: "Take a screenshot and help me debug this UI bug"

1. Check platform:
   uname -s → Linux

2. Check available tools:
   which gnome-screenshot → /usr/bin/gnome-screenshot

3. Capture screenshot:
   gnome-screenshot -af /tmp/screenshot_1729012345.png
   → User selects area, file saved

4. Load into context:
   Read: file_path="/tmp/screenshot_1729012345.png"
   → Image displays visually

5. Analyze:
   "I can see the button alignment is off. The 'Submit' button
   is 5px lower than the 'Cancel' button..."

6. Optional cleanup:
   rm /tmp/screenshot_1729012345.png