Anthropic has updated its AI coding tool Claude Code so it stops building clones of existing video games.
The change was first spotted by X user Chasm, who said it was pushed to Claude Code on October 27. Listed under the internal name “tengu_heron_brook,” the rule tells the model to build “original games, games in a genre, and games from the user’s own designs and assets,” but not “a recreation of a specific existing game, even if it is renamed or called original.” According to Chasm, users cannot switch it off.
Anthropic member of technical staff Addy Osmani later confirmed the update on X, saying the company had “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.”
“Original games, genre games, and games built from your own designs and assets are meant to keep working,” Osmani added. “We’ll continue to iterate to ensure we’re striking the right balance.”
As Game Developer points out, it’s not clear how effective the rule will be, as safety restrictions on AI models can be bypassed with carefully worded prompts, and there’s no obvious way for Claude to verify whether a user actually owns the game design or assets they’re working from.
The update also comes as developers grow increasingly concerned about how AI tools can be misused to clone games. Digital Sun recently delayed a public playtest of ReVamp over fears its demo could be fed into an AI tool, while Valve has faced pressure to explain how it will stop AI-made clones from crowding out original games on Steam.