Rhombus.WinFormsMcp 1.5.9

<p align="center"> <h1 align="center">Rhombus.WinFormsMcp</h1> <p align="center"><strong>Give AI agents eyes and hands for Windows Forms apps</strong></p> </p>

<p align="center"> <a href="https://github.com/fnrhombus/winforms-mcp/actions/workflows/ci.yml"><img src="https://github.com/fnrhombus/winforms-mcp/actions/workflows/ci.yml/badge.svg" alt="CI Status"></a> <a href="https://www.nuget.org/packages/Rhombus.WinFormsMcp"><img src="https://img.shields.io/nuget/v/Rhombus.WinFormsMcp" alt="NuGet Version"></a> <a href="https://www.npmjs.com/package/@fnrhombus/winforms-mcp"><img src="https://img.shields.io/npm/v/@fnrhombus/winforms-mcp" alt="NPM Version"></a> <a href="https://opensource.org/licenses/MIT"><img src="https://img.shields.io/badge/License-MIT-yellow.svg" alt="License: MIT"></a> </p>

<p align="center"> An <a href="https://modelcontextprotocol.io">MCP server</a> that lets Claude (and any MCP-compatible agent) launch, automate, screenshot, and preview WinForms applications — without touching a mouse. </p>

The problem

You're building a WinForms app with an AI coding agent. The agent can read and write your code, but it's blind — it can't see what the form looks like, can't click a button to test a workflow, and can't tell if the UI it just generated actually renders correctly.

The fix

One line in your MCP config. Now the agent can:

render_form in action

The agent reads your .Designer.cs, calls render_form, and gets back this — no build, no running app:

<p align="center"> <img src="https://raw.githubusercontent.com/wiki/fnrhombus/winforms-mcp/render-form-demo.png" alt="render_form output — Login Form" width="400"> </p>

It can then edit the layout, re-render, and iterate — a full visual feedback loop with no IDE, no build, and no human in the loop.

Quick start

Add to your MCP config and restart. Nothing else to install.

npx (requires Node.js):

{
  "mcpServers": {
    "winforms-mcp": {
      "command": "npx",
      "args": ["-y", "@fnrhombus/winforms-mcp"]
    }
  }
}

Standalone (no Node required) — download the zip from Releases, extract it, and point to the exe:

{
  "mcpServers": {
    "winforms-mcp": {
      "command": "C:/path/to/winformsmcp/winformsmcp.exe"
    }
  }
}

Note: Keep the extracted folder structure intact — render_form needs the rendererhost/ subdirectory alongside the exe.

That's it. The agent can now see and interact with any WinForms application on your machine.

Contributing

See CLAUDE.md for development guidelines. Git hooks (commit message validation and code formatting) are automatically configured on the first dotnet build or dotnet test.

Tools

Cross-framework rendering

render_form detects your project's target framework and dispatches to a matching out-of-process host:

Custom controls, third-party components, and framework-specific APIs all resolve correctly. Override with the TFM environment variable if needed.

Headless mode

Set HEADLESS=true to launch apps on a hidden Windows desktop (CreateDesktop API):

• Zero focus stealing — apps can't steal focus, show TopMost windows, or flash in the taskbar
• Full automation — element discovery, clicking, typing, and screenshots all work through UIA patterns and PrintWindow
• Mixed mode — headless and visible apps in the same session, each automatically routed to its correct desktop

{
  "mcpServers": {
    "winforms-mcp": {
      "command": "npx",
      "args": ["-y", "@fnrhombus/winforms-mcp"],
      "env": { "HEADLESS": "true" }
    }
  }
}

Note: send_keys and drag_drop require input simulation and only work on the visible desktop. Use type_text/set_value and click_element for headless processes.

Environment variables

Documentation

• Examples — common workflows and patterns
• Headless Mode — hidden desktop architecture and tool compatibility

Contributing

Contributions welcome! See issues for open items.

Support

If you find this project useful, consider supporting its development:

• GitHub Sponsors — Monthly sponsorship with public recognition
• Buy Me a Coffee — One-time or recurring donations

Your support helps maintain and improve this project!

License

MIT