How do I install the Validate Vst3 Editorhost skill?

Run npx skillmds@latest add tomevault-io/validate-vst3-editorhost in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

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Is Validate Vst3 Editorhost free to use?

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Who published Validate Vst3 Editorhost?

tomevault-io (@tomevault-io) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Validate Vst3 Editorhost by tomevault-io

Name: Validate Vst3 Editorhost
Author: tomevault-io

Validate Vst3 Editorhost

Test VST3 plugin UIs (.vst3 bundles) using Steinberg's EditorHost without a full DAW. Use when user says "test the plugin UI", "open in editorhost", "show the .vst3 editor", or wants to visually inspect the VST3 editor. For functional validation use validate-vst3 instead. Use when this capability is needed.

tomevault-io Updated Sep 17, 2026

File contents

VST3 EditorHost

Minimal VST3 host for testing plugin UIs without a full DAW.

Plugin Install Locations

editorhost accepts a direct path to a .vst3 bundle.

Platform	User Location	System Location
macOS	`~/Library/Audio/Plug-Ins/VST3/`	`/Library/Audio/Plug-Ins/VST3/`
Windows	`%LOCALAPPDATA%\Programs\Common\VST3\`	`C:\Program Files\Common Files\VST3\`
Linux	`~/.vst3/`	`/usr/lib/vst3/` or `/usr/local/lib/vst3/`

Instructions

Build EditorHost from the VST3 SDK if not already built (see Building EditorHost below)
Run: editorhost /path/to/plugin.vst3
The plugin UI window should appear — verify layout, controls, and resizing
Test multiple editor instances with --secondWindow
If the UI doesn't appear, verify the plugin passes validator tests first

Usage

# Basic usage - load plugin and show UI
editorhost /path/to/plugin.vst3

# With component handler (tests host callbacks)
editorhost --componentHandler /path/to/plugin.vst3

# Open second window (tests multiple editor instances)
editorhost --secondWindow /path/to/plugin.vst3

# Specify a particular effect class by UID
editorhost --uid "ABCD1234..." /path/to/plugin.vst3

Binary Locations

Platform	Typical Path
macOS	`<vst3sdk>/build/bin/Release/editorhost.app/Contents/MacOS/editorhost`
Windows	`<vst3sdk>\build\bin\Release\editorhost.exe`
Linux	`<vst3sdk>/build/bin/Release/editorhost`

Building EditorHost

Clone the VST3 SDK if you don't have it, then build:

cd <vst3sdk>
cmake -B build -G Ninja -DCMAKE_BUILD_TYPE=Release
cmake --build build --target editorhost

Linux: Requires X11 and GTK3 development libraries:

# Debian/Ubuntu
sudo apt install libx11-dev libgtkmm-3.0-dev libxcb-util-dev libxcb-cursor-dev libxcb-keysyms1-dev libxcb-xkb-dev

# Fedora
sudo dnf install libX11-devel gtkmm3.0-devel xcb-util-devel xcb-util-cursor-devel xcb-util-keysyms-devel libxkbcommon-x11-devel

Troubleshooting

Plugin doesn't load

Check the plugin path is correct
Verify the plugin passes validator tests first
Check logs: Console.app (macOS), Event Viewer (Windows), or stderr (Linux)

UI doesn't appear

The plugin might not have an editor (hasEditor() returns false)
Check if createEditor() is returning a valid view
Linux: Ensure X11 display is available (echo $DISPLAY)

UI appears but is blank/wrong size

Check defaultEditorSize() returns valid dimensions
For WebView UIs, check the HTML content is being set correctly
Try with --secondWindow to see if the issue is with first-time setup

Source: iPlug3/audio-plugin-dev-skills — distributed by TomeVault.

---name: validate-vst3-editorhostdescription: Test VST3 plugin UIs (.vst3 bundles) using Steinberg's EditorHost without a full DAW. Use when user says "test the plugin UI", "open in editorhost", "show the .vst3 editor", or wants to visually inspect the VST3 editor. For functional validation use validate-vst3 instead. Use when this capability is needed.---# VST3 EditorHostMinimal VST3 host for testing plugin UIs without a full DAW.## Plugin Install Locations`editorhost` accepts a direct path to a `.vst3` bundle.| Platform | User Location | System Location ||----------|--------------|-----------------|| macOS | `~/Library/Audio/Plug-Ins/VST3/` | `/Library/Audio/Plug-Ins/VST3/` || Windows | `%LOCALAPPDATA%\Programs\Common\VST3\` | `C:\Program Files\Common Files\VST3\` || Linux | `~/.vst3/` | `/usr/lib/vst3/` or `/usr/local/lib/vst3/` |## Instructions1. Build EditorHost from the VST3 SDK if not already built (see Building EditorHost below)2. Run: `editorhost /path/to/plugin.vst3`3. The plugin UI window should appear — verify layout, controls, and resizing4. Test multiple editor instances with `--secondWindow`5. If the UI doesn't appear, verify the plugin passes `validator` tests first## Usage```bash# Basic usage - load plugin and show UIeditorhost /path/to/plugin.vst3# With component handler (tests host callbacks)editorhost --componentHandler /path/to/plugin.vst3# Open second window (tests multiple editor instances)editorhost --secondWindow /path/to/plugin.vst3# Specify a particular effect class by UIDeditorhost --uid "ABCD1234..." /path/to/plugin.vst3```### Binary Locations| Platform | Typical Path ||----------|-------------|| macOS | `<vst3sdk>/build/bin/Release/editorhost.app/Contents/MacOS/editorhost` || Windows | `<vst3sdk>\build\bin\Release\editorhost.exe` || Linux | `<vst3sdk>/build/bin/Release/editorhost` |## Building EditorHostClone the [VST3 SDK](https://github.com/steinbergmedia/vst3sdk) if you don't have it, then build:```bashcd <vst3sdk>cmake -B build -G Ninja -DCMAKE_BUILD_TYPE=Releasecmake --build build --target editorhost```**Linux**: Requires X11 and GTK3 development libraries:```bash# Debian/Ubuntusudo apt install libx11-dev libgtkmm-3.0-dev libxcb-util-dev libxcb-cursor-dev libxcb-keysyms1-dev libxcb-xkb-dev# Fedorasudo dnf install libX11-devel gtkmm3.0-devel xcb-util-devel xcb-util-cursor-devel xcb-util-keysyms-devel libxkbcommon-x11-devel```## Troubleshooting### Plugin doesn't load- Check the plugin path is correct- Verify the plugin passes `validator` tests first- Check logs: Console.app (macOS), Event Viewer (Windows), or stderr (Linux)### UI doesn't appear- The plugin might not have an editor (`hasEditor()` returns false)- Check if `createEditor()` is returning a valid view- **Linux**: Ensure X11 display is available (`echo $DISPLAY`)### UI appears but is blank/wrong size- Check `defaultEditorSize()` returns valid dimensions- For WebView UIs, check the HTML content is being set correctly- Try with `--secondWindow` to see if the issue is with first-time setup---> Source: [iPlug3/audio-plugin-dev-skills](https://github.com/iPlug3/audio-plugin-dev-skills) — distributed by [TomeVault](https://tomevault.io).

Frequently asked questions