decompdecomp is an app that decompiles games you own. AI agents write C or C++ for each function of the game. The game's original compiler builds it. When the result is the same as the game, byte for byte, the function is matched. In the end you get a project that builds your game again, exactly.

New in 1.0.3-alpha: much faster, in its own window. The app is ready the moment it opens (3.7 s before, 15 ms now). The map of a big game updates ten times faster after a match. With 16 agents on two games, the app answers in under a tenth of a second (1.4 s before), and agents restart by themselves after a crash or a usage limit.

_{The app on Demo Quest 64, the demo ROM that comes with it. To keep the recording short, the helper is a stand-in for a model that hands in the demo's own C; the app compiles and judges every function for real.}

Install

decompdecomp runs on Linux, on a 64-bit Intel or AMD PC. Install it with one command. The installer also gets the free compilers and keeps decompdecomp up to date:

curl -fsSL https://decomp.ndelic.com/install.sh | bash

Or install a package from the releases:

sudo apt install ./decompdecomp_*_amd64.deb        # Debian, Ubuntu, Pop!_OS, Mint
sudo dnf install ./decompdecomp-*.x86_64.rpm       # Fedora
chmod +x decompdecomp-*-x86_64.AppImage && ./decompdecomp-*-x86_64.AppImage   # any other distribution

Windows and macOS aren't supported in this version.

Start

Type decomp, or open decompdecomp from your apps menu. It opens in a window of its own.

1. Open a game. Pick a ROM, a disc image or a program file of a game that you own. To try the app first, open Demo Quest 64.
2. Start agents. Any model with an API key (DeepSeek, OpenRouter, OpenAI, a local model), or Claude Code, Codex, opencode and Antigravity CLI. Run several, and different models: they work on different functions at the same time.
3. Watch the map. Each square is a function. It turns green when its function matches. The autopilot matches the easy ones for free, before any agent starts.
4. Export (in the project's header). You get a decomp project that builds your game again, byte for byte.

You can also continue a community decomp: paste the address of its repository and pick your own copy of its game.

When you close the window while agents work, decompdecomp asks you: stop them and quit, or keep them working. Quit ends the app and everything it started.

Coming from an older version (1.0.x)

Your projects stay. The new version opens the same ~/Decomp folder, with every match, name and note in it.

1. Install the new version the same way as before: the install command above, or the new .deb, .rpm or AppImage. The installer removes an older .deb or .rpm of decompdecomp, so your apps menu shows one. Going the other way, from the install command to a package? Remove the old copy first: uv tool uninstall decompnet.
2. Start it with decomp or from your apps menu. It opens in its own window now, not in your browser.
3. Start your agents again. Helper agents that were working in the old version don't restart by themselves the first time. Open each project and start them; from then on they restart by themselves.

What changed on the way:

• Agents run inside the app only. decomp connect and decomp mcp are gone. On its first start, the new version removes the old decomp entries from your agents' settings (Claude Code, Codex, opencode, Antigravity and others), and its home page says what it removed. Before that, those entries started the old app again whenever you closed it.

• The Source tab is now the Export button in the project's header.

• Windows (WSL) isn't supported in this version. Windows comes back in 1.0.4: until then, stay on 1.0.2. In its Settings, untick Install updates by itself and Look for updates. Updated already? This version turns both off, and its old browser tab shows how to go back. In PowerShell:

  wsl --terminate decomp-wtf
  wsl -d decomp-wtf -u decomp --exec /home/decomp/.local/bin/uv tool install --force --python 3.12 "decompnet @ https://github.com/n-delic/decompdecomp/archive/refs/tags/v1.0.2-alpha.tar.gz"
  wsl -d decomp-wtf -u root --exec sh -c "echo 'export DECOMP_TRAY=0' >> /etc/profile.d/decomp-wtf.sh"

  The last line turns off 1.0.2's tray icon: with the system packages 1.0.3's window uses, it made 1.0.2 quit at start ("127.0.0.1 refused to connect").

  Then start decompdecomp as before. To move to Linux instead: your projects are in \\wsl.localhost\decomp-wtf\home\decomp\Decomp. Copy that whole folder to ~/Decomp on a Linux computer, with the hidden .decomp folder in it, and install decompdecomp there: it finds every project in it.

Moving to another computer

decompdecomp saves the work on each N64 and PlayStation 2 project as plain files in the project's progress/ folder, every few minutes: matched C, best attempts, headers, names, notes and settings. It never contains the game, so you can keep it in a git repository. GameCube, Wii and PC projects and community decomps are git repositories already: push them.

