Claude Code Games Rule Blocks Recreations of Existing Titles

Claude Code games requests now come with a new limit. Anthropic has added an instruction to its AI coding tool that tells Claude not to build a recreation of a specific existing video game, even if the copy is renamed or described as original. The company confirmed the change on October 30, saying it applies to Claude Code when it runs on Opus 5.5.

The rule first surfaced on X, where a user posting as chasm said Claude Code picked up the instruction around October 27. It is delivered from Anthropic’s servers through a configuration field named “tengu_heron_brook,” and according to that post there is no setting to switch it off. The post passed 1.8 million views within a day.

What the Claude Code Games Rule Says

The instruction is two sentences long: “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.”

Addy Osmani, who works on Claude Code at Anthropic, explained the reasoning in a reply on X. An Anthropic spokesperson pointed Game Developer to the same statement.

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. Original games, genre games, and games built from your own designs and assets are meant to keep working. We’ll continue to iterate to ensure we’re striking the right balance.

— Addy Osmani (@addyosmani) October 30, 2026

In other words, asking for “a farming sim” or “a deck builder” is fine. Asking Claude to rebuild a named commercial game level by level under a new title is not. Anthropic’s usage policy already banned using its products to infringe intellectual property; the change makes Claude Code enforce that at the moment of the request.

Decompilation and Ports Still Appear to Work

XDA Developers said it found the exact instruction inside version 2.1.314 of the Claude Code binary, along with a separate mechanism that can apply it to Opus 5.5 on its own. In XDA’s tests, Opus 5.5 refused to recreate Pokemon Diamond and cited its session instructions.

The restriction looks narrower for reverse engineering. The same model agreed to help with a Pokemon Diamond decompilation project, offering to turn disassembled functions into readable C, rebuild the ROM from the user’s own copy and write tooling. It also agreed to help with a static recompilation that would run the game natively on Windows. That matters for fan port projects, which have used AI to move older console games to PC and Mac.

Why Anthropic Acted Now

The change lands as indie developers grow worried about fast AI clones. Some studios have canceled public playtests out of fear a demo could be fed into an AI tool and copied before launch, and Valve this week told developers it won’t ban AI games on Steam but sees community and updates as the best defense against clones.

The rule has limits. It gives no definition of what counts as a recreation, it is unclear how Claude can tell whether a user owns the assets they upload, and open-weight models carry no such restriction. Osmani said users can send him cases where Claude turns down a project that is genuinely theirs.

What It Means for Developers

For most people building games with Claude Code, nothing changes: original ideas, genre projects and your own assets are still supported. The tool has been changing quickly, from the new Claude Ultra plan to recent security issues such as the Claude Code extension backdoor, and Anthropic says it will keep adjusting the game rule to strike the right balance.