Reverse Engineer Anything (REA): What It Is & How to Use It

What is Reverse Engineer Anything (REA)?

Reverse Engineer Anything (REA) is a free, open-source toolkit that lets AI coding agents — Claude Code, Codex, Cursor, Gemini CLI, Grok Build — inspect software without having its source code: native binaries, Electron apps, JavaScript bundles, .NET programs and live websites. It ships as an MCP server plus a command-line tool under an MIT license, and has earned more than 110,000 stars on GitHub (github.com/morluto/rea).

Reverse engineering used to mean an expert spending weeks in a disassembler reading assembly by eye. REA packages that expertise as tools your AI agent can call: point it at an app, ask how a feature works, and the agent runs the analysis, cites the evidence it found, and states what remains uncertain — instead of guessing.

How REA works

REA has two halves, and you can use either or both:

• MCP server — exposes the analysis tools to your coding agent, so Claude Code or Cursor can decide what to inspect and iterate like a human analyst would.
• CLI — runs the same analyses from the terminal or scripts, no agent required.

Two design choices make the output trustworthy. First, analysis runs locally on your machine — nothing is uploaded. Second, every report includes evidence and stated limitations, so conclusions are verifiable rather than plausible-sounding. The rigor bar is high: in the project's DX-Ball case study, the agent reconstructed the 1996 game from its binary well enough that all 3,205 original x86 test cases passed and all 63 compiled function bytes were reproduced exactly.

How to install REA

You need Node.js 22.x (22.19 or newer), 24.x (24.11 or newer) or 26+, with npm. One command does the wiring:

npx rea-agents@latest setup

1. Run the setup command

npx rea-agents@latest setup configures the MCP server integration for the agent you use.

2. Pick your agent

The officially supported list is Claude Code, Codex, Cursor, Gemini CLI and Grok Build — and any agent that can connect to a local MCP server works too.

3. For native binaries: approve an engine

Native targets are analyzed through Hopper, Ghidra or IDA. With your approval, setup can install Hopper for you. Static analysis of JavaScript and .NET apps needs no engine at all.

Using the REA CLI from the terminal

For one-off analysis you can skip the agent entirely. Install globally and ask for help:

npm install --global rea-agents
rea --help

Or run a one-shot analysis without installing anything (pass an absolute path to the app):

npx -y rea-agents@latest analyze-javascript-application /absolute/path/to/app --json

The JavaScript/Electron analyzer returns a JSON report covering modules, imports, source maps, routes, IPC channels and native add-on relationships — the map an agent (or you) needs to answer questions about code nobody has the source for.

Use case: reverse-engineering an Electron app

Electron apps are the sweet spot: the entire business logic ships as JavaScript bundles, which REA analyzes statically with no disassembler required. The project's own case study walks through the Notion desktop app's clipboard bridge, tracing how copied text travels from the renderer to the OS clipboard.

A typical question an agent can then answer: where a setting gets persisted, which IPC channel a feature uses, or which native add-on a bundled module talks to — each answer backed by the file-level evidence from the report. The Hacker News discussion and this Cyber Security News review cover more real-world runs.

What can REA analyze?

A quick map of supported targets and what each one needs:

REA video review

Prefer watching? This hands-on review runs REA against real binaries and shows what the agent actually finds:

Is REA free, safe, and legal?

• Free — REA is MIT-licensed open source. The toolkit costs nothing; you pay only for your AI agent (and any commercial disassembler license you choose).
• Safe — analysis runs locally, and your app is never uploaded anywhere.
• Legal — reverse engineering can be restricted by software licenses and local law. The REA documentation stresses lawful use, and the responsibility for staying inside it is yours.

One note: this is an independent guide — we are not affiliated with the REA project. And since you are on an OC-maker site: if you came for the creative kind of engineering, the free AI OC generator designs characters in about 10 seconds, and the how to make an OC guide covers the workflow.

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