Anthropic tells Claude to stop rebuilding specific existing games

What Anthropic changed

Anthropic has added a new rule to Claude Code, the version of its Claude assistant that helps write software. The rule tells the AI not to build a recreation of a specific existing game, even if the copy is renamed or labeled as original. As IGN reported, the aim is to curb the AI-made game clones that have been piling up on platforms such as Steam.

The rule showed up around Oct 27. It arrives from Anthropic's servers, so users did not install it themselves, and there is no setting to switch it off.

What the rule allows and blocks

The wording draws a clear contrast. Claude should build original games, games that follow a genre, and games made from a user's own designs and assets. It should not rebuild one particular game, and giving the copy a new name does not change that.

That leaves a lot of room. Making a platformer, a card game or a puzzle game in a familiar style is still on the table. Copying one named title is what the rule targets.

• Fine: an original game, or one in a general genre.
• Fine: a game built from your own designs and assets.
• Blocked: a rebuild of a specific existing game, even renamed.

Anthropic's explanation

The news was first spotted by an X/Twitter user named Chasm, according to Game Developer, which IGN cites. When Game Developer asked Anthropic for comment, the company pointed to a post by Addy Osmani, a member of its technical staff.

Osmani said the team added two sentences to Claude Code's prompt on Opus 5.5. A prompt is the standing set of instructions a model reads before it answers you. The reason he gave is that using Claude to infringe intellectual property, meaning to copy someone else's protected creative work, is against Anthropic's usage policy.

He also said original games, genre games and games from your own designs and assets are meant to keep working. Anthropic will keep adjusting the balance. His invitation to users was direct: "send it my way" if Claude refuses something that is genuinely yours.

That last point suggests the rule may sometimes catch the wrong thing. Anthropic seems to expect that and is asking for examples.

The Steam problem behind it

The change lands in the middle of a loud complaint from PC gamers. IGN says the term "AI slop" became especially common in gaming after Valve launched Steam Next Fest earlier this month. Players said their feeds filled with low-effort clones, including copies of games that had only just released their own demos.

Developers felt the damage. Some, including Alliance Arts, the developer of Drunken Goddess Reflux, and the developer of Who You, canceled their Steam demo plans and moved to private playtests instead. Valve said it was thinking about how to solve the problem.

It is not clear that any one event prompted Anthropic's rule. IGN says the reason is unknown, so the timing may be a coincidence. It is also unproven that this one rule will make a visible dent in the clone flood.

Gray areas and what comes next

The hardest question is where the line falls. A game that borrows a style or a mechanic from another is common and often welcome. A game that rebuilds a specific title is something else. The rule's wording covers the second case, but real projects will sit in between, so some gray area is likely.

The wider games industry has not settled how to treat AI. Epic Games' Tim Sweeney has argued Valve should drop its request that developers disclose games using generative AI materials. Super Smash Bros. creator Masahiro Sakurai has compared AI-generated games to low-quality goods. The developers behind VRChat have also drawn criticism over how they handle AI content.

Against that backdrop, Anthropic's rule is a narrow step. It does not stop other tools from making clones, and it does not address the Steam feed problem directly. It does make it harder to use Claude to profit from someone else's work.