The Most Dangerous Repository Has a Forty-Year-Old Clean Room at Its Core

Deni split 20 GitHub repositories into five groups by purpose and assembled a reverse-engineering workstation. The original tweet says this is starting to get dangerous.

The grouping is worth looking at.

Analysis Core

REA, an MCP, plugs into various agents. Ghidra, the free decompiler from the NSA. GhidraMCP lets agents drive Ghidra. ida-pro-mcp connects agents to IDA Pro.

Mobile and Applications

jadx breaks Android APKs back into Java. Apktool unpacks and repacks. Frida hooks into an app while it is running. ILSpy decompiles .NET.

Binaries and Low Level

radare2, a reverse-engineering framework that lives in the terminal. x64dbg is a Windows debugger. ImHex is a hex editor with its own pattern language. angr is a symbolic execution engine.

Network and Runtime

mitmproxy sits in the middle and reads traffic. dnSpy debugs and modifies .NET applications. rizin is a fork of radare2. raddebugger comes from Epic Games.

Rebuilding and Verification

Two awesome lists: one collects 122 repositories and rates each one, and the other is maintained by the author of REA. REA workflows come with ready-made investigation prompts. The clean-room loop uses SPEC.md, an oracle, and checks, iterating repeatedly until they match.

The workflow is just one line: binary -> REA -> SPEC.md -> rebuild -> oracle -> retry.

Break that line apart, and the first four steps are nothing new. Decompiling, writing specs, rebuilding—reverse engineering has worked this way for decades. What agents change is speed, and the oracle at the end.

The oracle is the verifier. An agent saying the rebuild is correct does not count. You have to run test cases based on the original behavior; only if they pass does it count. In the DX-Ball case, REA recovered the calculation function for the sound-effect pan, rewrote it in C, ran it against 3,205 original x86 test cases, and the final reproduced compiled output matched the original function's 63 bytes exactly. That number is more convincing than any demo video.

Someone commented under the tweet that ghidra, jadx, and frida already cover most mobile apps, and REA's role is to be the glue that sticks three tools into one loop. That observation is more accurate than 'most dangerous.' Another commenter added something sensible too: to reach the point of being truly useful, a great deal of work remains.

Some people have already taken it apart and put it back together

codila wrote a complete course, from installation to case studies. A few numbers give a sense of the pace.

The Aegis validator has 3,077 classes; REA found how it generates 6-digit login codes, and after rebuilding, it passed all 133 test cases. For Super Mario Sunshine's native PC port, 365 agent hours, 1.73 billion tokens. For Tomba!'s static recompilation, the author had never done reverse engineering before and spent three weeks using Claude Code plus Ghidra. For Touhou Project's TH04, 697 functions, 696 exact matches, playable in 12 days.

The Notion case is a different use. REA traced how the copy feature starts from the page, passes through the IPC bridge, and finally lands in the system clipboard. This is not about copying Notion; it is about figuring out how many layers a daily operation actually goes through.

The legal side is unavoidable

After REA went viral, half the people were shouting piracy and the other half were shouting that software is dead. On All-In, Chamath said someone had decompiled Adobe's entire suite, and that video was slapped down by X's Community Note: those open-source alternatives were clean-room rewrites, starting from public specifications and observable behavior, without using Adobe's code or assets.

Clean room is a forty-year-old approach. One team studies the original product and writes down only behavior, without touching the code. Another team builds something new based only on that description and never sees the original code from start to finish. Compaq used this method in the early 1980s to redo IBM's BIOS, spending about one million dollars, and only then did the 'IBM-compatible PC' category exist.

The courts' attitude is also on record. In Sega v. Accolade in 1992, disassembling code could count as fair use if it was the only way to understand how it works. In Sony v. Connectix in 2000, Sony lost 0 to 3, and in the end the emulator contained not a single line of Sony code. On the other side is the 2011 PS3 jailbreak: GeoHot published the root key, settled the following April, and promised not to touch Sony products again.

The line is actually clear. Reading software on your own machine is learning. Rewriting your own implementation based on behavior is what the industry has always done. Copying someone else's code, cracking paid features, and publishing decompiled source code are the parts that get you sued.

The TradingView tweet is a counterexample. Someone said they used REA to get paid indicators for free; codila himself admitted in the article that building a terminal is fine, but using someone else's paid indicators for free is not.

What it cannot do

REA reads things on your machine. Code running on a company's servers was never sent to you, so it cannot touch a bank's backend. What comes out of decompilation is a reconstruction, not the original source code. Stripped C++ binaries are much harder than Unity's .NET. Some firmware and console targets run into the model's safety policies, and the agent simply refuses. Commercial tools like IDA, Hopper, and JEB require you to have your own license; REA does not provide licenses.

There are also several installation pitfalls. Node versions are picky: 23 and 25 are not on the supported list. Ghidra on Windows is still experimental read-only support. After installation, you need to fully quit the agent and reopen it; closing the window does not count. The star count is already six digits, and the README has a dedicated line of thanks, but versions iterate quickly, so it is best to run doctor once before installing.

Judgment

'Most dangerous' sounds more like a headline. A clean room with a forty-year history plus several open-source tools that have been used for many years—the only new thing is that an agent has been put into the investigation loop, able to ask its own questions, trace calls itself, write specs itself, and then use the oracle to slap itself in the face.

For developers, the usefulness of this setup is not in getting things for free. You have an internal system that has been used for three years, lacks documentation, and whose original author has left, or a third-party library with weird behavior that you must remain compatible with; tools like REA can take it apart into something readable. That scenario is not cool, but it is real.

For ordinary users, what you can do is more down-to-earth. Look at what that 'free signal' app is actually reading, or what is inside that 113 GB fake GTA 6 installer. Reverse engineering has always been for this.

Karpathy retweeted an old tweet saying that the gap in people's understanding of AI capabilities is widening, and roughly 600 million people are still stuck with the impression of free ChatGPT. This gap will show up in reverse engineering first. One side is still discussing whether it can be done; the other side is counting how many test cases the oracle has passed.

What is truly dangerous is not those 20 repositories. It is the software on your computer that assumes you will not look inside.