Claude Code, Anthropic’s coding assistant, has been told to stop building copies of existing video games. A rule added to its system prompt in late October bars it from reproducing a specific game, even if the copy gets a new name or is passed off as original.
Anything that is not a copy still works: new games, games that follow a genre and projects built on the user’s own art and design. The change matters to people who have been asking AI tools to rebuild a favourite title as a browser project.
An X user posted the text on 30 October. According to that post, the rule reached Claude Code around 27 October and is pushed from Anthropic’s servers under an internal flag, so users cannot turn it off. The quoted line tells the model not to “build a recreation of a specific existing game, even if it is renamed or called original.”
Addy Osmani of Anthropic confirmed it the same day in his own post on X. The company added two sentences to the Claude Code prompt on Opus 5.5, he wrote, because infringing someone’s IP breaks its usage policy. He said Anthropic will keep adjusting the balance and asked people whose own projects get refused to send him examples.
A response to browser rebuilds
The move follows a wave of AI-assisted rebuilds of commercial games that run in a web page, with fan versions of Halo: Combat Evolved, Call of Duty: Modern Warfare 2 and Grand Theft Auto V among them. Publishers own the code and assets behind those titles, so a faithful copy is a copyright problem whatever it is called.
Anthropic already has copyright fights behind it. Last year it settled with authors who said their books trained its models, for $1.5 billion, and the estate of Elvis Presley has since sued the company as well.
Because the rule sits in the prompt and not in the model’s training, how strictly it bites will depend on how a request is phrased. Osmani’s invitation to send examples suggests Anthropic expects some wrong refusals.
