Ferret

Find and change values in your games. Health, gold, ammo: pick the number in the game's window, play a little, and Ferret finds where the game keeps it. Then set it, keep it from going down, and get it back automatically every time you play. For single-player games on Linux.

If you know Cheat Engine or GameConqueror (scanmem): Ferret is a memory editor in that family, made so you don’t need to know what a memory scan is.

_{The game is SuperTux, free and open source; its artwork is under its own free licenses. The GIF is sped up.}

Install

Download the .flatpak file from the latest release and install it (Ferret uses the GNOME runtime from Flathub, already set up on most distros):

flatpak install --user ferret-0.1.0-x86_64.flatpak

There are no automatic updates yet: install the new file when a new release comes out. Ferret is young: it works on the games listed below, and feedback on others is welcome (Send Feedback in its menu, or an issue here).

How it works

1. Open your game from the list of running games.

2. Click the number in the picture of the game window (or drag a box around it, around a health bar, or around a row of hearts). Ferret reads it, and learns how the game draws its digits as you go. If it can't read it, type the number instead.

3. Press Start and play. The bar at the top tells you when to keep your hands off and when it's your turn to change the number: pick up some coins, take a hit. Every change narrows the search. When a few places are left that all follow the number, Ferret writes test values to tell the real one from the game's display copies; if it still can't tell, you try them.

   

4. Save it with a name. Ferret works out how the game gets to the value, so it finds it again after the game restarts, usually within a second or two of opening the game.

5. Change it in the Values tab, or keep it in a range (Keep It: never below the number now). Limits keep working while you play, even with Ferret's window closed; a hotkey turns them off and on from inside the game.

   

Notifications tell you what Ferret needs while the game is in front, even in fullscreen.

Single-player only

Ferret refuses online games: games with anti-cheat running, online-only games and MMOs, games with Valve Anti-Cheat, and games that flag edited characters online (Elden Ring, the Souls games). If anti-cheat starts while Ferret is open, it lets go of the game at once. Games with a multiplayer mode, or with anti-cheat that isn't running, open with a warning to play offline.

There are no store lookups over the network. Ferret checks Steam's and Heroic's local cache for game info, has a copy of AreWeAntiCheatYet's list of games with anti-cheat, looks for anti-cheat programs running, and checks the game's folder for anti-cheat files.

Games

Native Linux games and Windows games under Proton or Wine, from Steam, Heroic, Lutris or anywhere else. Ferret finds values again by the game's own code, by the names Unreal, Unity (Mono and IL2CPP) and Godot games give their objects, or by pointer paths. Tried so far, among others: SuperTux, Terraria, Valheim, ULTRAKILL, Creeper World 4, Brotato, Lumencraft, Forager, Prey, Mass Effect: Andromeda, Starship Troopers: Ultimate Bug War!, Quake II RTX, Skyrim Special Edition, and Flash games in Ruffle. Java games (Shattered Pixel Dungeon) are only shown, not changed yet.

Values a game hides (memory scramblers like CodeStage Anti-Cheat Toolkit in some Unity games) can't be found: Ferret says so when you open such a game.

Sharing

• Export / import: a game's saved values as a small .ferret text file, or copied to paste in a chat. Imported values aren't changed until you confirm the game shows their number.
• Shared library: browse values other players shared for the same game, and share your own (only values you confirmed, nothing about you or your computer). When you confirm or remove a value you got from it, Ferret tells the library whether it worked.
• Send Feedback: a message to the developer, optionally with Ferret's log (your home folder's path taken out) and the game's saved values. You see exactly what's sent.

Ferret goes online only for these (its own server, on Cloudflare); nothing else leaves your computer.

Languages

English, German, Spanish, French, Italian, Polish, Brazilian Portuguese, Russian and Simplified Chinese. The translations are machine-made and not reviewed by native speakers yet: corrections are welcome (po/).

Building

Ferret is a flatpak (GTK 4 and libadwaita, written in Rust). It needs the GNOME 50 SDK and the Rust extension:

flatpak install --user flathub org.gnome.Sdk//50 org.freedesktop.Sdk.Extension.rust-stable//25.08 org.flatpak.Builder
# the crates, once and after changing dependencies (vendor/ is gitignored)
mv .cargo/config.toml .cargo/config.toml.off
flatpak run --share=network --filesystem="$PWD" --command=sh org.gnome.Sdk//50 \
    -c 'cd "$0" && /usr/lib/sdk/rust-stable/bin/cargo vendor --versioned-dirs vendor' "$PWD"
mv .cargo/config.toml.off .cargo/config.toml
# build and install
flatpak run org.flatpak.Builder --user --install --force-clean --disable-rofiles-fuse \
    build-dir io.github.Petru101.Ferret.yml
flatpak run io.github.Petru101.Ferret

The app is sandboxed; reading and writing a game's memory happens in a small helper (ferret-helper, Rust with only the standard library and libc, linked statically) that Ferret starts on the host with flatpak-spawn --host, because games run outside the sandbox. The game window comes through the ScreenCast portal: only the window you pick, never your desktop. If your system doesn't allow one program to read another's memory (kernel.yama.ptrace_scope), Ferret explains how to allow it.

flatpak run io.github.Petru101.Ferret --cli is a text interface used by the test scripts: test-game/ has a stand-in game and scripts that drive it (natively, under Proton and in the Steam Linux Runtime), and bench/ compares OCR engines on saved game frames.

Third-party data

• Numbers are read with PaddlePaddle's PP-OCRv6 small text detection and recognition models (PaddleOCR, Apache License 2.0), downloaded from PaddlePaddle's Hugging Face repositories at build time and run with rten.
• data/areweanticheatyet/games.json is a trimmed copy of AreWeAntiCheatYet's games.json (MIT License, Copyright © 2021 Starz0r, Curve; see data/areweanticheatyet/LICENSE and SOURCE). Refresh it with data/areweanticheatyet/update.sh before a release.
• The Rust crates Ferret is built from (MIT, Apache-2.0, BSD, ISC and similar licenses) are listed with their license texts in data/third-party/THIRD-PARTY-LICENSES.txt, installed with the app in /app/share/licenses/io.github.Petru101.Ferret/. Regenerate it with python3 data/third-party/update.py after changing dependencies.

Made with AI

Most of Ferret's code, its translations and this README were written by Claude (Anthropic's AI). Its author designed it, directed every change and tests it on real games.

License

GPL-3.0-or-later (LICENSE).