Anthropic Blocks Claude Code From Cloning Existing Video Games

A guardrail that may misfire

Addy Osmani, a member of Anthropic's technical staff, explained on Twitter that two sentences were added to the Claude Code prompt on Opus 5.5 so it cannot recreate another person's specific game. Such cloning already goes against Anthropic's usage policies, but the company admits the filter could wrongly refuse legitimate requests. In that case, Osmani says, users can contact support.

The motive is intellectual property. As PC Gamer points out, Opus 5.5 is extremely good at reverse-engineering code, which has fed everything from a wave of recompiled console games, rebuilt to run natively on PC, to blatant clones that lift the content of original titles, including unreleased ones.

Indie studios pull their demos

The issue came to a head at the latest Steam Next demo festival, where AI-made content reportedly outnumbered human-made releases. Worse, some developers skipped demos altogether out of fear of being copied before launch.

Alliance Arts cancelled the demo of 'Drunken Goddess Reflux' and replaced it with a closed beta handed out by lottery. Digital Sun Games dropped the 'ReVamp' test, calling a public demo too risky. Studio Bitdot's 'Needle in a Haystack Simulator' attracted so many clones that the original now carries an "original" tag on its Steam page. Some studios are even considering delaying trailers so as not to reveal their signature mechanic or art style.

Valve has acknowledged the problem, with two business team leads noting that clones existed before AI and that the company does not want to be a gatekeeper. Its advice is that games should not rely on a single easily copied mechanic.

The fix covers only Claude Code on Opus 5.5. Other major AI companies have their own coding tools, and as these improve, more clones and low-quality content are likely to reach digital stores. It also remains to be seen whether a prompt change can hold up against users who simply rephrase their request.