The backdrop: WordCraft and the ArtCraft clones
PCWorld's Mark Hachman frames the story around open-source replications of Microsoft Word, Excel, and PowerPoint, built with AI by a developer named Brandon Thomas. The apps are WordCraft, GridCraft and DeckCraft. They are built in Rust and offer familiar features such as the Ribbon interface, document styles, tables, track changes, comments, spelling and grammar checks, and mail merge. They also read and write the real Microsoft file formats (DOCX, XLSX and PPTX) and run on macOS, Windows and Linux.
Thomas calls them clean-room implementations. He says he did not decompile the original apps or copy Adobe's source code, which is the claim he made about the Adobe clones that came first. Coverage describes the approach as working from the public ECMA-376 and ISO/IEC 29500 format standards and from watching how Microsoft's programs behave, rather than from Microsoft's code.
These are rough, and the project says so itself. ArtCraft's self-reported figures put WordCraft at 97% of ribbon commands and about 60% readiness for real work. Earlier snapshots from other outlets showed lower command coverage, which suggests the numbers move quickly. Treat all of them as the developer's own claims, not independent testing.
Two caveats matter for what follows:
- "Clean-room" is the creator's description. It is not a legal finding.
- Nothing in the reporting says Microsoft has sued, threatened or approved WordCraft.
What the experts told PCWorld
The headline question is whether you can safely do the same thing yourself. The experts PCWorld quoted say private experimentation is low risk. They also say the risk rises when you distribute or sell the result.
- Mitch Stoltz is the Electronic Frontier Foundation's competition and IP litigation director. He said legal risk is low for private experiments and personal tools, but "increases quickly" if you distribute or sell the output. (PCWorld printed his full statement; I've quoted only a fragment of the wording.)
- Clark Asay is a Brigham Young University law professor. He doubts anyone would discover or sue over private use. He did add that a utility could technically still infringe a patent.
- Jonathan Band, an intellectual-property lawyer, warned about a specific failure mode. If you ask an AI to reverse engineer a particular program, it may copy code or the program's "structure, sequence, and organization", which may be protected expression. He also said the line between protected expression and unprotectable ideas is far from clear.
The headline takeaway is that your risk is not set by the fact that you used AI. It is set by what you tell the model to imitate and what you do with the result.
The prompt is the problem
PCWorld's practical argument is that LLMs are precise but lazy. If you tell a model to clone a named product, it may take shortcuts. Asay's concern is that the AI will lean on the named app to work out how to copy it more efficiently.
PCWorld's own worked example is a voice transcription app compared with Otter.ai, not Word. It does not document a specific "make me a Word clone" prompt, and it does not report a lawsuit over one.
Safer prompting, per the reporting
- Describe functions, not brands. Ask for what the app does, such as capture audio, transcribe it and export text. Don't call it a clone or a "reverse-engineered version" of a named product.
- Don't paste in screenshots of the original. Stoltz said including screenshots could make the model more likely to copy copyrightable elements, because user interfaces can be covered by copyright. Asay agreed it raises risk.
- Design your own interface. PCWorld admits this is tedious, since aligning and coloring one button can take far longer than defining features. That is exactly why it's tempting to tell the AI to match a commercial app.
- Keep it personal. Sharing with friends is one thing and selling is another.
PCWorld's framing of "clean room" is also worth noting. In traditional practice, one team documents what software does and a separate team writes new code from that description. In vibe coding, the user plays the first team. Stoltz said duplicating function this way isn't illegal and has driven a lot of innovation.
Where the law gets murky
Cornell's Legal Information Institute summarizes the landscape this way: reverse engineering is not categorically legal or illegal. The citation tag above is a placeholder, so treat this as general background rather than a quote. In plain terms, liability can arise from several separate areas of law:
- Copyright. Courts have sometimes treated intermediate copying during reverse engineering as fair use. The Ninth Circuit's Sega v. Accolade decision is the standard example, where the copying was needed to reach unprotected functional elements for compatibility.
- Contract. Terms of service may forbid reverse engineering. Whether that is enforceable depends on the jurisdiction and the circumstances. PCWorld notes that subscription terms may try to block it.
- Patents. Independent invention is not a defense. Asay said it doesn't matter how you came up with the app if a patent's claims cover something in it.
- Trade dress and look and feel. This is the interface issue the experts flagged.
- Trade secrets and anti-circumvention. Cornell says these can come into play when access is improper or involves circumvention.
The Supreme Court's Google v. Oracle decision is often cited here. The Court assumed the Java API code was copyrightable without deciding it, and then found fair use. It is fact-specific and not a blanket license to copy.
The "one room" problem
Declic Media examined the ArtCraft Adobe repositories and raised a point that applies to any vibe coder. A traditional clean room separates the people who observe the original from the people who write the code. That wall is mostly about evidence, because it shows the writers never had the original in front of them.
Declic reported that ArtCraft's published guidelines don't describe such a partition. Legal scholar Andres Guadamuz said that is where the problem lies if the same developer observes the software, writes the specification and then prompts the model. There is also a question nobody can check from outside: what the model saw during training. PCWorld calls it possible but unlikely that a model was trained on a commercial app's source code.
As of October 13, Declic found no public Adobe action and no takedown notice against the project in GitHub's public registry. That is a time-bounded observation about Adobe. It is not a clearance, and it says nothing about Microsoft. PCWorld adds that the law firm Falcon, Rappaport and Berkman thinks Adobe probably won't sue. The firm's reasoning is that these projects are mostly free and individual-run, so there is little to recover and a real risk of public backlash. It also says incumbents may be wary of testing an untried theory and ending up with a bad precedent.
What it means for Windows users and IT admins
- Hobbyists. Keep it personal, prompt for function, and design your own UI. The experts consulted see little real-world risk at that scale.
- Anyone considering distribution. The risk profile changes. Patents, contract terms and interface copying are separate concerns, and a commercial release is the point where a lawyer should get involved. This article is general information, mostly about U.S. law, and is not legal advice.
- IT admins. Free Office-format clones may appear on endpoints. They are alpha-grade by the developer's own account, with open work on real-world DOCX validation, pagination and stability. Treat them as unvetted software under your normal application policies. Don't assume file fidelity with Word, and test before anyone relies on one for production documents.
- The bigger trend. Replicating a program's surface now costs very little. Declic notes that the harder part, which is compatibility, plug-ins and support, is what commercial vendors really sell. Whether that holds for Microsoft 365 is an open question. Microsoft has not been reported to have commented.
Bottom line
Vibe-coding your own tool is very unlikely to land you in court. The line moves when you name a commercial product as the target, hand the AI its screenshots, or start selling the result. PCWorld's advice boils down to this: describe what you want, not what you're copying, and draw your own buttons.