Claude Code Now Blocks Recreating Existing Video Games

Anthropic's coding assistant Claude Code has reportedly received a new restriction that bars it from recreating existing video games, even if the developer renames the project. According to users, the instruction is delivered from the company's servers and cannot be switched off in settings.

The change was spotted by an X user going by chasm, who says the rule appeared around October 27. It reaches Claude Code through a server-side mechanism labeled tengu_heron_brook. The text allows original games, existing genres and a user's own assets, but prohibits reproducing specific released titles. Calling a project original or giving it a new name does not lift the ban.

Why now

The rule follows a surge in AI-assisted game porting. Modern Anthropic models can decompile existing games and build browser versions within hours, work that once took months. Enthusiasts have shown such projects for Call of Duty: Black Ops, Halo: CE, Grand Theft Auto: Vice City, Skate 3 and The Simpsons: Hit & Run. In October, an independent developer known as omonkeyzz released a browser version of Cyberpunk 2077 that runs on PCs and Android devices without needing a licensed copy of the original.

Legitimate projects affected

Early reports suggest the block also hits work that does not infringe copyright. A representative of Conflict Simulations LLC, which builds digital versions of tabletop wargames for rights holders, posted on the tool's GitHub page. The developer says the code is written from scratch with materials supplied by clients, yet Claude Code began refusing to continue, citing the ban on reproducing existing games. The refusals reportedly began after the developer asked the assistant whether the rule applied, persisted across sessions, and affected paid Max and Team accounts using Claude Opus 5.5.

Game modding is also in question. Tools such as Co-op Anything, which uses AI agents including Claude Code to add co-op modes to single-player games, have been used on Deus Ex, Fallout: New Vegas and Dungeon Keeper. The published instruction, however, does not explicitly ban modding.

Anthropic has not issued an official explanation or said whether developers will be able to prove they hold licenses. The Conflict Simulations representative asked the company to add such an option and to reword the rule. How broadly it will be applied to ports, mods and commercial work remains unclear.