Anthropic Tells Claude Code to Stop Rebuilding Specific Games
Claude Code has picked up a new server-delivered instruction: build original games, but do not rebuild a specific existing game, even if it is renamed or called original. The change was first spotted around October 27 by X user Chasm and has since been covered by multiple tech and gaming outlets. It arrives under an internal flag named tengu_heron_brook, with no user-facing switch to disable it.
The disclosed wording draws a clear line. Claude is told to keep building original games, games in an established genre, and games based on the user's own designs and assets. Only one category is blocked: a recreation of a specific existing game. Anthropic frames the move as intellectual-property protection, saying that using Claude to infringe IP violates its usage policy.
Addy Osmani, a member of Anthropic's technical staff, confirmed the change on X. He said the company added two sentences to Claude Code's prompt on Opus 5.5 to steer it away from recreating someone else's specific game, adding that work on original games should keep working and that Anthropic is iterating on the wording. Game Developer sought comment from the company and was directed to Osmani's public explanation.
The rule explicitly closes the renaming loophole. XDA tested Opus 5.5 and Opus 5 by asking whether they could recreate Pokemon Diamond. Both initially refused, while Opus 5.5 specifically said its session instructions barred recreating specific existing games, including renamed versions. Opus 5 also initially suggested that decompiling or porting the ROM could be off-limits, but on follow-up it reconsidered and said it would assist with legitimate decompilation projects. Separately, XDA reportedly recovered matching instruction text from the Claude Code binary, supporting the claim that the restriction is active in at least some sessions.
Some developers say the guardrail is already blocking legitimate projects. Tom's Hardware reports additional complaints that Opus 5.5 is blocking generic reverse-engineering tasks, although it notes a direct link to the game-specific instruction has not been conclusively established. Wccftech similarly reports that while the restriction targets clones, developers say legitimate projects are being blocked.
Because the instruction is delivered from Anthropic's servers, it took effect without a client update and without an entry in the official changelog. Chasm and subsequent reports agree there is no setting to switch it off, so behavior is consistent across installations. One report identified the binary evidence in Claude Code v2.1.314.
Anthropic says it is iterating on the rule to stop infringing recreations without breaking original development. For developers, the open questions are practical: where the line sits between genre inspiration and recreation, whether legitimate reverse engineering will be unblocked, and whether any appeal path or scoping control will appear. No whitelist or toggle has been announced.