Anthropic adds Claude Code guardrail on game cloning, Addy Osmani says

The update is a policy enforcement change rather than a product launch: two sentences added to the system prompt for Opus 5.5 now constrain what Claude Code will generate when a request resembles an existing game. According to Addy Osmani, the same conduct already violated Anthropic's usage policy, so the new text makes that boundary explicit inside the tool itself, and it is written to catch renamed or disguised clones rather than only exact copies.

The timing follows a wave of cloning activity. Users have been using Opus 5.5 and GPT-6 Astra to produce hundreds of unofficial browser ports of well-known titles like Halo and GTA Vice City, while tools such as Reverse Engineer Anything pair AI agents with reverse engineering to turn native binaries into readable pseudocode. A developer also drew headlines by recreating parts of Adobe's Creative Cloud apps, and a PlayStation 5 jailbreak led to a quick wave of emulators.

Anthropic's restriction stops short of banning game creation outright, and Osmani said the company plans to keep tweaking the rules going forward. That suggests the guardrail may be adjusted as Anthropic sees how it performs in practice, including the reported cases where original projects ran into problems.