The simplest way is to copy your whole ~/Decomp folder to the same place on the new computer. Copy the hidden .decomp folder in it too: it holds the matches of every project. decompdecomp then finds every project. To take a single N64 or PlayStation 2 project, or to keep it in git:

1. Copy the project's progress/ folder to the new computer, or push it to a git repository.
2. On the new computer, in decompdecomp: Open a saved project. Pick the folder (or paste the repository's address) and your own copy of the game.
3. decompdecomp checks it's the same game, rebuilds the project, and judges every saved function again.

Platforms

Platform	Status
Nintendo 64	Recommended
PlayStation 2	Beta
GameCube, Wii	Beta
Windows PC games	Beta
PlayStation, Game Boy Advance, DS, 3DS, PSP, Switch, Xbox, Xbox 360	Community decomps only

1.0.3 rewrote most of the app, so every platform needs testing again, Nintendo 64 too. Try it on a game you own and tell us how it went: what worked, what didn't, what was confusing. Reports are how a platform goes from beta to recommended.

Proprietary compilers (CodeWarrior, Visual C++, IDO) are installed only after you accept their licenses in the app.

Questions people ask

Is this just Ghidra? No. Ghidra (and IDA) show you C so you can read a program. That C usually doesn't compile, and when it does, the game's compiler makes different machine code from it. decompdecomp keeps a function only when its C, built by the game's own compiler, gives exactly the original bytes. That's what lets the result build the game again, the base for ports and mods.

What does the C look like? At first, raw. A match proves the code is right, not that it's easy to read. Here is one function of Demo Quest 64 as the autopilot matched it, and the same function made readable. Both compile to the same bytes:

/* As matched */
void func_80000A0C(s32 arg0) {
    s32 temp_v0;

    temp_v0 = D_8004AE30 + (arg0 * (D_8004AE58 + 1));
    D_8004AE30 = temp_v0;
    if (temp_v0 > 0xF423F) {
        D_8004AE30 = 0xF423F;
    }
}

/* Made readable: adds points for a hit, times the combo, up to the highest score. */
void add_score(s32 points) {
    g_score += points * (g_player.combo + 1);
    if (g_score > MAX_SCORE) {
        g_score = MAX_SCORE;
    }
}

Agents do that second step too: once half a game matches, Start agents offers Polish matched code. Helpers name functions, globals and parameters, describe structs in the shared header and add a comment, and a change is kept only when the function still matches byte for byte. Names are the agent's reading of the code: the bytes prove what a function does, not what its author called it.

Has a whole game been decompiled with it? Not yet. Games get far (hundreds or thousands of matched functions), and the export rebuilds the game byte for byte from matched C plus assembly for what isn't matched yet. A game at 100%, polished, is the goal, and the first one will be announced here.

Help make it better

decompdecomp is built in the open, and it's meant to be easy to work on. Read CONTRIBUTING.md first. A copy of decompdecomp that runs from a git checkout is a separate app, with its own folder, so it never touches the projects of the decompdecomp you have installed.

• The guide: how it works, agents, teams, platforms and the export.
• ROADMAP.md: what's planned, and which feature works on which platform.
• Issues: problems and requests.
• Discord: questions, progress on your games, and talking with the people building it.

Use it responsibly

• Use only games that you own. decompdecomp contains no game code and supplies no ROMs.
• Everything runs on your computer. Nothing of your game is sent anywhere, except to the AI model you choose.
• Do not publish the code that it makes from a game. That code belongs to the rights holder of the game.
• Follow the rules of any project that you contribute to.

Credits

decompdecomp continues decomp.wtf by Sam Wolfs (@i12bp8), who made it up to version 0.10.6 and then archived it. Thank you, Sam. decompdecomp is not related to decomp.wtf, and its author does not endorse it.

decompdecomp uses splat, spimdisasm, objdiff, decomp-toolkit, m2c, Ghidra, decomp-permuter, wibo and the decompals compilers. The guide lists them.

License

decompdecomp is free software under the GNU Affero General Public License version 3 © 2026 NDelic. Anyone who gives or sells a copy of it, changed or not, must give its full source under the same license. So must anyone who runs a changed copy for others to use over a network, a hosted room for example.

The code that came from decomp.wtf was released under the MIT license by Sam Wolfs; its notice is in LICENSE-decomp.wtf.

_{Not related to Nintendo, Sony or Microsoft. Platform names are trademarks of their owners.}