Anthropic Steers Claude Code Away From Cloning Existing Video Games

An X user called Chasm first noticed the change. According to Game Developer, Chasm said the update to Claude Code's rules was pushed around October 27 and that users cannot switch it off. The new prompt text, as quoted by Game Developer and PCWorld, tells the model: "Do build original games, games in a genre, and games from the user's own designs and assets." It also says: "Do not build a recreation of a specific existing game, even if it is renamed or called original."

When Game Developer asked Anthropic about it, a spokesperson pointed to a post on X by Addy Osmani, a member of the company's technical staff. Osmani wrote that Anthropic "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 its usage policy. He said that "original games, genre games, and games built from your own designs and assets are meant to keep working," and asked developers to send him cases where Claude turns down their own work.

Why It Happened Now

The change follows weeks in which people used AI models to reverse-engineer software. PCWorld reported that the usual method is to have the model decompile a game's ROM or binary to recover readable source code. Galleries online show games that Claude reportedly re-engineered, including Diablo II, Grand Theft Auto 2, The Legend of Zelda: Link to the Past and Harvest Moon. GitHub projects have also appeared with step-by-step instructions and "skills" for rebuilding existing titles with AI.

Game studios have reacted. According to Game Developer, Digital Sun Games cancelled a public playtest of its upcoming game ReVamp because it feared someone could feed the demo into an AI tool and clone it. The developer of Moonlighter also delayed a public playtest of its next game over the same concern. Developers have pressed Valve on how it will keep AI clones off Steam, and PC Gamer tied Anthropic's change to weeks in which the store was flooded with low-quality AI-made games.

Disputed Scope

Tom's Hardware reported claims from several users that Claude Code or Opus 5.5 now also blocks reverse-engineering tasks that look harmless. PCWorld said Claude has reportedly started refusing prompts for removing unwanted software from smart TVs, which was a popular use. Anthropic has not confirmed any wider limit on reverse engineering. Osmani's public comments cover recreating specific games only.

Game Developer raised doubts about how well the rule will work. Documented jailbreak techniques could let users get around it. It is also unclear how the software would decide whether a user owns a game idea or its assets. Users replying to Chasm's post said people who want to make clones could switch to open-weight models, which have no such limits.

The episode shows a growing problem for AI labs. Coding agents that can rebuild software from compiled files are commercially valuable, but they expose model providers to intellectual property disputes. Anthropic chose a light-touch prompt change rather than a hard technical block and says it will keep adjusting it. "We'll continue to iterate to ensure we're striking the right balance," Osmani wrote, according to Game Developer.