THE CRUNCH
Anthropic has added a rule to Claude Code designed to stop users cloning other developers' games. The rule, listed under the identifier "tengu_heron_brook", tells the model to build original games, genre games and games from a user's own designs and assets, but not to recreate any particular existing game, even one given a new name or passed off as original. The change was spotted by X user Chasm and confirmed by Addy Osmani of Anthropic's technical staff, who said two sentences had been added to Claude Code's prompt on Opus 5.5 to discourage recreating another developer's specific game, since using Claude to infringe IP breaches the company's usage policy.
The move follows weeks of complaints from game developers that their games and demos had been copied with AI assistance. Several studios have cancelled planned public demos over fears that demo code would be reverse engineered into clones. The backdrop is Steam's influx of low-effort, AI-assisted imitations: the most recent Steam Next Fest saw twice as many showcased demos as the previous event, and AI-assisted games drove most of that growth. Valve has acknowledged the platform has an AI slop problem.
Opus 5.5 has proved adept at reverse engineering code, with effects ranging from quick decompilation of old console games to a PS5 jailbreak. Tom's Hardware reports that users have also encountered refusals on broader reverse-engineering tasks, including use of the Reverse Engineer Anything tool, and that Claude Code's GitHub has seen complaints about refusals of standard game work mid-development. Some developers have claimed Claude blocked their own games' anti-cheat and security work, though Anthropic has not officially addressed those reports.
Osmani said original games, genre games and games built from a user's own designs are meant to keep working, and invited users whose legitimate projects are refused to contact him. Anthropic intends to keep adjusting the approach to strike the right balance.