Anthropic’s Claude Code and Opus 5.5 now block video game cloning
Anthropic engineer Addy Osmani confirmed the change on October 30. The text also sits inside Claude Code version 2.1.314, while separate Opus 5.5 settings suggest the model can receive the guidance on its own. Independent tests found that Opus 5.5 still agreed to help with a decompilation and a static recompilation of Pokemon Diamond, treating both as different from rebuilding the game.
Because using Claude to infringe IP is against the company’s usage policy, he said the sentences were added to Claude Code’s prompt on Opus 5.5.
The rule was first spotted by an X user called chasm, who traced it to a flag named “tengu_heron_brook” that reached Claude Code around October 27. Anthropic has added a new rule to Claude Code that stops the AI coding tool from recreating existing video games, even if a user renames the copy or calls it original. The two-sentence instruction tells Claude to build original games, games in a genre and games from a user’s own designs and assets, but not a recreation of a specific title. Original games should keep working, he added, and anyone wrongly refused can send the case to him. There is reportedly no setting to switch it off. That is where the trouble starts. Developers report otherwise elsewhere. One filed a GitHub issue after Claude refused to help build board-wargame modules for paying customers, made from games those customers own.
A developer testing his own software found that switching to Opus 4.8 let his work continue, and a Reddit user said their account was suspended over Opus 5.5 and a reverse engineering tool, then reinstated. Reverse engineering tasks are also being refused. The rule also leaves open questions. A straight copy of Tetris would be blocked, but a game in the Tetris genre should pass. Where a mashup, such as Mario dropped into Elden Ring, falls is anyone’s guess. Claude is left to judge that on its own, with only two sentences to go on.