Anthropic has added two sentences to Claude Code’s prompt on Opus 5.5 to prevent the tool from recreating a specific third-party game, as using Claude to infringe on intellectual property is against its usage policy. According to a message posted on X on October 30, 2026 by Addy Osmani, original games, genre games, and those built from their own designs and resources should continue to work.
- Anthropic has added two sentences to Claude Code’s prompt to stop it from recreating a specific third-party game.
- Original games and games built from one’s own designs remain allowed.
- AI tools are fueling a flood of copied demos, decompilations, and ports of retro games.
- The measure will likely not stop copying, because other models and open-weight alternatives remain available.
In this message, the developer reiterates the company’s position: ‘We will continue to adjust things to find the right balance. In the meantime, if Claude refuses something that belongs to you, send it to me.’ This measure comes as AI-assisted programming tools are fueling a stream of game projects based, one way or another, on existing work.
A Massive Wave
This stream includes improvised copies of game demos, which are leading some developers to fear publicly showing their early work. It also includes thousands of AI-assisted decompilation and porting projects for retro games. Where these operations previously required long and meticulous human work, current tools make them, according to the source, orders of magnitude more efficient, even though some seasoned programmers believe these ‘vibe-coded’ ports and decompilations do not reach the quality level of human-led projects.
The trend has grown so large that decomp.dev, a community several years old dedicated to the ‘brutally difficult and time-consuming task’ of game decompilation, has announced its closure. Its maintainer, Luke Street, writes that the rapid rise of AI tools has made it clear that ‘the community aspect of decompilation is broken,’ with newcomers ‘rushing to port games, particularly using decompilations they didn’t contribute to.’
The site had been designed, he recalls, to gamify decompilation: seeing the progress bar climb motivated people to advance when every fraction of a percent required real human effort. ‘Today, that same idea has turned decompilation into an empty numbers game, worsened by people who just want to burn tokens to make the numbers go up or “port the game to PC,” regardless of anything else,’ he laments.
A Difficult Task to Stem
Anthropic’s new guideline can be seen as an effort to curb these AI-assisted copies, but it seems unlikely to have a significant effect on a large scale. Copycats can indeed turn to other leading models that do not impose such restrictions. And if the entire AI sector were to ban this type of use, developers could fall back on cheaper, open-weight models, which are not subject to these limitations and are, according to the source, ‘not that far behind’ in terms of capabilities.
