Claude 5.1 adds song lyric ban after Sony, Warner suit

Anthropic's decision to publish system prompts is unusual, and the new index page makes comparing versions easier. The addition of strict copyright rules likely responds to the lawsuit from Sony Music Publishing and Warner Chappell. The example with Sonic shows how the model handles requests for copyrighted characters by offering an alternative.

The update also changes how Claude handles rude behavior. Instead of ending a conversation after a warning, Claude is now instructed to stay respectful but not submissive. This shift might mean fewer conversations are cut short, but the unpublished end_conversation tool still exists, suggesting the public prompt is not the full picture.

The new URLs for harm-reduction sites are a first for Claude's system prompts. These sites might see more visitors, but the move also signals a careful balancing act between safety guidance and legal exposure.