Anthropic's Claude AI blocks video game cloning and reverse-engineering

According to multiple user claims, Anthropic's Claude Code and/or Opus 5.5 model are blocking attempts at innocuous reverse-engineering, including those using the Reverse Engineer Anything (REA) tool. A text rule reportedly instructs the model to avoid recreating a specific existing game, though there is no official confirmation of the rule's exact wording. Claude Code's GitHub has seen issues complaining about refusals to do standard game work, replicate a game mechanic, and patch a tabletop-like game.