Ask Claude Code to rebuild a well-known game with the serial numbers filed off, and it is now supposed to refuse. Anthropic’s coding assistant picked up the rule around 27 October, and it arrived from Anthropic’s servers, so users cannot turn it off.
The wording that circulated among users is short: “Don’t build a recreation of a specific existing game, even if it is renamed or called original.” An X user, Chasm, found it tied to an internal flag called tengu_heron_brook and posted it on 30 October.
What still works
The same instruction tells the model to go ahead with original games, genre games and projects based on the user’s own art and design. Anthropic’s Addy Osmani said the line went into the instructions Claude Code gives Opus 5.5, because copying someone else’s game breaks the company’s usage policy, and that Anthropic will keep adjusting it. His full comment is in IGN’s report.
Anthropic has not given a trigger. The change does follow this month’s anger over AI-made lookalikes crowding Steam during Next Fest, where some studios dropped public demos in response.
A wargame project caught in it
A GitHub issue dated 30 October describes the downside. The developer behind Conflict Simulations LLC says Claude Code stopped helping with custom digital board-wargame modules ordered by paying customers, who own the matching physical games. The code is original and the customers supply the materials, but the publishers have not licensed the work, as Wccftech summarises it.
Complaints about reverse-engineering tasks have also appeared, though nothing ties them to this line. Modders and preservationists who use AI tools for performance patches and ports are the ones to watch, since a refusal there is harder to predict than a flat ban.
Anthropic has not said how Claude Code decides what counts as a recreation, and Osmani is asking people who were wrongly refused to get in touch.
