Anthropic adds Claude Code rules to block game cloning

Anthropic has added instructions to its Claude Code coding tool aimed at preventing the reproduction of other developers' games, according to game.donga.com. Anthropic engineer Addy Osmani said on X that two sentences were added to the Claude Code instructions used with Claude Opus 5.5.

The instructions direct Claude to refuse requests to replicate a specific game, since using Claude to infringe others' intellectual property violates company policy. Osmani drew a distinction between requests to build a game in a given genre and requests to recreate a specific existing game.

Games that follow an established genre's conventions, or that use graphics and audio the user designed and created, may still be developed. Copies of a specific game with only the title changed, or presented as original works, are restricted.

Earlier refusals drew developer complaints

In October, Osmani said on X that he had added two sentences to the Claude Code instructions for Claude Opus 5.5. On October 30, a developer who said he runs the board game company Conflict Simulations posted on the official Claude Code GitHub, saying he had been porting customers' war board games into personal digital modules but that from around October 27 Claude began refusing the work. He said the work was blocked even though he confirms customers own the games and writes the code himself from scratch using the materials provided.

Osmani said the guidelines will keep being adjusted so that protecting other developers' work does not block creation, and invited users to report cases where Claude refused work on a game they had made themselves.