Prefixr

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What is Prefixr?

Prefixr is a desktop app for playing Windows games on Linux, made to be run by an AI agent as much as by you. Hand your game folders to an agent such as Claude Code and it does the setup through Prefixr's command line (see below), or do it yourself: in the window you add a game's .exe, pick a Wine or Proton prefix and a runner, and Prefixr takes care of the rest: it creates the prefix, launches the game through umu-launcher the way Steam launches Proton, applies protonfixes, installs DXVK and VKD3D-Proton for plain Wine builds, and lets you tune every game on its own.

It is built for people who want their GOG, Epic, Amazon, itch.io or standalone games next to their Steam library, without editing launch scripts. If you know Lutris, Bottles, Heroic or PortProton, Prefixr covers the same ground with a focus on prefixes: you can reuse an existing prefix from any of them as it is.

✨ Features

🎮 Game library	Grid and list views with search, a card size slider and sorting by name, last played, recently added or play time. Installed games and your stores' games to install in their own sections, a Continue playing row, a details panel per game with play time, size and settings, launch arguments and environment variables per game, desktop and app menu shortcuts.
🗂️ Organizing	Your own categories (Kids, Co-op, …), favorites and hidden games, as chips above the library. A game can be in several categories, and a store game keeps them when it's installed. An AI agent can sort a whole library into categories for you.
🩺 Compatibility	See before installing whether a game runs: its ProtonDB rating and whether umu-protonfixes has fixes for it, as badges on every card.
📦 Installers	Open a setup .exe with Install Prefixr from your file manager's Open With menu. The installer runs in the prefix you choose, and the shortcut it creates is offered as the game to add.
🍷 Prefixes	Create new Wine/Proton prefixes or import existing ones from Steam, Lutris, Bottles or PortProton. Each prefix is listed by the games that use it, with search and filters (unused, shared, not set up yet, folder missing) that keep a few hundred of them manageable. Install dependencies with winetricks and open winecfg, regedit and Wine's other tools from the app.
⬇️ Runners	Download Proton-GE, Proton-CachyOS and Wine (Kron4ek) from their GitHub releases, checksum-verified. Any Proton or Wine build you place or symlink in the runners folder shows up as well.
🚀 Launching	Proton games run through umu-launcher in the Steam Linux Runtime, with an automatic UMU ID lookup for protonfixes. Wine games get DXVK, VKD3D-Proton and wine-mono set up automatically.
🎛️ Per-game tuning	MangoHud with presets, GameMode, power profiles, , and every switch your runner supports. Set them once globally, override them per game.

See the user guide for a tour of every feature.

🤖 Let an AI agent run your library

Prefixr is built so that an AI coding agent such as Claude Code can do the work for you through its command line. You say what you want, the agent does it, and you watch the window update and play. Run prefixr skill install once, and Claude Code knows how to work with Prefixr from the start (more).

• Add games: it looks at your game folders, adds each game with the right runner and prefix, finds its protonfixes match, installs winetricks packages and picks the artwork.
• Install from your stores: it connects your Epic Games, GOG and Amazon accounts (you sign in once in the browser) and installs their games.
• Install from a setup file or a disc: give it an installer .exe or a disc image (.iso), and it runs the installer in a new prefix (silently where the installer allows it) and adds the game.
• Move games over: it carries over the fixes from old launch scripts or other launchers and copies your save games.
• Fix games: when a game doesn't start, it reads the log and changes the setup until it does.
• Test games: with a computer-use tool for the Linux desktop (see the tip below), it starts each game, looks at the screen, and marks it on its cover as working (✓), working with issues (!) or broken (✕), with a note on what it saw.
• Organize the library: it creates categories such as Kids and Adults and sorts every game into them, marks favorites and hides what you won't play.
• Keep notes: it writes down what it found (an offline login, why a setting is needed) with the game, for the next time.

You:   Add all games under /mnt/games/ to Prefixr. Each one has its own Wine and a
       start script; give them Proton-GE instead and keep the fixes from the scripts.
Agent: prefixr runner download proton-ge
       prefixr umu search "Fallout 4"
       prefixr game add --name "Fallout 4" --exe ".../Fallout4.exe" --prefix ~/Games/prefixes/fallout4 \
         --runner GE-Proton10-30 --umu-id 377160 --env DXVK_FRAME_RATE=58
       prefixr game artwork "Fallout 4"
       …

You:   Create the categories Kids and Adults and sort all my games into them.
Agent: prefixr library list --json
       prefixr category add Kids
       prefixr category add Adults
       prefixr category assign Kids epic:Fortnite gog:1207658924 "Stardew Valley"
       prefixr category assign Adults "Fallout 4" "Cyberpunk 2077"

When a game doesn't start, the agent reads its log with prefixr game log <game> --print and fixes the setup.

Tip: let the agent check that your games work. Give the agent a computer-use tool for the Linux desktop, an MCP server that lets it take screenshots and use the mouse and keyboard (for example Computer Use MCP Server for X11, or codex-computer-use-linux, which also works on Wayland). Then ask: "Add all games under /mnt/games/ and check whether each one starts." The agent launches every game, looks at what's on screen (the menu, a black window, an error dialog), stops it, and fixes or reports the ones that don't run. These are community projects that get full control of your desktop: read what they do before you install one. See Working with an AI agent.

📦 Installation

Download the latest build from the releases page:

Package	For	Install
.AppImage	Any distribution	chmod +x prefixr_*.AppImage && ./prefixr_*.AppImage
.deb	Debian, Ubuntu, Linux Mint, Pop!_OS	sudo apt install ./prefixr_*_amd64.deb
.rpm	Fedora, openSUSE, Nobara	sudo dnf install ./prefixr-*.x86_64.rpm
.flatpak	Any distribution with Flatpak (releases after 0.1.10)	flatpak install --user ./prefixr_*_x86_64.flatpak

On immutable distributions such as Bazzite or SteamOS, use the Flatpak or the AppImage. If the AppImage shows a blank window or crashes with EGL_BAD_PARAMETER, see Troubleshooting.

To build Prefixr yourself, follow Building from source.

✅ Requirements

• Linux on x86_64 with a Vulkan-capable GPU driver (Mesa or NVIDIA)
• 32-bit graphics libraries for older games, as your distribution packages them for Steam
• Optional: Steam (to import prefixes and add games to Steam), MangoHud, GameMode, power-profiles-daemon, Gamescope and vkBasalt for the matching settings

Prefixr downloads umu-launcher, runners, DXVK, VKD3D-Proton, wine-mono and winetricks itself when they're first needed. The getting started guide walks through the first game.

📚 Documentation

The documentation is also available as a website: firsttris.github.io/prefixr.

Guide	What's in it
Getting started	Install Prefixr and get your first game running
User guide	The library, prefixes, runners, per-game settings, artwork and Steam
Configuration & files	Where Prefixr keeps its data, command-line options, API keys
Command line & AI agents	Every command, JSON output, the Prefixr skill, and letting an AI agent set up, fix and organize your games
Troubleshooting & FAQ	Common problems and how to fix them
Development	Building from source, architecture, tests and releases

🤝 Contributing

Bug reports, ideas and pull requests are welcome. Please open an issue first for larger changes. The development guide explains how to set up the project, which checks CI runs, and how texts and translations work.

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License: GPL-3.0 · © Tristan Teufel and contributors Changed versions you pass on must stay under the GPL and come with their source code; a commercial license without these obligations is available via teufel-it.de. Prefixr is not affiliated with Valve, Steam, WineHQ, CodeWeavers or SteamGridDB.