MCPgee
MCPgee
MCPgeeMCPgee

WelsonJS

v1.0.0•Developer Tools•stable

WelsonJS - Build a Windows app on the Windows built-in JavaScript engine

agiautomationchatgptchromecopilot
Share:
451
Stars
0
Downloads
0
Weekly
0/5
View on GitHub

What is WelsonJS?

WelsonJS is a Model Context Protocol (MCP) server that allows AI assistants like Claude, Cursor, and VS Code to welsonjs - build a windows app on the windows built-in javascript engine

WelsonJS - Build a Windows app on the Windows built-in JavaScript engine

This server falls under the Developer Tools category on MCPgee, the world's largest MCP server directory with 33,000+ servers.

Features

  • WelsonJS - Build a Windows app on the Windows built-in JavaS

Use Cases

Windows desktop app development
JavaScript engine integration
Automation scripting
gnh1201

Maintainer

LicenseGPL-3.0
Languagejavascript
Versionv1.0.0
UpdatedMay 19, 2026
Statushealthy
Maintenanceactive

Works with

ClaudeOpenAIwindowsmacoslinux
View SourceBrowse All Servers

Installation

Manual Installation

npx welsonjs

Configuration

Configuration Details

Config File

claude_desktop_config.json

Performance

Response Metrics

Response Time< 200ms
ThroughputMedium

Resource Usage

Memory UsageLow
CPU UsageLow

How to Set Up and Use WelsonJS

WelsonJS is a Windows application framework and MCP server that leverages the Windows built-in ECMAScript (JScript) engine, enabling developers to build desktop apps, automation scripts, and AI integrations without installing any additional runtime. It supports TypeScript, CoffeeScript, and modern JavaScript transpiled to ES5, and includes integrations for Microsoft Office automation, Chrome DevTools Protocol, Android Debug Bridge, and AI services like ChatGPT and Gemini. Through its MCP server interface, Claude and other AI assistants can interact with Windows desktop environments, run scripts, and orchestrate local automation tasks.

Prerequisites

  • Windows XP SP3 or later (Windows 10/11 recommended; no additional runtime installation required)
  • WelsonJS Launcher downloaded from the project's Azure Blob Storage or GitHub releases
  • PowerShell 5+ for the automated bootstrap script (optional but recommended)
  • An MCP-compatible client such as Claude Desktop
  • Optional: Android Debug Bridge (adb) for ADB-based device automation features
1

Install WelsonJS via the bootstrap script

Run the PowerShell bootstrap script to download and configure WelsonJS automatically. This is the fastest setup path on Windows 10/11.

irm https://catswords.blob.core.windows.net/welsonjs/bootstrap.ps1 | iex
2

Verify the installation

Test the runtime by running the app.js entry point with the Windows Script Host. A help message or default output confirms the engine is working.

cscript app.js
3

Explore available modules

Browse the lib/ directory to discover built-in modules for HTTP, Office automation, cryptography, and AI integrations. Each module is a plain JS file importable via require().

dir lib\
4

Start the MCP server

Launch WelsonJS in MCP server mode to allow AI clients to connect and invoke Windows automation capabilities. Refer to the project wiki for the exact MCP server command.

cscript app.js mcp-server
5

Configure your MCP client

Add WelsonJS to Claude Desktop's MCP server configuration pointing at the cscript command and your WelsonJS installation path.

WelsonJS Examples

Client configuration

Claude Desktop configuration to connect to the WelsonJS MCP server running via Windows Script Host.

{
  "mcpServers": {
    "welsonjs": {
      "command": "cscript",
      "args": ["C:\\welsonjs\\app.js", "mcp-server"]
    }
  }
}

Prompts to try

Example prompts for Windows desktop automation via WelsonJS.

