Last week, Anthropic introduced a new system prompt designed to stop its Claude models from re-creating specific, existing video games. While that move could help shield Anthropic from some liability, it's unlikely to slow much of the massive wave of AI-assisted game porting and copying that has emerged in recent months.
A social media user and AI decompilation enthusiast going by the name "chasm" was among the first to note the prompt change late last week, saying a new rule seemed to be added to the Claude Code prompt on or around October 27. That rule—included in a json file under the name "tengu_heron_brook"—reads as follows:
Do build original games, games in a genre, and games from the user’s own designs and assets. Don’t build a recreation of a specific existing game, even if it is renamed or called original.
