Anthropic Bans Claude from Replicating Existing Games in Opus 5.5 System Prompt

In recent days, a tweet on X went viral.

A blogger named chasm discovered that Claude Code seems to be quietly cracking down on game clones, not allowing it to be used to replicate other games.

Soon, Anthropic officially confirmed it too. Technical staff said they added two sentences to the system prompt of the Opus 5.5 model, guiding Claude not to "recreate a specific game that belongs to someone else."

This is very much in line with Anthropic's consistent style of prioritizing safety. But is it really useful?

More than a month ago, the powerful Opus 5.5 was released, like opening Pandora's box of game cloning. Cracking, modifying, and porting games became easier than ever before.

Would you believe it? Now you don't even need to buy a console and a legitimate disc—you can play GTA 5 and Call of Duty directly in the browser, and some people have even played Xbox-exclusive Halo 2 and Nintendo's The Legend of Zelda: Breath of the Wild on a jailbroken PS5.

The results are absurdly good.

What's even more critical is that not only are highly anticipated blockbusters like GTA 6 being massively leaked before release, but many indie game developers' hard-made games may be fully "replicated" by AI overnight as soon as the demo is released, sometimes even launching earlier than the original.

Some say the gaming industry is experiencing its own "Napster moment."

This term refers to the emergence of a disruptive technology that completely overturns the old industry order. Just like how MP3 and BitTorrent downloads turned the traditional record industry upside down back then.

And AI, represented by Claude Code, wants to close this Pandora's box it opened itself, but that is probably beyond its control.

You have no idea how surreal the gaming world has been recently.

Mario runs into Elden Ring, hopping and bouncing as he stomps those hideous bosses to death.

Spider-Man is no longer staying in New York either—he heads over to Gotham City in the neighboring DC universe, swinging around in Batman's territory.

It reminds me of the vibe of watching Ultraman fight Godzilla when I was a kid...

And the "root of all evil" behind all this traces back to Opus 5.5, which Anthropic released on September 22.

This model's huge leap in coding capability delighted hackers and game modders. They found that reverse engineering and decompiling game code—tasks that used to be incredibly complex and tedious—can now be done by AI.

As a result, all kinds of "Guan Gong fighting Qin Qiong"-style game modifications have emerged.

But this is just an appetizer.

Going further, the concept of "platform exclusivity" is being dismantled.

As everyone knows, one of the core moats of console makers like Sony, Microsoft, and Nintendo is their respective exclusive games. If you want to play God of War, you have to buy a PlayStation; if you want to play Halo, you have to buy an Xbox.

But now, hackers have used AI assistance to "jailbreak" the PS5. And the result?

Not only was backward compatibility achieved, allowing play of old PS2 games.

Absurdly, they even made an Xbox emulator, enabling the PS5 to successfully run the Xbox-exclusive Halo 2, and even Nintendo's Zelda.

The console war seems to have lost its meaning overnight.

Thus came the scene at the beginning. Anthropic added a rule to Claude Code:

You may create original games, games of a specific genre, and games made using the user's own designs and assets. Do not replicate an existing specific game, even if you change the name or call it an original game.

Frankly speaking, this approach is typical "surface-level work."

It looks lively, but actually, for managing game cloning, it is basically useless.

Why do I say that?

First, it can only control Claude itself.

How many large models are on the market now? Besides Claude, there is ChatGPT, and countless open-source models.

People making game clones can completely use other models to generate the main framework. Even if they encounter technical problems they can't solve, they can break the task down into very specific tasks with no visible context, and then throw them to Claude Code.

For example, I can replace all names and tags related to "Pokémon," and just let Claude blindly complete a purely technical task of "implementing some kind of creature capture and battle mechanism."

Not long after the ban came out, Claude Code's GitHub issue page was flooded.

A bunch of legitimate developers complained that while they were developing completely original games, halfway through, Claude suddenly went on strike, citing "suspected replication of an existing game."

Others merely wanted to reproduce a common game mechanic or patch their own tabletop game, and were ruthlessly refused.

I have always felt that Anthropic's rush to draw a line this time is more about posture than practice.

That sounds a bit harsh, but... it also seems to be the truth.

I wonder if everyone still remembers how the music industry was changed at the beginning of this century.

Before Napster appeared, we had to buy cassettes or CDs to listen to music. An album had more than a dozen songs, and even if you only liked one of them, you had to pay for the whole record.

Later, MP3 and peer-to-peer download technology emerged. Overnight, almost all songs could be downloaded for free online. The entire CD industry, along with the massive distribution system behind it, collapsed instantly.

This is the so-called "Napster moment."

A disruptive technology forcibly changed the rules and business models of an entire industry.

Now, the exact same thing is repeating in the gaming industry.

An indie game studio called "Alliance Arts" recently canceled the public demo of their upcoming new game, Drunken Goddess Reflux.

Users have already conducted experiments, using the free Claude Opus 4.6 model with just one prompt:

Make a Pokémon clone as close to the original game as possible.

In less than two hours, a fully functional, completely playable Pokémon clone was made.

In the past, hackers cracking games was an extremely long "cat-and-mouse game."

Hackers found vulnerabilities and released cracks, then companies like Sony and Nintendo released system updates to patch the vulnerabilities, and the hackers started all over again.

This used to be a confrontation with high technical barriers and high time costs.

The gaming industry is facing an intellectual property "whack-a-mole" game of unprecedented scale.

Take playing AAA blockbusters in the browser, for example. Game companies can of course send lawyer's letters demanding that a certain website take down cloned games. But then what?

The cost of making these browser ports is so low and the speed so fast—what can stop another person from making another one on another website with equally simple code?

But on the other hand, this technology is very likely also destroying the entire gaming industry ecosystem with its own hands, leaving those who create the games we love with nowhere to go.