Give AI agents eyes and hands for Windows Forms apps
An MCP server that lets Claude (and any MCP-compatible agent) launch, automate, screenshot, and preview WinForms applications — without touching a mouse.
--- ## 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: | | | |---|---| | **See forms without building** | `render_form` gives the agent a designer — the exact same rendering pipeline Visual Studio uses. Edit, re-render, iterate with no build and no human in the loop | | **Drive running apps** | Launch processes, find elements by name/type/ID, click, type, drag-drop, take screenshots | | **Work in the background** | Headless mode runs apps on a hidden desktop — zero focus stealing, zero disruption | | **Target any framework** | .NET Framework 4.x, .NET Core 3.x, .NET 5–9+. Auto-detected from your `.csproj` | ## Quick start **Claude Code plugin** (easiest): ``` /plugin marketplace add fnrhombus/claude-plugins /plugin install winforms-mcp@claude-plugins ``` **MCP config with npx** (requires Node.js): ```json { "mcpServers": { "winforms-mcp": { "command": "npx", "args": ["-y", "@fnrhombus/winforms-mcp"] } } } ``` **Standalone** (no Node required) — [download the zip from Releases](https://github.com/fnrhombus/winforms-mcp/releases), extract it, and point to the exe: ```json { "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. ## Tools | Category | Tools | Description | |----------|-------|-------------| | **Process** | `launch_app` `attach_to_process` `close_app` `get_process_status` | Start, attach to, and manage Windows processes | | **Discovery** | `find_element` `element_exists` `wait_for_element` `get_element_tree` | Locate UI elements by AutomationId, name, class, or control type | | **Interaction** | `click_element` `type_text` `set_value` `select_item` `click_menu_item` `drag_drop` `send_keys` | Click buttons, fill text boxes, select combo items, navigate menus | | **Visual** | `take_screenshot` `render_form` | Capture running apps or render `.Designer.cs` to PNG | ## Cross-framework rendering `render_form` detects your project's target framework and dispatches to a matching out-of-process host — the same rendering pipeline Visual Studio uses, so custom controls and third-party components resolve correctly. | Your project targets | Renderer host | |---|---| | .NET Framework 4.0–4.8.x | `net48` | | .NET Core 3.x | `netcoreapp3.1` | | .NET 5, 6, 7, 8, 9+ | `net8.0-windows` | Framework-specific APIs resolve correctly too. 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 ```json { "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 | Variable | Default | Description | |----------|---------|-------------| | `HEADLESS` | `false` | Run launched apps on a hidden desktop | | `TFM` | `auto` | Lock rendering to a specific framework (`net48`, `netcoreapp3.1`, `net8.0-windows`) | | `TELEMETRY_OPTOUT` | `false` | Disable all Application Insights telemetry (matches .NET CLI conventions) | ## Documentation - [Examples](https://github.com/fnrhombus/winforms-mcp/wiki/Examples) — common workflows and patterns - [Headless Mode](https://github.com/fnrhombus/winforms-mcp/wiki/Headless-Mode) — hidden desktop architecture and tool compatibility ## Contributing Contributions welcome — see [issues](https://github.com/fnrhombus/winforms-mcp/issues) for open items. Git hooks for commit validation and code formatting are configured automatically on first build. ## Support If you find this project useful, consider supporting its development: - **[GitHub Sponsors](https://github.com/sponsors/fnrhombus)** — Monthly sponsorship with public recognition - **[Buy Me a Coffee](https://buymeacoffee.com/fnrhombus)** — One-time or recurring donations Your support helps maintain and improve this project! ## License [MIT](LICENSE)