Claude's new system prompt really doesn't want to reproduce song lyrics

Anthropic has updated Claude's system prompts, now publicly available, to include strict guidelines against reproducing song lyrics, poems, or copyrighted material. This change, noted on September 2nd, 2026, and affecting models like Fable 5.1, comes shortly after news of lawsuits from Sony Music Publishing and Warner Chappell against Anthropic for training on song lyrics databases. Claude will decline such requests, offering analysis instead, though works published before 1929 are generally permitted.