Claude will not recreate a specific existing video game

Anthropic has added an instruction telling Claude not to recreate a specific existing video game, according to the users who spotted it and an Anthropic staffer who confirmed it on October 30.

The rule reaches anyone who has leaned on Claude Code for game work. In the week since it surfaced, the Claude Code GitHub tracker has filled with reports of refusals that developers say go past clones, to replicating a single game mechanic and patching a tabletop-style game.

According to Game Developer, X user Chasm found the rule around October 27 under a server-delivered configuration flag called tengu_heron_brook. The text 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." XDA Developers said it verified the same instruction inside version 2.1.314 of the Claude Code binary.

Anthropic's Addy Osmani, a member of its technical staff, confirmed the change in a post on X the company pointed Game Developer to when asked for comment. "We added two sentences to Claude Code's prompt on Opus 5.5 to steer it away from recreating someone else's specific game because using Claude to infringe IP is against our usage policy," Osmani wrote. "Original games, genre games, and games built from your own designs and assets are meant to keep working."

The refusals beyond game cloning are user-reported. Tom's Hardware reported that developers also describe Claude Code and Opus 5.5 blocking routine reverse-engineering, including work with the Reverse Engineer Anything tool. A developer at Conflict Simulations LLC said in a GitHub issue filed October 30 that Claude Code stopped midway through commissioned board-wargame modules, and that refusals began only after the developer asked whether the new rule applied. Anthropic has published no formal policy or changelog entry for the change, and the usage policy it published on October 8, which takes effect on November 12, does not mention games, per the retro-handheld site Held Games.

The backdrop is a game market that spent October fighting AI clones. Steam Next Fest filled with low-effort copies, IGN Nordic reported. The studio Digital Sun canceled a public playtest for its game ReVamp on October 19 over worries its demo could be cloned, Game Developer reported. A community tracker that catalogs AI-assisted game reverse engineering listed 273 projects on October 30 and credited Claude in 226 of them, Held Games reported.

The rule may still be narrower than the headlines. XDA found that when asked whether they could recreate Pokemon Diamond, Opus 5.5 and Opus 5 both initially refused, but Opus 5.5 agreed to help with a Pokemon Diamond decompilation project, explicitly distinguishing reverse engineering from recreating a game, and Opus 5 said it would assist with legitimate decompilation projects.

For developers building video and media tooling with Claude, part of the model's behavior is now set on Anthropic's servers rather than in the version on their drive. If the same prose-based guardrails meet a workflow that resembles a named product, refusals mid-project are a real risk; the wargame developer asked Anthropic to document a verification path for licensed work, and none has been announced.

Claude Code still builds original games and games in a genre, per Osmani. The rule is live in current clients now.