Anthropic needed just two sentences to stop Claude Code from rebuilding video games that belong to someone else.
In a post on X, Anthropic employee Addy Osmani confirmed that Claude Code’s system prompt for Opus 5.5 now contains two sentences preventing the tool from cloning existing games. According to Osmani, using Claude to infringe on intellectual property breaks the usage policy.
A new name doesn’t get a clone through
The rule has been active for several days. It applies even if a user gives the clone a different name or presents it as original work, so the easiest workaround is already closed off.
Game development itself isn’t the target. Building your own games, genre titles and projects that use custom assets is still allowed. Some users, though, say their original projects are getting blocked as well, which suggests the filter is catching more than it was designed to.
Halo and GTA Vice City, running in a browser
Anthropic made the change after a surge of cloning projects built with AI help. With Opus 5.5 and GPT-6 Astra, users have turned out hundreds of unofficial browser ports of popular games such as Halo and GTA Vice City.
Tools such as Reverse Engineer Anything lowered the barrier. It combines AI agents with reverse engineering to convert native binaries into readable pseudocode, giving a coding model concrete material to rebuild from.
The copying went beyond games. One developer drew headlines for recreating parts of Adobe’s Creative Cloud apps. Sony's PlayStation 5 was also affected after a jailbreak set off a fast wave of emulators.
Copyright disputes reach code
Generative AI’s intellectual property battles began with images and video, and they’ve now spread to software. For the moment, Anthropic is handling it with two lines in a system prompt, with no technical barrier behind them.
Osmani said Anthropic intends to keep adjusting the rules. If Claude Code turns down an original game you’re working on, you’ve hit the same false positives other users are already reporting.