kwin-mcp 0.2.0
MCP server for Linux desktop GUI automation on KDE Plasma 6 Wayland via isolated KWin virtual sessions
Requires Python: >=3.12
Keywords: mcp, kwin, kde, wayland, gui-automation, plasma, testing

# kwin-mcp

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A [Model Context Protocol (MCP)](https://modelcontextprotocol.io/) server for **Linux desktop GUI automation** on **KDE Plasma 6 Wayland**. It lets AI agents like [Claude Code](https://docs.anthropic.com/en/docs/claude-code) launch, interact with, and observe any Wayland application (Qt, GTK, Electron) in a fully isolated virtual KWin session — without touching the user's desktop.

## Why kwin-mcp?

- **Isolated sessions** — Each session runs in its own `dbus-run-session` + `kwin_wayland --virtual` sandbox. Your host desktop is never affected.
- **No screenshots required for interaction** — The AT-SPI2 accessibility tree gives the AI agent structured widget data (roles, names, coordinates, states, available actions), so it can interact with UI elements without relying solely on vision.
- **Zero authorization prompts** — Uses KWin's private EIS (Emulated Input Server) D-Bus interface directly, bypassing the XDG RemoteDesktop portal. No user confirmation dialogs.
- **Works with any Wayland app** — Anything that runs on KDE Plasma 6 Wayland works: Qt, GTK, Electron, and more. Input is injected via the standard `libei` protocol.

## Quick Start

> Requires KDE Plasma 6 on Wayland. See [System Requirements](#system-requirements) for details.

**1. Install**

```bash
# Using uv (recommended)
uv tool install kwin-mcp

# Or using pip
pip install kwin-mcp
```

**2. Configure Claude Code**

Add to your project's `.mcp.json`:

```json
{
  "mcpServers": {
    "kwin-mcp": {
      "command": "uvx",
      "args": ["kwin-mcp"]
    }
  }
}
```

**3. Use it**

Ask Claude Code to launch and interact with any GUI application:

```
Start a KWin session, launch kcalc, and press the buttons to calculate 2 + 3.
```

Claude Code will autonomously start an isolated session, launch the app, read the accessibility tree to find buttons, click them, and take a screenshot to verify the result.

## Features

- **Session management** — Start and stop isolated KWin Wayland sessions with configurable screen resolution
- **Screenshot capture** — Capture the virtual display as PNG via KWin's ScreenShot2 D-Bus interface
- **Accessibility tree** — Read the full AT-SPI2 widget tree with roles, names, states, coordinates, and available actions
- **Element search** — Find UI elements by name, role, or description (case-insensitive)
- **Mouse input** — Click (left/right/middle, single/double), move, scroll (vertical/horizontal), and drag with smooth interpolation
- **Keyboard input** — Type text (full US QWERTY layout) and press key combinations with modifier support (Ctrl, Alt, Shift, Super)

## System Requirements

| Requirement | Details |
|-------------|---------|
| **OS** | Linux with KDE Plasma 6 (Wayland session) |
| **Python** | 3.12 or later |
| **KWin** | `kwin_wayland` with `--virtual` flag support (KDE Plasma 6.x) |
| **libei** | Usually bundled with KWin 6.x (EIS input emulation) |
| **spectacle** | KDE screenshot tool (CLI mode) |
| **AT-SPI2** | `at-spi2-core` for accessibility tree support |
| **PyGObject** | GObject introspection Python bindings |
| **D-Bus** | `dbus-python` bindings |

### Installing System Dependencies

<details>
<summary><strong>Arch Linux / Manjaro</strong></summary>

```bash
sudo pacman -S kwin spectacle at-spi2-core python-gobject dbus-python-common
```

</details>

<details>
<summary><strong>Fedora (KDE Spin)</strong></summary>

```bash
sudo dnf install kwin-wayland spectacle at-spi2-core python3-gobject dbus-python
```

</details>

<details>
<summary><strong>openSUSE (KDE)</strong></summary>

```bash
sudo zypper install kwin6 spectacle at-spi2-core python3-gobject python3-dbus-python
```

</details>

<details>
<summary><strong>Kubuntu / KDE Neon</strong></summary>

```bash
sudo apt install kwin-wayland spectacle at-spi2-core python3-gi gir1.2-atspi-2.0 python3-dbus
```

</details>

## Installation

### Using uv (recommended)

```bash
uv tool install kwin-mcp
```

### Using pip

```bash
pip install kwin-mcp
```

### From source

```bash
git clone https://github.com/isac322/kwin-mcp.git
cd kwin-mcp
uv sync
uv run kwin-mcp
```

## Configuration

### Claude Code

Add to your project's `.mcp.json`:

```json
{
  "mcpServers": {
    "kwin-mcp": {
      "command": "uvx",
      "args": ["kwin-mcp"]
    }
  }
}
```

Or if installed globally:

```json
{
  "mcpServers": {
    "kwin-mcp": {
      "command": "kwin-mcp"
    }
  }
}
```

### Claude Desktop

Add to your `claude_desktop_config.json`:

```json
{
  "mcpServers": {
    "kwin-mcp": {
      "command": "uvx",
      "args": ["kwin-mcp"]
    }
  }
}
```

