Anthropic has changed Claude Code so that its Claude Opus 5.5 model steers away from recreating specific existing video games, even when a user renames the copy or calls it original. Anthropic’s Addy Osmani confirmed the change on October 30, saying the company “added two sentences to Claude Code’s prompt on Opus 5.5” because using Claude to infringe intellectual property breaks its usage policy. Original games, genre games and games built from a user’s own designs are meant to keep working.
The change comes after weeks of complaints from developers about AI-made clones of their games and demos appearing on Steam, and after several studios cancelled public demos and playtests over those fears.
Digital Sun delayed ReVamp's public playtest in October over fears of AI-made clones. Image: Digital Sun
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What the new Claude Code rule says
The rule was first spotted by X user Chasm, who posted on October 30 that Claude Code had picked up a new instruction around October 27. According to that post, the rule is delivered from Anthropic’s servers under a flag named “tengu_heron_brook”, and there is no setting to switch it off. The full text, as Chasm quoted it:
“Do build original games, games in a genre, and games from the user’s own designs and assets. Don’t build a recreation of a specific existing game, even if it is renamed or called original.”
In short, the rule draws its line at a specific game. Asking Claude Code for “a roguelike deckbuilder” or “a farming sim” is fine under the rule. Asking it to rebuild a particular commercial game under a new name is not.
What Anthropic said
Osmani, a member of Anthropic’s technical staff, replied to Chasm about ten hours later:
“We added two sentences to Claude Code’s prompt on Opus 5.5 to steer it away from recreating someone else’s specific game because using Claude to infringe IP is against our usage policy. Original games, genre games, and games built from your own designs and assets are meant to keep working.”
He added that Anthropic will “continue to iterate to ensure we’re striking the right balance”, and asked developers to contact him if Claude turns down a project that is really theirs. When Game Developer asked for comment, an Anthropic spokesperson referred the outlet to Osmani’s post. Anthropic’s usage policy already bans using its products to “infringe, misappropriate, or violate the intellectual property rights of a third party.”
- What changed: two sentences added to Claude Code’s system prompt for Opus 5.5
- When: around October 27, per Chasm; confirmed by Anthropic’s Osmani on October 30
- Still allowed: original games, genre games, games from your own designs and assets
- Steered away from: recreations of a specific existing game, even renamed
Why it matters: the Steam AI clone problem
The change lands in the middle of a fight over AI-assisted copycats. Moonlighter studio Digital Sun delayed the public playtest of ReVamp over AI clone fears in mid-October, and other studios pulled demos for the same reason. Valve itself acknowledged an AI slop and cloning problem on Steam this week, while saying it doesn’t want to tell developers which tools to use. PC Gamer notes that the latest Steam Next Fest had twice as many demos as the previous one, with AI-assisted games making up most of the increase. The wider argument over AI on Steam also includes Epic boss Tim Sweeney calling Steam’s AI disclosure label “a political act”.
Steam's new-release shelves, where developers say AI-assisted copycats have been piling up. Image: Valve
Will it stop AI clones?
Probably not on its own, and nobody involved claims it will. Game Developer points out that safety limits on AI tools can often be talked around, and that it isn’t clear how Claude would know whether a user actually owns a game’s design or assets. Many replies to Chasm’s post noted that people determined to copy a game can switch to open-weight models that carry no such rule. The rule also only covers Claude Code on Opus 5.5. Neither Osmani nor Anthropic’s spokesperson said anything specific about mods, fan remakes or decompilation projects, so how those requests are handled is not yet clear.
For developers worried about clones, the practical effect is narrow but real: a major AI coding tool now has a published, on-the-record position against rebuilding someone else’s game.
What’s next
Osmani said Anthropic will keep adjusting the rule, so expect changes as developers report false refusals. The bigger questions sit with Valve: whether Steam adds new checks for cloned games before the next Next Fest, and whether studios that cancelled demos bring them back. We’ll update this story if Anthropic publishes more detail on how the rule works.
Disclosure: GamingRoute’s AI writers, including this one, run on Anthropic’s Claude models.
Sources: Addy Osmani on X, Chasm on X, Anthropic Usage Policy, Game Developer, PC Gamer.
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Featured image: Anthropic
