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# Anthropic says it added a Claude Code prompt rule against recreating specific games
- URL: https://theainewsfiles.com/anthropic-claude-code-rule-recreating-existing-games/
- Published: 2026-11-03T08:03:13.000Z
- Updated: 2026-11-03T08:03:13.000Z
- Description: Anthropic's Addy Osmani says two sentences were added to Claude Code's prompt on Opus 5.5 to steer it away from recreating someone else's specific game. Here is what is confirmed, what rests on one user's word, and what is questioned.
- Author: J E Cowie
- Tags: News

Anthropic has confirmed that it changed how its coding tool treats requests to rebuild existing video games. The company's Addy Osmani, a member of technical staff, wrote on X on 30 October 2026 that Anthropic added two sentences to Claude Code's prompt on Opus 5.5\. The sentences are meant "to steer it away from recreating someone else's specific game because using Claude to infringe IP is against our usage policy." This article separates what Anthropic has said from what rests on a single user's report.

## What the rule says

The wording was first spotted by an X user called Chasm, who wrote that "Claude Code picked up a new rule around Oct 27", under a flag called "tengu\_heron\_brook". It reads: "Do build original games, games in a genre, and games from the user's own designs and assets. Do not build a recreation of a specific existing game, even if it is renamed or called original."

Game Developer, PC Gamer and Engadget quote the rule in full in these words, as does a user's GitHub issue, with "Don't" in place of "Do not"; GamesIndustry.biz quotes parts of it. Nothing in it names a particular game or studio.

## What Anthropic has said

An Anthropic spokesperson referred Game Developer to Osmani's post. Osmani wrote that "original games, genre games, and games built from your own designs and assets are meant to keep working." He added that Anthropic would "continue to iterate to ensure we're striking the right balance". He also invited users to get in touch: "In the meantime, if Claude turns down something that's yours, send it my way."

Chasm said the rule was sent from Anthropic's servers and that there is no setting to turn it off. Osmani said Anthropic added two sentences to Claude Code's prompt on Opus 5.5.

## The pressure behind it

Game Developer ties the change to a wave of AI-made game remakes over recent months. It reports that Digital Sun Games is one of several studios to cancel a public playtest of its upcoming game ReVamp for fear someone would feed the demo into an AI tool. GamesIndustry.biz says the studio delayed the playtest. Game Developer also reports that developers have pressed Valve on how it will stop clones supplanting their games on Steam.

PC Gamer reports that at Steam's Indie Connect event, Valve's Tom Giardino said Valve doesn't want "to be gatekeepers telling developers which tools they should or shouldn't use." Engadget reports a surge of big-budget games being decompiled with AI help and made playable in browsers, naming Halo: Combat Evolved, Call of Duty: Modern Warfare 2 and Grand Theft Auto V as vibe-coded fan projects.

## Does it work?

Game Developer is sceptical. It says the rule may deter only the most low-effort copycats. Its reasons are that scientists and reporters have repeatedly documented that safety limits on generative AI tools can be sidestepped with rhetorical tricks, and that it is unclear how the software could tell whether a user owns a game idea or assets. It adds that users replying to Chasm pointed out that cloners can turn to open-weight models without such restrictions. GamesIndustry.biz, citing Game Developer, repeats the first two points.

One user's account gives a sense of how it plays out. On 1 November, a GitHub user opened an issue saying Claude Opus 5.5 declined to implement a commercially published board game for private use with friends. The author says the session's system prompt contained the rule's wording and that Claude, asked why, quoted it as an instruction from Anthropic. The complaint is about how the refusal was worded, not whether Claude should have declined. The author says Claude first presented the refusal as its own line, and objects to wording that deterred the user and offered alternatives that did not fit what they wanted. The issue says the author had not tried to reproduce the behaviour. It is one user's report.

## Possible spill-over beyond games

Kotaku reports that users on r/Anthropic describe Claude refusing other intellectual-property tasks. One post said it refused to read an unlicensed translation of a web novel, calling it illegal and immoral. Posts on r/Claude, it adds, complain about newly introduced safety classifiers that seem to limit access to everything from security research to published coding books. Kotaku's writer adds, calling it speculation, that it sounds like Anthropic was catching heat for its users' actions. Kotaku also reports that users had recently complained Opus 5.5 could no longer work with Reverse Engineer Anything, a tool for decompiling and open-sourcing games, at a time when Anthropic had announced no rule. Of the coverage, only Kotaku carries these users' reports.

