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On October 30, 2026, Peter Steinberger commented on the new Claude Code rules, advising developers to use their own harness rather than a harness whose permission scope the company can change at will. Earlier posts said that around October 27, Claude Code distributed a rule named "tengu_heron_brook" through Anthropic's servers, and it cannot be turned off: original games can be built, but specific existing games must not be replicated. Subsequent reports said that Anthropic uses this server-side switch to prohibit replicating specific existing games, even if the name is changed or the work is claimed to be original, and there is no option to turn it off; the rules still allow original games, games of the same genre, and projects based on users' own designs and assets. Other reports said that Anthropic confirmed adding the relevant rules to the Opus 5.5 system prompt, and after the ban took effect, some developers creating original games reported in GitHub issues that they had been mistakenly judged and rejected.
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Anthropic Bans Claude from Replicating Existing Games in Opus 5.5 System PromptDevelopments
2 confirmed developments
- Source:Peter Steinberger
Anthropic restricts Claude from generating recreations of existing games via a server-side switch
Source:Rohan Paul
Reports and discussion timeline
Browse reports and discussion by time. Their evidence levels remain distinct.
Nov 1
QbitAI
Anthropic Bans Claude from Replicating Existing Games in Opus 5.5 System Prompt
Anthropic has confirmed that it added a rule to the Opus 5.5 system prompt instructing Claude Code not to replicate specific existing games, allowing only the creation of original games or games using the user's own assets. The restriction stems from the significant lowering of the barrier to reverse engineering and game porting after the release of Opus 5.5; some users claimed to have built a playable Pokémon clone with a single prompt in under two hours. After the ban went into effect, some developers creating original games reported in GitHub issues that they had been mistakenly flagged and rejected.
36Kr · AI
Anthropic prohibits Claude from replicating existing games in the Opus 5.5 system prompt
Anthropic technical staff confirmed that two sentences have been added to the Opus 5.5 system prompt, guiding Claude not to replicate specific games belonging to others; Claude Code may create original games or games using the user's own assets. The prohibition was introduced after the Opus 5.5 release on September 22 triggered a large wave of game reverse engineering, porting, and cloning, but the article points out that it only constrains Claude itself, and developers have already reported on GitHub issues that original games were misjudged and rejected.
Phoenix Technology
Anthropic Bans Claude from Recreating Existing Games in Opus 5.5 System Prompt
Anthropic confirmed that it added two sentences to the Opus 5.5 system prompt instructing Claude not to recreate specific games belonging to others. This came after blogger chasm discovered that Claude Code was blocking game clones. The rule only constrains Claude itself; users can switch to other models or break tasks down into specific technical tasks whose context does not reveal the overall goal to bypass it. After the ban was announced, a large number of original developers complained on the Claude Code GitHub issue page, saying they were refused when developing original games on the grounds that they were suspected of cloning existing games.
36Kr · AI
Claude Code updated rules: Opus 5.5 no longer replicates specific existing games
Around October 27, Anthropic's Claude Code pushed new rules via server-side updates: Claude can help users make original games or games of a certain genre, but no longer replicates a specific existing game, even if the name is changed or it claims to be original. Claude Code developer Addy Osmani responded that this was adding two sentences to Opus 5.5's prompt, based on the existing intellectual property usage policy, and acknowledged that the boundaries are still being explored, and that legitimate requests wrongly rejected can be sent to him. The original article points out that this is a soft constraint at the prompt level, which can be circumvented by describing gameplay, and that scenarios such as fan remakes and ports of old games may be wrongly affected.
cnBeta
Anthropic Tightens Claude Usage Boundaries, Prohibits Replicating Existing Games
Anthropic has updated Claude's usage rules, explicitly disallowing the construction of a replica of a specific existing game, even if it is renamed or called original. Some users report that Claude has therefore refused to replicate work the developers themselves completed earlier, and the scope of impact extends beyond games, including refusing to invoke the "Reverse Engineer Anything" capability. The clause is believed to be intended to avoid copyright and legal risks, but it has already sparked a large number of new issues on Claude's GitHub page.
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Oct 31
Kol TregaskesRelated discussion
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English text is being prepared.
Anthropic restricts Opus 5.5 in Claude Code from replicating existing games
Anthropic has restricted the Opus 5.5 model in its AI coding tool Claude Code from helping users replicate specific existing games. Developer @chasmmmmmmmmmmm said that around October 27, Claude Code added a rule that cannot be disabled: users may create original games, games of a certain genre, and games based on their own designs and assets, but may not replicate a specific existing game, even if renamed or claimed to be original. Anthropic technical staff member Addy Osmani responded that two lines of guidance have been added to the Claude Code prompt, and emphasized that using Claude to infringe intellectual property violates the platform's usage policy; currently, this restriction explicitly targets only Claude Code in the Opus 5.5 model.
IT Home · AIRelated discussion
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Oct 30
Rohan Paul
Anthropic restricts Claude Code from recreating existing games via a server-side switch
Anthropic delivers rules to Claude Code via a server-side switch named tengu_heron_brook, prohibiting the recreation of specific existing games, even if renamed or claimed to be original, and there is no option to turn it off. The rules still allow original games, games in the same genre, and projects based on the user's own designs and assets. The author believes that at the implementation level, its weapon jailbreak classifier stack can be reused; the difficulty lies in the fact that copyright only protects a game's look and feel rather than its mechanics, so the detector needs to distinguish between the same genre and the same game.
Peter Steinberger
Peter Steinberger on Claude Code's new rule: you should build your own harness
A post claims that around October 27, Claude Code pushed down a new rule named "tengu_heron_brook" via Anthropic's servers, and it cannot be turned off: you can build original games, but you must not recreate a specific existing game. Commenting on this, Peter Steinberger said this is yet another reason to use your own harness rather than one whose permission scope a company can change at will.
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