ArtCraft didn’t clone Adobe with REA: Photoshop, Lightroom, Word and the other apps were rewritten from scratch with AI, using a clean-room approach

No, they didn’t clone Adobe with REA.

This rumor has been going around since Sunday evening, and I’m seeing it in the comments on my videos too. But it’s wrong, and the reason is more interesting than the rumor itself.

What ArtCraft is: Adobe and Office rewritten from scratch in Rust

Let’s start with the facts. Brandon Thomas, the developer behind the ArtCraft project, has released free, open source versions of Photoshop, Premiere, Illustrator, Lightroom, After Effects, InDesign and Acrobat. A few days later, Word, Excel and PowerPoint followed. He wrote them from scratch in Rust, with Claude as his main tool for the code.

The seven Adobe apps were covered by PetaPixel on 7 October 2026; the Word, Excel and PowerPoint clones are called WordCraft, GridCraft and DeckCraft and live in ArtCraft’s GitHub organization.

REA and ArtCraft: two projects with nothing to do with each other

REA, on the other hand, is a different project, released at roughly the same time. It’s built for reverse engineering, meaning looking inside an existing program, decompiling it and working out how it was written. The two stories got lumped together, but they have nothing to do with each other.

What clean-room means: public specs and observation

I checked their repositories on GitHub. There’s no reference to REA anywhere in the code. Every app describes itself as "clean-room", meaning built from just two sources.

The PhotoCraft README says “implemented from public specs and observed behaviour only”, and the WordCraft one says “built from public specifications and observation”.

The first is public specifications. Adobe has published the one for the PSD format, PDF is an ISO standard, and video codecs have international specifications. Anyone rewriting Photoshop already knows exactly how a .psd file is structured, without having to open Photoshop.

The two specifications: Adobe Photoshop File Formats Specification and ISO 32000-2:2020 (PDF 2.0).

The second is observation. You use the original program the way a user would, watch what it does, and write your own code until the result matches.

Why LightCraft forbids reading Adobe’s programs

In fact, their internal rules point in the opposite direction from REA. The rules for LightCraft, the Lightroom clone, explicitly forbid reading Adobe’s programs. It’s not a detail, it’s a legal choice. If you can show you never looked at the original code, nobody can accuse you of copying it. It’s the same technique that let Compaq recreate IBM’s BIOS in the ’80s and build the first compatible PCs.

The rule is in LightCraft’s AGENTS.md: “Clean-room. Never read/disassemble anything inside Adobe app bundles”. On the Compaq case, see the Clean-room design entry.

The real news: one person with AI, in place of entire teams

So the real news isn’t "AI took Adobe apart". It’s that one person, with AI, rewrote from scratch software that took entire teams years to build. And it’s still in alpha. Word, for example, is about 60% rebuilt, according to the authors themselves.

The WordCraft README describes the project as alpha and estimates it is “about 60% of the way to replacing all of Word for real work”.

It’s the same ratio of one person to AI agents that I work with in AI-assisted software development for companies.

Reverse engineering and rewriting from specifications are two different paths. Mixing them up leads people to think any software can now be copied at the push of a button. That’s not the case, but what’s happening is still huge.