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Reverse-engineer a feature with Claude Code: REA setup + 3 prompts

By Hammad Yousuf · 17 October 2026

REA (Reverse Engineer Anything) is a free, MIT-licensed open-source tool that connects Claude Code and other agents to reverse-engineering tools. You point it at an app on your own machine, ask how a feature works, and it returns the code paths it traced, the evidence behind each step, and the parts it could not confirm.

What it can inspect

  • Native desktop binaries (with Hopper, Ghidra or IDA installed)
  • JavaScript and Electron apps
  • Websites (with a Chrome-family browser)
  • Android APKs (with JADX and a JDK)
  • .NET assemblies, and more. The full table is in the README.

There is no iOS app support listed, so "any mobile app" is not accurate.

Setup (about 5 minutes)

  1. Install Node.js 22.19 or newer (the README lists 22.x ≥ 22.19, 24.x ≥ 24.11, or 26+).
  2. In a terminal, run:
    terminal
    npx rea-agents setup
  3. Choose Claude Code, review the proposed changes, and approve them. Setup adds REA's MCP server and workflow instructions.
  4. Restart Claude Code.
  5. Install links only from the official repository or rea.tools. The README warns that look-alike repositories exist.

The three prompts

Paste them into Claude Code in order. Replace the parts in square brackets.

1 · Map the feature

prompt 1 of 3
Use REA to investigate [app path or URL]. I own this app or am authorized to examine it. Explain how the [feature name] feature works from the user's click to the final output. For every step, show the evidence REA found and list anything you could not confirm.

2 · Extract the pattern, not the code

prompt 2 of 3
From that investigation, describe the underlying pattern in plain language: data flow, main components, and the key decisions. Do not reproduce the original code. Then list the 3 parts that would be hardest to build and why.

3 · Build my own version

prompt 3 of 3
Design an original implementation of this pattern for my project. My stack: [framework, language, database]. Give me a file-by-file plan, then implement the first file with tests. Keep it independent from the inspected app's code.

Sources checked

The facts on this page were checked against REA's official sources below. The tool changes fast, so treat the README as the final word.

  • REA is open source under the MIT licence; official repo morluto/rea. Source ↗
  • Install command is npx rea-agents setup; setup supports Claude Code and registers an MCP server. Source ↗
  • Supported targets include native binaries, JavaScript/Electron, websites, Android APKs, .NET; no iOS target listed. Source ↗
  • Requires Node.js 22.x >=22.19, 24.x >=24.11, or 26+. Source ↗
  • Project limits use to software you own or are authorized to examine. Source ↗
  • npm package rea-agents, MIT, version 6.5.0. Source ↗

About the video: the reel that sent you here uses an AI avatar of Hammad Yousuf.

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