### Running Directly

```bash
# As an installed script
kwin-mcp

# As a Python module
python -m kwin_mcp
```

## Available Tools

### Session Management

| Tool | Parameters | Description |
|------|-----------|-------------|
| `session_start` | `app_command?`, `screen_width?`, `screen_height?` | Start an isolated KWin Wayland session, optionally launching an app |
| `session_stop` | _(none)_ | Stop the session and clean up all processes |

### Observation

| Tool | Parameters | Description |
|------|-----------|-------------|
| `screenshot` | `include_cursor?` | Capture a screenshot of the virtual display (saved as PNG, returns file path) |
| `accessibility_tree` | `app_name?`, `max_depth?` | Get the AT-SPI2 widget tree with roles, names, states, and coordinates |
| `find_ui_elements` | `query`, `app_name?` | Search for UI elements by name, role, or description (case-insensitive) |

### Mouse Input

| Tool | Parameters | Description |
|------|-----------|-------------|
| `mouse_click` | `x`, `y`, `button?`, `double?`, `screenshot_after_ms?` | Click at coordinates (left/right/middle, single/double) |
| `mouse_move` | `x`, `y`, `screenshot_after_ms?` | Move the cursor to coordinates without clicking |
| `mouse_scroll` | `x`, `y`, `delta`, `horizontal?` | Scroll at coordinates (positive = down/right, negative = up/left) |
| `mouse_drag` | `from_x`, `from_y`, `to_x`, `to_y`, `screenshot_after_ms?` | Drag from one point to another with smooth interpolation |

### Keyboard Input

| Tool | Parameters | Description |
|------|-----------|-------------|
| `keyboard_type` | `text`, `screenshot_after_ms?` | Type a string of text character by character (US QWERTY layout) |
| `keyboard_key` | `key`, `screenshot_after_ms?` | Press a key or key combination (e.g., `Return`, `ctrl+c`, `alt+F4`, `shift+Tab`) |

> **Frame capture:** Action tools accept an optional `screenshot_after_ms` parameter (e.g., `[0, 50, 100, 200, 500]`) that captures screenshots at specified delays (in milliseconds) after the action completes. This is useful for observing transient UI states like hover effects, click animations, and menu transitions without extra MCP round-trips.

## How It Works

```
Claude Code / AI Agent
  │
  │  MCP (stdio)
  ▼
kwin-mcp server
  │
  ├── session_start ─────────► dbus-run-session
  │                               ├── at-spi-bus-launcher
  │                               └── kwin_wayland --virtual
  │                                      └── [your app]
  │
  ├── screenshot ────────────► spectacle (via D-Bus)
  │
  ├── accessibility_tree ────► AT-SPI2 (via PyGObject)
  ├── find_ui_elements ──────► AT-SPI2 (via PyGObject)
  │
  ├── mouse_* / keyboard_* ─► KWin EIS D-Bus ──► libei
  │   └── screenshot_after_ms ► KWin ScreenShot2 D-Bus (fast frame capture)
```

### Triple Isolation

kwin-mcp provides three layers of isolation from the host desktop:

1. **D-Bus isolation** — `dbus-run-session` creates a private session bus. The isolated session's services (KWin, AT-SPI2, portals) are invisible to the host.
2. **Display isolation** — `kwin_wayland --virtual` creates its own Wayland compositor with a virtual framebuffer. No windows appear on the host display.
3. **Input isolation** — Input events are injected through KWin's EIS interface into the isolated compositor only. The host desktop receives no input from kwin-mcp.

### Input Injection

Mouse and keyboard events are injected through KWin's private `org.kde.KWin.EIS.RemoteDesktop` D-Bus interface. This returns a `libei` file descriptor that allows low-level input emulation without requiring the XDG RemoteDesktop portal (which would show a user authorization dialog). The connection uses:

- **Absolute pointer positioning** for precise coordinate-based interaction
- **evdev keycodes** with full US QWERTY mapping for keyboard input
- **Smooth drag interpolation** (10+ intermediate steps) for realistic drag operations

### Screenshot Capture

The `screenshot` tool uses `spectacle` CLI for reliable full-screen capture. For action tools with the `screenshot_after_ms` parameter, screenshots are captured directly via the KWin `org.kde.KWin.ScreenShot2` D-Bus interface, which is much faster (~30-70ms vs ~200-300ms per frame) because it avoids process spawn overhead. Raw ARGB pixel data is read from a pipe and converted to PNG using Pillow.

### Accessibility Tree

The AT-SPI2 accessibility bus within the isolated session is queried via PyGObject (`gi.repository.Atspi`). This provides a structured tree of all UI widgets with their roles (button, text field, menu item, etc.), names, states (focused, enabled, visible, etc.), screen coordinates, and available actions (click, toggle, etc.).

## Limitations

- **US QWERTY keyboard layout only** — Other keyboard layouts are not yet supported for text typing.
- **KDE Plasma 6+ required** — Older KDE versions or other Wayland compositors (GNOME, Sway) are not supported.
- **AT-SPI2 availability varies** — Some applications may not fully expose their widget tree via AT-SPI2.

## Contributing

Contributions are welcome! Please open an issue or pull request on [GitHub](https://github.com/isac322/kwin-mcp).

```bash
git clone https://github.com/isac322/kwin-mcp.git
cd kwin-mcp
uv sync
uv run ruff check src/
uv run ruff format --check src/
uv run ty check src/
```

## License

[MIT](LICENSE)