Add MIXED on Google
Choose MIXED as a preferred source in Google Search.
Anthropic has added instructions to Claude Code on its Opus 5.5 model intended to discourage users from recreating someone else’s specific game. The company says original games, games in an existing genre and games made from a user’s own designs and assets are meant to remain possible.
The update comes as independent developers raise concerns that AI tools could help others quickly copy their games or demos and release competing versions. Anthropic describes the change as an attempt to steer behavior, not proof that every request for a game clone will now be blocked.
“We added two sentences to Claude Code’s prompt on Opus 5.5 to steer it away from recreating someone else’s specific game,” Anthropic technical staff member Addy Osmani said, according to Game Developer, which received confirmation from an Anthropic spokesperson.
What the Claude Code instruction covers
Game Developer reports that an X user spotted a Claude Code instruction telling the tool to build original games or games based on a user’s own work, but not recreations of a specific existing game, even when renamed. The outlet reported that the instruction was pushed around October 27; Anthropic’s confirmation identifies the scope as Claude Code with Opus 5.5.
Osmani said Anthropic made the change because using Claude to infringe intellectual property violates its usage policy. He also said the company would continue refining the behavior and asked users to report cases where Claude refuses work that belongs to them.
That distinction matters for legitimate developers using the assistant to work on their own projects. A refusal in an individual session does not establish that the developer lacks rights, and Anthropic’s statement does not explain how Claude determines ownership. It is also not a blanket ban on making games in a familiar genre.
A response to a wider concern around game copies
The new instruction is separate from Valve’s decisions about what appears on Steam. Valve recently addressed developers’ concerns about AI-generated copies, saying it did not want to dictate which tools developers use. Anthropic controls Claude Code’s behavior; it does not control the Steam store or other coding models.
Some studios have already changed how they share games before release. Game Developer reported that Moonlighter developer Digital Sun delayed a public playtest for ReVamp over fears that it could be imitated.
The new prompt may make a particular Claude Code workflow less useful for copying, but Anthropic has not shown that it eliminates cloning or stated that every other model and interface uses the same instruction. Developers can still build from their own designs, while how the rule handles borderline requests remains to be seen.