Recently, Claude Opus 5.5 started receiving complaints from users over the AI’s sudden inability to work in tandem with Reverse Engineer Anything, the very same tool that allowed users to decompile and open-source video games. At the time, no rules or updates had officially been announced by Anthropic.
Today, however, we have confirmation that Anthropic is deliberately pushing back against its users’ love of vibe-coded IP theft slop, as a new rule (a flag in Claude Opus 5.5’s code titled “tengu_heron_brook”) instructs the AI to safeguard against prompts that produce “a recreation of a specific existing game, even if it is renamed or called original.”
The new rule was seemingly first spotted by a user on X, but first appeared in Claude Opus 5.5’s changelog on October 27. While the new rule isn’t too fond of recreations “of a specific existing game,” it does still allow users to “build original games, games in a genre, and games from the user’s own designs and assets.”
ANTHROPIC IS CRACKING DOWN ON VIDEO GAME REWRITES 🚨
Claude Code picked up a new rule around Oct 27, sent from Anthropic’s servers under a flag called “tengu_heron_brook”. There’s no setting to turn it off.
The full rule: “Do build original games, games in a genre, and games… pic.twitter.com/0Zc5mQWHJt
— chasm (@chasmmmmmmmmmmm) October 30, 2026
In simpler terms, this appears to be a step beyond just cracking down on decompilations; Claude will now actively stop its users from attempting to vibe-code an original game that is influenced by a pre-existing one.
For instance, asking it to make a racing game should be fine, but asking it to create a racing game “like Need For Speed” would trigger Claude’s guardrails. However, according to reports from users over on r/Anthropic, it would seem that Claude is now pushing back on any and all forms of IP reproduction, game-related or otherwise.
“Lol yesterday I wanted to learn some info/spoilers from the web novel I was reading,” wrote a user in a post on r/Anthropic. “Claude refused to read unlicenced translation for me. Saying that’s illegal and immoral. The theft machine itself refuses to read scanlations.”
While it is funny to hear a Claude user openly refer to it as “the theft machine,” there are now multiple posts over on r/Claude complaining about newly introduced “safety classifier[s]” that seem to be limiting access to everything from security research to published coding books. Just speculation on my behalf, but it sounds like Anthropic was catching some heat for its users’ actions and has decided to—if you’ll excuse the pun—reverse course.