Anthropic restricts Claude Code from recreating existing games via a server-side switch
Anthropic delivers rules to Claude Code via a server-side switch named tengu_heron_brook, prohibiting the recreation of specific existing games, even if renamed or claimed to be original, and there is no option to turn it off. The rules still allow original games, games in the same genre, and projects based on the user's own designs and assets. The author believes that at the implementation level, its weapon jailbreak classifier stack can be reused; the difficulty lies in the fact that copyright only protects a game's look and feel rather than its mechanics, so the detector needs to distinguish between the same genre and the same game.
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The original text provides the specific rule text and delivery method for this restriction, allowing readers to judge its actual impact on game-related generation requests.
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View original postANTHROPIC IS CRACKING DOWN ON VIDEO GAME REWRITES 🚨 Claude Code picked up a new rule around Oct 27, sent from Anthropic’s servers under a flag called "tengu_heron_brook". There’s no setting to turn it off. The full rule: “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.” Is this the end of game rewrites, modding and everything in between?
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ANTHROPIC IS CRACKING DOWN ON VIDEO GAME REWRITES 🚨 Claude Code picked up a new rule around Oct 27, sent from Anthropic’s servers under a flag called "tengu_heron_brook". There’s no setting to turn it off. The full rule: “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.” Is this the end of game rewrites, modding and everything in between?
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Anthropic is cracking down on video game clones.
Looks like the rule arrived through a server-side flag, “tengu_heron_brook”, so it reaches every session without an update and has no off switch.
The instruction still permits original games, games in a genre and projects built from a user’s own designs and assets.
Exact rule text: “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.”
To enforce the above rule it at scale, Anthropic can reuse the classifier stack it built for weapons jailbreaks: small models trained on a written rule list that read each request with its output, plus cheap probes on Claude’s internal activations that flag intent to copy a specific title.
Research tools go further, comparing code even after renaming, matching runtime behaviour and sprites, and measuring “distance” between game designs. i.e. measuring distance between them with concept vectors.
The hard part is legal: copyright protects a game’s look and feel, not its mechanics, so every detector has to separate “same genre” from “same game,” and that is where false refusals will come from.