- "Open Excel, create a new workbook, and populate the first sheet with sales data"
- "List all running Windows processes and identify any high CPU consumers"
- "Send an Outlook email to the team with a summary of today's completed tasks"
- "Run a JavaScript script to scan a directory and return all file names matching a pattern"

Troubleshooting WelsonJS

cscript app.js fails with 'Access is denied' or execution policy errors

If running through PowerShell, check the execution policy with `Get-ExecutionPolicy` and set it to RemoteSigned with `Set-ExecutionPolicy RemoteSigned -Scope CurrentUser`. For cscript directly, ensure the script file is not blocked — right-click the .js file, select Properties, and click Unblock.

Office automation scripts fail with COM object errors

Office automation requires Microsoft Office to be installed on the machine. Run the script as the same user account that has Office licensed and activated. Ensure Excel/Word/Outlook are closed before the script opens them, as a running instance may lock the COM object.

MCP client cannot connect to the WelsonJS MCP server

Check the project wiki at github.com/gnh1201/welsonjs/wiki/MCP-server for the exact startup command and port configuration. Ensure Windows Firewall is not blocking the port the MCP server listens on.

Frequently Asked Questions about WelsonJS

What is WelsonJS?

WelsonJS is a Model Context Protocol (MCP) server that welsonjs - build a windows app on the windows built-in javascript engine It connects AI assistants to external tools and data sources through a standardized interface.

How do I install WelsonJS?

Follow the installation instructions on the WelsonJS GitHub repository. Clone the repo, install dependencies, and add the server config to your AI client.

Which AI clients work with WelsonJS?

WelsonJS works with all major MCP-compatible AI clients including Claude Desktop, Claude Code, Cursor, VS Code (GitHub Copilot), Windsurf, and Cline.

Is WelsonJS free to use?

Yes, WelsonJS is open source and available under the GPL-3.0 license. You can use it freely in both personal and commercial projects.

Learn More About MCP Servers

Getting Started with MCP

Set up your first MCP server in minutes

MCP Setup Guide

Configure MCP in Claude, Cursor & VS Code

All MCP Tutorials

18+ hands-on guides for developers

MCP FAQ

40+ answers about Model Context Protocol

WelsonJS Alternatives — Similar Developer Tools Servers

Looking for alternatives to WelsonJS? Here are other popular developer tools servers you can use with Claude, Cursor, and VS Code.

Ecc

★ 188.2k

The agent harness performance optimization system. Skills, instincts, memory, security, and research-first development for Claude Code, Codex, Opencode, Cursor and beyond.

Javaguide

★ 155.8k

Java 面试 & 后端通用面试指南，覆盖计算机基础、数据库、分布式、高并发、系统设计与 AI 应用开发

Gemini CLI

★ 104.5k

A secure MCP server that wraps the Google Gemini CLI, allowing clients to query Gemini models using local OAuth sessions without requiring an API key. It provides tools for model interaction and diagnostics with built-in protection against command in

Awesome MCP Servers

★ 87.3k

⭐ Curated list of Model Context Protocol (MCP) servers - tools that extend Claude Desktop, Cursor, Windsurf, and other MCP clients with custom capabilities.

MCP Servers

★ 86.0k

Model Context Protocol Servers

CC Switch

★ 77.5k

A cross-platform desktop All-in-One assistant for Claude Code, Codex, OpenCode, OpenClaw, Gemini CLI & Hermes Agent. Only official website: ccswitch.io

Browse More Developer Tools MCP Servers

Explore all developer tools servers available in the MCPgee directory. Each server includes setup guides for Claude, Cursor, and VS Code.

Developer ToolsBrowse All Servers

Quick Config Preview

{ "mcpServers": { "welsonjs": { "command": "npx", "args": ["-y", "welsonjs"] } } }

Add this to your claude_desktop_config.json or .cursor/mcp.json

Read the full setup guide →

Ready to use WelsonJS?

Browse our complete directory of 33,000+ MCP servers, read setup guides for your editor, and start building with the Model Context Protocol.

33,000+ ServersFree & Open SourceStep-by-Step Guides
Explore All ServersRead Our Guides