Anthropic has officially updated its AI language model, Claude Opus 5.5, introducing a specific rule designed to steer the technology away from letting users clone existing video games. The move comes after weeks of growing outcry from the game development community, as digital storefronts like Steam have become increasingly overrun with low-effort, AI-generated games and direct imitations of established titles.
The change was first spotted by X user Chasm, who highlighted a new addition to Claude Code’s internal instructions. Listed under the rule identifier "tengu_heron_brook," the updated text explicitly instructs the AI: "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."
Shortly after the discovery, Addy Osmani, a member of Anthropic’s technical staff, confirmed the update on social media. Responding to Chasm’s post, Osmani explained the reasoning behind the sudden adjustment to the model’s behavior.
"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 stated. He further reassured developers that legitimate workflows would remain unaffected, adding that original games, genre-inspired projects, and games built from personal designs are still meant to function as intended.
"We’ll continue to iterate to ensure that we’re striking the right balance," Osmani continued. "In the meantime, if Claude turns down something that’s yours, send it my way."
The update arrives at a critical juncture for the gaming industry. Opus 5.5 has demonstrated an advanced ability to reverse-engineer code, triggering widespread disruption across various technological sectors. Beyond video game development, the model’s capabilities have facilitated rapid decompiling of legacy console software and even contributed to the jailbreaking of current-generation hardware like the PlayStation 5.
Within the gaming landscape, however, these reverse-engineering capabilities have sparked a severe defensive reaction. Numerous independent game developers have reported that their public demos and released titles have been flagrantly copied with the assistance of artificial intelligence tools. The threat of intellectual property theft has become so pronounced that several development studios have taken drastic measures, including canceling planned public playtests and demos out of fear that their underlying code will be harvested and replicated by AI-assisted competitors.
This situation is compounded by a broader, ongoing issue on platforms like Steam, which has seen an enormous influx of low-effort releases often referred to as "vibe-coded" games. These titles frequently rely on heavy imitations or direct copies of existing successful games. While clone titles are by no means a new phenomenon in the history of interactive entertainment, the problem has scaled dramatically with the widespread availability of generative AI coding assistants. During the most recent Steam Next Fest, the number of showcased demos doubled compared to previous events, with AI-assisted submissions driving the vast majority of that unprecedented growth.
Platform holders are now grappling with how to address the crisis without stifling innovation or overstepping their bounds as marketplace operators. Valve itself has openly acknowledged that Steam faces a significant problem regarding AI-generated slop and rampant cloning. Nevertheless, the company has expressed clear reluctance to resolve the issue simply by banning AI-assisted coding tools outright.
Speaking at Steam’s Indie Connect event, Valve representative Tom Giardino addressed the dilemma, explaining that the company does not want to act as a gatekeeper telling developers which tools they should or should not use in their creative pipelines. When pressed on concrete solutions, Giardino did not offer an immediate or restrictive enforcement policy. Instead, he suggested that making Steam a smarter and more dynamic platform serves as the foundational starting point for the company’s philosophy. In the interim, Giardino advised independent developers to focus on making their games more difficult to copy by continuously adding unique features, distinctive personality, and creative elements rooted in their own personal perspectives.
While many of the titles targeted by AI cloning operations tend to be smaller, mechanically straightforward projects, industry observers note that simplicity does not equate to a lack of value or originality. Several of the most critically acclaimed and commercially successful games released in recent years—such as Vampire Survivors, Balatro, and Peak—are built upon deceptively elementary concepts. Unsurprisingly, those breakout hits have spawned countless legitimate genre imitators. Yet industry veterans emphasize a fundamental distinction between taking structural inspiration from a genre framework and lifting an entire codebase wholesale through automated reverse engineering.
Anthropic’s implementation of the "tengu_heron_brook" rule represents one of the first direct interventions by a major AI developer to curb intellectual property infringement within the indie game sector. Whether these tightened prompt guidelines and ongoing platform-side adjustments will successfully stem the tide of AI-driven game cloning remains to be seen as the industry continues to navigate the rapid evolution of generative technology.
