How to Use REA to Reverse Engineer Any App in Minutes

Summary

The video demonstrates REA (Reverse Engineer Anything), an open-source MCP server that lets AI coding agents inspect software and explain how its features work. Rather than replacing traditional reverse-engineering tools, REA connects agents such as Claude Code, Codex, Cursor, and Gemini CLI to tools including Ghidra, IDA, and Hopper, as well as readers for JavaScript/Electron apps, .NET programs, Android apps, and websites.

Reverse engineering means analyzing a finished program to infer how it works. REA provides an AI agent with findings, supporting evidence from files, and explicit limitations—so the agent can investigate further or implement a feature based on what it learned. Analysis runs locally, though the AI provider’s data policies still apply to results sent to the agent.

Installation and test

The walkthrough uses Claude Code and the open-source Windows screenshot tool ShareX:

1. Find the official REA repository and check that it is authentic. The presenter warns that viral projects may attract fake repositories or installers.
2. Open Claude Code in a new, empty folder.
3. Install REA using the README’s npm command, npx rea-agents setup. The presenter first asks for a dry-run plan, then approves changes to Claude Code’s settings and installation of REA’s usage instructions.
4. Restart Claude Code to load the new tools, or use REA’s command-line interface.
5. Analyze ShareX and ask Claude to investigate its capture and editing features and build a small web version.

ShareX is a .NET 9 application organized into libraries. REA’s detailed .NET reader hit a 64 MB limit on the large capture and image-editor libraries and reported that limitation rather than guessing. It could still identify available windows and features, and it successfully analyzed the Image Beautifier in another library.

What REA found and what was built

REA identified Image Beautifier’s settings, including margins, padding, smart padding, rounded corners, shadow controls, and background choices: gradient, solid color, image, desktop, or transparent. It also traced the order of operations:

1. Smart padding trims empty borders and selects a background color.
2. Padding is added.
3. Corners are rounded.
4. Margin is applied.
5. Shadow is added.
6. The background is applied.

REA revealed the call sequence but not the low-level pixel calculations inside the graphics library, such as the exact shadow-blurring method. Claude wrote those details from scratch. The presenter emphasizes that the feature’s structure came from evidence, while some implementation details were newly written.

The resulting prototype, MiniShot, is a single-page web app. It supports region capture, annotations (including arrows, text, numbered steps, highlighting, and pixelation), the analyzed beautifier options, and PNG or clipboard export. The presenter reports roughly four minutes of analysis and three more minutes to produce a working first version.

MiniShot is explicitly not a ShareX replacement. It lacks many of ShareX’s capabilities, such as uploads, recording, scrolling capture, text recognition, and workflows.

Assessment and cautions

The video argues that REA’s value is better understood as a way to learn from software and build focused tools for personal needs—not as a shortcut to clone and sell existing apps. The presenter recommends examining software you own or are authorized to inspect, respecting licenses, and distinguishing inspiration from copying protected code, designs, or assets.

The legal discussion is general rather than legal advice. The presenter says legality depends on jurisdiction and software licenses, and cites lawful purposes such as security research, education, interoperability, preservation, and authorized analysis. The project’s stated exclusions include breaking copy protection or license checks, creating game cheats, and copying proprietary code or assets.

Key guide covered: locating the official repository, installing REA in Claude Code, analyzing a .NET app, interpreting evidence and limitations, and using the findings to build a small, feature-focused prototype.

Main speakers and sources

• Wiredeep presenter/narrator: Explains reverse engineering, demonstrates the installation and ShareX test, and offers the legal and practical assessment.
• REA project: Cited as the source of the tool, its README, installation instructions, and stated usage limitations.
• ShareX: The open-source application examined in the demonstration.