MCP 服务器

MCP ScreenCatch

Enables Claude Desktop to capture screenshots through an interactive region selection interface, automatically saving timestamped images to a configurable directory for analysis and documentation.

README

MCP ScreenCatch

An MCP (Model Context Protocol) server that provides screen capture functionality for Claude Desktop, emulating Windows Snipping Tool capabilities.

Overview

MCP ScreenCatch enables Claude Desktop to capture screenshots of user-selected screen regions. The tool allows users to highlight areas of their monitor(s), capture them, and save the images with timestamps for easy retrieval and processing.

Objectives

Seamless Integration: Provide an MCP command that Claude Desktop can invoke to initiate screen captures
Interactive Selection: Allow users to select specific regions of their screen(s) using a familiar snipping interface
Multi-Monitor Support: Work across multiple monitors for flexible screen capture
Sequential Captures: Enable users to capture multiple screenshots in succession without restarting the tool
Timestamped Files: Automatically timestamp each capture for chronological ordering
Configurable Output: Let users specify the output directory for captured images
Pipeline Ready: Save files in a location accessible to other MCP commands or external applications

Features

Core Functionality

Region Selection: Click and drag interface to select screen regions
Capture & Save: Button/icon to finalize and save the selected region
Continuous Mode: After each capture, prompt user to:
- Capture another screenshot
- Quit the tool
Timestamp Naming: Files named with ISO 8601 timestamps (e.g., capture_2025-11-27_064730.png)
Directory Selection: User-configurable output directory

Use Cases

Capture UI elements for debugging
Document visual workflows
Create sequential tutorials or guides
Feed captured images to Claude for analysis
Build visual documentation pipelines

Technical Implementation

MCP Protocol

The tool will be exposed as an MCP server that Claude Desktop can connect to, providing:

Tool: capture_screen - Initiates the screen capture interface
Tool: set_output_directory - Configure where captures are saved
Tool: list_captures - Retrieve timestamped capture files

Technology Stack

Language: TypeScript/Node.js
MCP SDK: @modelcontextprotocol/sdk
Screen Capture: screenshot-desktop for cross-platform screen capture
Image Processing: Sharp for image cropping and manipulation
UI Framework: Electron for transparent overlay and region selection

File Format

Default format: PNG (lossless, good for UI captures)
Naming convention: capture_YYYY-MM-DD_HHMMSS.png
Metadata: Optional JSON sidecar with capture timestamp and dimensions

Installation

npm install
npm run build

Configuration

Add to Claude Desktop config (claude_desktop_config.json):

{
  "mcpServers": {
    "screencatch": {
      "command": "node",
      "args": ["/path/to/mcp-screencatch/build/index.js"]
    }
  }
}

Usage

From Claude Desktop

Once configured, you can ask Claude to capture screenshots:

Claude, can you capture a screenshot of my screen?

Interactive Overlay

An Electron overlay window will appear covering your screen(s)
Click and drag to select the region you want to capture
Click the Capture button or press Enter to save
Press ESC or click Cancel to abort
The captured image is saved with a timestamp

Available Commands

Capture a screenshot:

Claude, capture a screenshot

Set output directory:

Claude, set the screenshot output directory to C:\Users\johne\screenshots

List recent captures:

Claude, list my recent screenshots

File Naming

Screenshots are automatically named with ISO 8601 timestamps:

capture_2025-11-27_143052.png
capture_2025-11-27_143105.png

This ensures chronological ordering and prevents filename conflicts.

Development Status

✅ Implemented - Core functionality complete

✅ MCP server with stdio transport
✅ Interactive region selection with Electron overlay
✅ Timestamped file naming
✅ Configurable output directory
✅ List and manage captures
⚠️ Note: Requires Electron, which adds ~150MB to node_modules. For production use, consider electron-builder for packaging.