Anthropic Updates Claude Opus 5.5 to Prevent Game Cloning
Anthropic has updated Claude Opus 5.5 to “steer it away” from letting users clone other developers’ games, after weeks of Steam being overrun with AI slop and outcries from the game development community.
In an update spotted by X user Chasm (via Game Developer) Anthropic added a new rule to Claude Code’s “Rules”. Listed under “tengu_heron_brook”, the rule reads, “Do build original games, games in a genre, and games from the user’s own designs and assets. Do not build a recreation of a specific existing game, even if it is renamed or called original.”
The addition was later confirmed by Addy Osmani, a member of Anthropic’s technical staff. In a response to Chasm’s post, Osmani stated, “We added two sentences to Claude Code’s prompt on Opus 5.5 to steer it away from recreating someone else’s specific game because using Claude to infringe IP is against our usage policy.”
Osmani added that “original games, genre games, and games built from your own design are meant to keep working. We’ll continue to iterate to ensure that we’re striking the right balance. In the meantime, if Claude turns down something that’s yours, send it my way.”
Opus 5.5 has proved adept at reverse engineering code, causing all manner of disruption within the games industry. The effects range from rapid decompiling of old console games to the PS5 being jailbroken.
Anthropic’s latest change arrives in the wake of multiple reports from game developers that their games and demos have been flagrantly copied with the aid of AI. This has led several studios to cancel planned public demos of their games for fear that the code in those demos will be reverse engineered and used to create AI clones.
This all occurred within the broader issue of Steam witnessing a massive influx of low-effort, vibe-coded games, many of which are heavy imitations or direct copies of existing titles. While low effort game clones are not a new issue within the games industry, the most recent Steam Next Fest saw the number of showcased demos double over the previous event, with AI assisted games accounting for most of that increase.
Valve itself has admitted that Steam has a problem with AI slop. But the company is reluctant to resolve the issue by simply banning AI coding tools. At Steam’s Indie Connect event last week, Valve’s Tom Giardino explained that Valve doesn’t want “to be gatekeepers telling developers which tools they should or shouldn’t use.”
As for what Valve does plan to do about the problem, Giardino didn’t have a specific answer, only that “making Steam a smarter and more dynamic platform is the starting point of our philosophy.” In the meantime, he suggested that developers make their games harder to copy, stating “you need to keep growing your game by adding features, personality and creativity that stem from your own perspective.”
While it’s true that the games being cloned are often small and not especially complex, it’s worth pointing out that many of the most important games released in the last few years are relatively simple designs. Games like Vampire Survivors, Balatro and Peak are all built upon elementary concepts. And yes, those games have spawned endless imitators. But it’s one thing to riff on their ideas with your own design, quite another to lift their codebase wholesale.
