Anthropic updates Claude to stop it from cloning existing games

Anthropic has updated Claude to stop it from building clones of existing games, after AI-generated knockoffs flooded Steam this month. PC Gamer describes the change as Anthropic moving to "steer it away" from letting users copy other games.

The new rule showed up in Claude Code around Oct 27, according to a post from X user chasm, who says it's delivered from Anthropic's servers under a flag called "tengu_heron_brook" and can't be switched off.

Per that post, the rule reads: "Do build original games, games in a genre, and games from the user’s own designs and assets. Don’t build a recreation of a specific existing game, even if it is renamed or called original."

So making your own roguelike or a game in a familiar genre is still allowed. Asking for a straight copy of a specific game, with a new name slapped on, isn't.

The backdrop is Steam Next Fest. Players complained their feeds were packed with low-effort clones, including copies of games that had only just released their own demos.

That hit developers directly. Some, including Drunken Goddess Reflux developer Alliance Arts and Who You, canceled Steam demo plans in favor of private playtests.

Valve responded too, saying it would be "thinking about how to solve this problem." It hasn't announced a fix yet.

chasm's post also asked whether this spells the end for game rewrites and modding. Anthropic hasn't said how the rule treats those projects, so that line between a clone and a fan rewrite is still unclear.