Employee Addy Osmani confirmed on X that two sentences in Claude Code's system prompt for Opus 5.5 now prevent the tool from cloning other people's games. Osmani said that using Claude to infringe intellectual property violates the usage policy. The rule has been active for several days.
The change follows a wave of AI-assisted projects that produced hundreds of unofficial browser ports of well-known titles such as Halo and GTA Vice City, using Opus 5.5 and GPT-6 Astra. Tools such as Reverse Engineer Anything pair AI agents with reverse engineering to turn native binaries into readable pseudocode. A developer also recreated parts of Adobe's Creative Cloud apps.
Users can still build their own games, genre titles and projects with custom assets, though some report problems with original projects too. Osmani said Anthropic plans to keep adjusting the rules.
Why it matters if you build agents
Agents built on Claude Code should expect refusals for tasks that reproduce existing games, and renaming a clone will not get around the rule. Developers building original game projects should test whether the restriction triggers on their work, since some users have already reported this. Teams that depend on Claude Code for game work should watch for further changes, because Anthropic says the rules will keep changing.
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