kwin-mcp

An MCP (Model Context Protocol) server that controls native Wayland windows on KDE Plasma from an AI agent.

It does what cua-driver cannot on Linux/Wayland: see and drive the real desktop. cua-driver (trycua) only enumerates X11/XWayland clients, so on a KDE Wayland session it sees 1 of ~20 windows. kwin-mcp sees all of them.

It is built entirely on KDE-native primitives, so it needs no modifications to trycua's binary and no root daemon. You point your MCP client (Claude Code, Codex, Hermes, etc.) at server.py and get the same capabilities cua offers on X11: window listing, screenshots, clicks, typing, dragging, key presses, and (optionally) AT-SPI element targeting.

Install

kwin-mcp targets KDE Plasma on Wayland. It is a Python MCP server, so any MCP host (Claude Code, Codex, Cursor, Zed, Hermes) can use it.

One command (recommended)

kwin-mcp-server is published to PyPI, so install is a single command with no git clone and no build:

pipx install kwin-mcp-server        # or: uv tool install kwin-mcp-server
kwin-mcp --doctor                    # print the readiness report
kwin-mcp                              # start the stdio MCP server

Then give it system access and wire it into your agent (both shown below).

System deps + input permission (one-time)

sudo pacman -S kdotool spectacle                 # Arch
sudo usermod -aG input "$USER"                   # allow /dev/uinput
# log out and back in so the new group applies

Not on Arch? See the Dependencies table below for the per-distro package names.

Wire it into your agent

Any MCP host can point at the kwin-mcp command. Use setup.sh for the convenience of auto-wiring your agent's config (it preflights, prints exactly what is missing, and never half-wires):

git clone https://github.com/Samthesurf/kwin-mcp.git /tmp/kwin-mcp && cd /tmp/kwin-mcp
./setup.sh hermes     # or: claude | codex | cursor | zed

Or wire it manually by running the kwin-mcp command in your agent's MCP config. ./setup.sh verify launches the real server and confirms it reports ready; ./setup.sh help prints usage; ./setup.sh check runs only the preflight.

Manual run (no agent)

kwin-mcp              # stdio MCP server
kwin-mcp --doctor     # readiness report
kwin-mcp --check      # dependency preflight

What it can do

Windows are identified by a stable KDE window UUID of the form {xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx} (exactly what kdotool prints).

Readiness report (doctor) and safety contract

doctor / kwin-mcp-doctor

Run kwin-mcp --doctor (or kwin-mcp-doctor) to get a single structured JSON document describing the desktop, the windowing backend (with a live window list probe), the input path, AT-SPI, the screenshot path, and XDG portal availability. It ends with a readiness summary carrying explicit blockers and a recommended_next_step, so an MCP host or a human can render one report instead of parsing prose:

kwin-mcp --doctor | jq .readiness

The same report is exposed as the doctor MCP tool.

MCP safety annotations

Since v0.2 every tool carries an MCP ToolAnnotations so hosts can warn before invoking a mutating tool:

Annotations are safety hints, not an authorization system. Treat any call that could submit, delete, send, or purchase as requiring user approval.

Dependencies

System packages (must be installed on the machine)

These are the KDE/Wayland tools the server shells out to. Install with your distro's package manager.

On Arch this machine already had kdotool, spectacle, grim, ydotool, slurp, and busctl available.

Kernel / group requirements (input)

Synthetic input is sent through a virtual device on /dev/uinput. You must:

1. Be a member of the input group:

   groups | grep -w input || sudo usermod -aG input "$USER"
   # then log out and back in
   

2. Have write access to /dev/uinput (group input owns it: crw-rw---- root input). No root daemon (ydotoold) is required because python-uinput opens the device directly as a group member.

Verify with:

ls -l /dev/uinput          # should show group 'input' with rw
id -nG | tr ' ' '\n' | grep -x input   # should print 'input'

Python packages

python -m venv .venv
. .venv/bin/activate
pip install -r requirements.txt
# AT-SPI element/action/value targeting + semantic clicks work out of the box:
# kwin-mcp talks to AT-SPI directly over D-Bus via jeepney (already a
# dependency), so no pyatspi is required. On distros where the legacy pyatspi
# module happens to be installed, it is used as a fallback backend.

Installed and verified on this build: mcp 1.28.1, python-uinput 1.0.1, Pillow 12.3.0 (Python 3.14).

Running

. .venv/bin/activate

# dependency preflight (also run automatically by setup.sh)
python server.py --check

# JSON readiness report
python server.py --doctor

# stdio MCP server (for Claude/Codex/Hermes MCP clients)
python server.py

# or via the convenience wrapper
python run.py

# Streamable HTTP transport on 127.0.0.1:8080
python server.py --http 8080

The smoothest path, however, is the one-command uvx setup described in the next section, which needs no local venv at all.

Wiring into an MCP client (one command)

The recommended way is uvx, the Python equivalent of npx: it downloads and runs the server on first use, then caches it. No clone, no venv, no manual install. After uvx runs once, the agent just launches uvx --from git+https://github.com/Samthesurf/kwin-mcp kwin-mcp.

