Open on XAnthropic has added Claude Code instructions that steer the agent away from rebuilding named video games, including renamed clones. The change matters on this beat because Halo 64, LittleBigPlanet PC, and vibe-coded missions have leaned on Claude as a coding partner.
I haven't run Claude Code against the rule myself. This is based on Game Developer, XDA Developers, chasm's post, and Anthropic's reply on X.
What users spotted
On Oct 30, chasm posted that Claude Code picked up a new rule around Oct 27, pushed from Anthropic's servers under a flag called tengu_heron_brook, with no setting to turn it off. His screenshot shows the full text:
Full rule (from chasm's screenshot)
Wording as quoted by chasm on X, Oct 30, 2026.
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.Game Developer quotes the same rule with "Do not" instead of "Don't" in the second sentence. XDA Developers recovered matching wording inside Claude Code v2.1.314, using "Don't" like chasm's screenshot.
Anthropic's confirmation
On Oct 30, Addy Osmani (@addyosmani), a member of technical staff at Anthropic, replied to chasm:
Open on XGame Developer quotes him:
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.
Osmani added, in a separate sentence quoted by Game Developer: "In the meantime, if Claude turns down something that's yours, send it my way."
What it may still allow, and what is unclear
XDA Developers found a separate original_games_guidance / opus_5_5_prompt_bundle path, so Opus 5.5 may receive the restriction even when other models do not. In their tests, Opus 5.5 cited session instructions when refusing a Pokémon Diamond recreation, but still offered help on decompilation and static recompilation when asked directly. The instruction does not explicitly ban those techniques.
That leaves open questions for the port scene we track. Game Developer notes it is unclear how Claude can tell whether a user owns an idea or assets, and that open-weight local models have no such rule. XDA flags projects like Zelda: Wind Waker HD static recompilation and the Nxnative Switch compatibility layer, which translate or host existing binaries rather than rebuilding a game from scratch.
XDA also reports a developer who said Opus 5.5 refused paid work on digital board-wargame modules built from customer-owned materials. XDA did not independently reproduce those refusals.