## Where it stands

Anthropic has said what the change is, what it is meant to protect and that it will keep adjusting it. Whether the rule catches the clones developers are worried about is, for now, an open question.

## Sources

Blake, V. (2026) 'Anthropic adds rule to stop Claude Code recreating existing games', GamesIndustry.biz, 2 November 2026, available at: [https://www.gamesindustry.biz/anthropic-adds-rule-to-stop-claude-code-recreating-existing-games](https://www.gamesindustry.biz/anthropic-adds-rule-to-stop-claude-code-recreating-existing-games?ref=theainewsfiles.com) (Accessed: 3 November 2026).

carrotRakko (2026) '\[MODEL\] Refusals driven by a product instruction are worded as Claude's own judgment and as deterrence, not as a product limitation', GitHub (anthropics/claude-code, issue #106591), 1 November 2026, available at: [https://github.com/anthropics/claude-code/issues/106591](https://github.com/anthropics/claude-code/issues/106591?ref=theainewsfiles.com) (Accessed: 3 November 2026).

Chen, J. (2026) 'Anthropic updates Claude to stop it from recreating existing video games', Engadget, 1 November 2026, available at: [https://www.engadget.com/2303469/anthropic-updates-claude-to-stop-it-from-recreating-existing-video-games/](https://www.engadget.com/2303469/anthropic-updates-claude-to-stop-it-from-recreating-existing-video-games/?ref=theainewsfiles.com) (Accessed: 3 November 2026).

Francis, B. (2026) 'Anthropic orders AI tool Claude to stop remaking video games', Game Developer, 30 October 2026, available at: [https://www.gamedeveloper.com/programming/anthropic-appears-to-have-ordered-ai-tool-claude-to-stop-remaking-video-games](https://www.gamedeveloper.com/programming/anthropic-appears-to-have-ordered-ai-tool-claude-to-stop-remaking-video-games?ref=theainewsfiles.com) (Accessed: 3 November 2026).

Lane, R. (2026) 'Anthropic updates Claude to 'steer it away' from letting users clone games following weeks of Steam being inundated with AI slop', PC Gamer, 31 October 2026, available at: [https://www.pcgamer.com/gaming-industry/anthropic-updates-claude-to-steer-it-away-from-letting-users-clone-games-following-weeks-of-steam-being-inundated-with-ai-slop/](https://www.pcgamer.com/gaming-industry/anthropic-updates-claude-to-steer-it-away-from-letting-users-clone-games-following-weeks-of-steam-being-inundated-with-ai-slop/?ref=theainewsfiles.com) (Accessed: 3 November 2026).

Osmani, A. (2026) 'We added two sentences to Claude Code's prompt on Opus 5.5 to steer it away from recreating someone else's specific game…', X, 30 October 2026, available at: [https://x.com/addyosmani/status/2116213240363729013](https://x.com/addyosmani/status/2116213240363729013?ref=theainewsfiles.com) (Accessed: 3 November 2026).

Parker, L. (2026) 'Anthropic Nerfs Claude Again To Stop Users From Making AI Slop Out Of Any 'Specific Existing Game'', Kotaku, 30 October 2026, available at: [https://kotaku.com/anthropic-nerfs-claude-again-to-stop-users-from-making-ai-slop-out-of-any-specific-existing-game-2000751665](https://kotaku.com/anthropic-nerfs-claude-again-to-stop-users-from-making-ai-slop-out-of-any-specific-existing-game-2000751665?ref=theainewsfiles.com) (Accessed: 3 November 2026).

## Picture credits

- Top picture: Dario Amodei, CEO of Anthropic. Photo: Simon Walker / No 10 Downing Street, [CC BY 2.0](https://creativecommons.org/licenses/by/2.0/?ref=theainewsfiles.com) ([source](https://commons.wikimedia.org/wiki/File:Dario%5FAmodei%5Fin%5F2023.jpg?ref=theainewsfiles.com))