Automatic (recommended): run the setup script, which checks dependencies and injects the correct config into your agent.

git clone https://github.com/Samthesurf/kwin-mcp.git /tmp/kwin-mcp && cd /tmp/kwin-mcp
./setup.sh hermes      # or: claude | codex | cursor | zed | check

setup.sh runs a preflight first. If a system dependency is missing it prints exactly what to install (e.g. sudo pacman -S kdotool) and stops, so you never end up with a half-wired, broken server. If all checks pass it writes the uvx --from ... kwin-mcp entry into the chosen agent's config.

Manual: point the client at the uvx launcher. Example (mcp-config.example.json):

{
  "mcpServers": {
    "kwin-mcp": {
      "command": "uvx",
      "args": ["--from", "git+https://github.com/Samthesurf/kwin-mcp", "kwin-mcp"]
    }
  }
}

• Hermes: ./setup.sh hermes writes it under mcp_servers in ~/.hermes/config.yaml, or paste the JSON there. Restart Hermes to load it. This replaces cua-driver for the computer_use toolset on a Wayland box.
• Claude Code: claude mcp add kwin-mcp -- uvx --from git+https://github.com/Samthesurf/kwin-mcp kwin-mcp
• Codex / Cursor / Zed: ./setup.sh codex|cursor|zed, or paste the JSON into their MCP config file.

The server is self-sufficient about its environment: when an MCP client does not forward DBUS_SESSION_BUS_ADDRESS / WAYLAND_DISPLAY / DISPLAY / XDG_RUNTIME_DIR, the server discovers the correct session values from /run/user/<uid>/ so kdotool and spectacle always work.

No API keys, no network calls, no cloud. Everything runs locally against your compositor.

Running from a local checkout (alternative)

If you prefer a local venv instead of uvx:

python -m venv .venv && . .venv/bin/activate
pip install -r requirements.txt
python server.py            # stdio MCP server
python server.py --check   # dependency preflight

How it works (and the Wayland caveats)

On Wayland there is no X server between apps and the compositor, so input cannot be injected "into a specific window" the way cua-driver does on X11. The bridge follows a focus-then-inject model:

1. kdotool windowactivate <uuid> raises and focuses the target window.
2. The virtual pointer (a python-uinput device) is moved to the target coordinate. Because the compositor applies mouse acceleration and uinput only emits relative motion, movement is closed-loop: read the real cursor, emit a bounded delta, re-read, repeat until within ~3 px. This makes absolute positioning deterministic.
3. The click / key / drag is emitted on the now-focused window.

What this costs versus X11 (inherent to Wayland, not a bug):

• No background targeting. The window must be focused first; the real cursor moves. It is not invisible the way background X11 input can be.
• Single cursor. Parallel multi-pointer drags (cua's parallel_mouse_drag) are not available on Wayland.
• Secure-input surfaces (some password fields, the lock screen) may reject synthetic input.
• Small focus race. Between focusing and injecting there is a brief window where focus could shift; the code waits ~250 ms after activation.

Screenshots use spectacle in background/non-interactive mode. On KDE Wayland --background can occasionally race the compositor and capture the lock-screen splash instead of the live desktop; the capture path adds a settle delay and a variance-based validation that retries up to 3 times, so the returned frame is always the real desktop.

AT-SPI (get_window_state, click_element, perform_action, set_value, semantic clicks) works for GTK/Qt/KDE apps that expose an accessibility tree. It talks to AT-SPI directly over D-Bus (via jeepney, a pure-Python client), so it needs no pyatspi and works on Arch; the legacy pyatspi module is used only as a fallback if present. It degrades gracefully to coordinate input when no AT-SPI backend is available.

Project layout

kwin-mcp/
├── server.py              # MCP server (FastMCP) exposing all tools
├── run.py                 # convenience entry point
├── requirements.txt
├── pyproject.toml
├── mcp-config.example.json
├── README.md
└── kwin_bridge/
    ├── __init__.py
    ├── windows.py         # kdotool wrapper: enumerate/geometry/focus/close
    ├── screenshot.py      # spectacle wrapper + crop + retry/validate
    ├── input.py           # /dev/uinput virtual pointer+keyboard, closed-loop move
    ├── a11y.py            # AT-SPI front-end (semantic resolve / action / value)
    ├── atspi_dbus.py      # pure-D-Bus AT-SPI backend (jeepney, no pyatspi)
    ├── doctor.py          # structured JSON readiness report
    └── preflight.py       # actionable dependency check

Testing

A quick smoke test against the live desktop:

. .venv/bin/activate
python - <<'PY'
from kwin_bridge import windows, screenshot, input as inp
ws = windows.list_windows()
print("windows:", len(ws))
wid = ws[0].window_id
print("capturing", wid)
p = screenshot.capture_window(wid, "/tmp/test.png")
print("shot:", p)
inp.click_window(wid, 100, 100)
inp.type_text("hello from kwin-mcp")
PY

License

MIT. Use it, fork it, ship it.