In a classic clean-room project, one team studies the original product and writes a specification of what it does. A second team, which has never seen the original code, builds new software from that specification alone. The separation is the evidence that nothing was copied, which is what lets the result be released under a different licence.
AI coding agents have made the approach cheap enough for one person to attempt across a whole product suite, as the ArtCraft alternatives to Adobe’s applications showed in October 2026. The legal protection is narrower than the name suggests. Copyright covers code, but patents and design rights can still apply to how a feature works or looks, and a model trained on public code makes it harder to prove that no original material crept in.
For an enterprise, the rule of thumb is simple: before adopting software described as a clean-room rebuild of a commercial product, ask your counsel about patents and trade dress, and keep a record of where the code came from.