Special · Reverse engineering

AI agents look inside apps: the REA craze and where the line is

REA (Reverse Engineer Anything), an open-source tool that lets AI agents take apart programs without source code, gathered nearly 290,000 GitHub stars in about two weeks. Here is what it does, what people who tried it said, and how far is too far.

1. What REA is: a reverse-engineering tool for coding agents

   REA is an MCP (Model Context Protocol) server for coding agents such as Claude Code, Codex, Cursor and Gemini CLI. Its README says it lets agents inspect native binaries, JavaScript and Electron apps, .NET assemblies and websites without source code. Analysis runs locally, and it is MIT-licensed.

2. How to use it: one command, works with Ghidra, IDA and Hopper

   Per the official site, run npx rea-agents@latest setup, approve the setup plan and restart your agent. Native analysis uses an existing Hopper, Ghidra or IDA install, and setup can install Hopper with approval. Static JavaScript analysis needs no native engine.

3. Official demos: why Calculator says 200 + 10% = 220, and the dino game's top speed of 13

   rea.tools shows REA explaining why Windows Calculator returns 220 for 200 + 10%: it computes 10% of 200 as 20, then adds it. For Chrome's dinosaur game it found that speed starts at 6 and rises slightly each update while below 13, reaching 10.0 after 4,000 updates and 13.0 after 10,000.

4. @AravSrinivas · X ↗

   How far it spread: from 40 stars to nearly 290,000 in about two weeks

   As of 6:31 a.m. KST on Oct 17 the repo had 289,654 GitHub stars and 72,908 forks. It had about 40 stars on Oct 2, passed 96,000 on Oct 11 and 190,000 on Oct 13, which is why articles cite figures from 100,000 to 229,000. Perplexity added REA as a skill in Computer on Oct 16, free through the end of the month. On YouTube, Nick Saraev's test video passed 1.27 million views and a Korean video by Coding Apple passed 570,000.

5. Mixed@yuhasbeentaken · X ↗

   "Vanilla Opus actually finished first"

   A user who spent more than 12 hours with REA said that when rebuilding the same app with and without it, vanilla Opus finished first. REA still produced a complete version with zoom, sharing, drawing, rotation, annotations and saving, and the bigger shift is agents operating specialist tools themselves, the user wrote.

6. NegativeKorben · korben.info ↗

   "No better than asking Claude to install Ghidra"

   French tech blogger Korben tested four tasks with Claude Code, Opus 5.5, REA 6.4.0 and Ghidra. Patching a binary and cloning a Mac app worked, but every task also succeeded without REA with little time difference. He concluded it does no better than a Claude told to install Ghidra, and warned about prompt injection hidden in booby-trapped binaries.

7. NegativeAISeeKing · YouTube ↗

   "The most useless thing I've ever tried"

   YouTube channel AISeeKing argued that current models already decompile and test with base tools, and that REA wraps the same tools in one more layer. It pointed to roughly 460,000 lines of TypeScript, more than 200 tools, and a 422-byte input that produced 759 KB of MCP output.

8. Positive@dorukyalcinsoy · X ↗

   An iPad vertical-monitor app built at the airport

   A Turkish developer said that while waiting for a flight he used Claude Code and REA to copy the paid app BetterDisplay and make an app that turns an iPad into a vertical second screen. He wrote that he copied a paid app for free, and released the result as open source.

9. 'AI copied every Adobe app'? A separate project from REA

   The hype was fueled by Brandon Thomas's ArtCraft apps. The PhotoCraft repo, a Photoshop rebuilt in Rust, passed 64,000 stars. CineD reported that Thomas said he built them with Claude Opus 5.5, and the repo calls itself a clean-room reimplementation from public specs and observed behaviour. Claims that REA copied Adobe have no support; DevelopersDigest noted nothing in REA's README says it produced ArtCraft. CineD said the clean-room claim has not been independently verified and Adobe has not commented.

10. Where the line is: "an app's license may restrict reverse engineering"

    REA's disclaimer says it will not help copy proprietary software or reproduce protected code and assets, or bypass DRM, license checks and anti-cheat, and that reverse engineering may be restricted by jurisdiction or by the license of the software analyzed. Prof. Andres Guadamuz of the University of Sussex told Al Jazeera it is unknown whether ArtCraft's claimed clean-room process stands up to scrutiny. KuCoin News noted US case law has upheld license clauses banning reverse engineering, while in the EU clauses that bar reverse engineering for interoperability are void.