Music publishers see Anthropic’s earlier book-piracy settlement as inadequate deterrence and say Claude now poses a direct threat to songwriters; Anthropic counters that the complaint revives allegations already being tested in court and that generative-AI training is protected fair use.

The dispute traces back to Anthropic’s acquisition of training material. The new complaint alleges that co-founder Benjamin Mann began using BitTorrent in July 2021 to obtain millions of pirated books from Library Genesis, with later downloads from Pirate Library Mirror after pirate-library shutdowns. Publishers point to internal staff messages, including “zlibrary my beloved,” as evidence that piracy was treated as a shortcut to fresh data.¹

That alleged book trove is central to the music case because, publishers say, it included songbooks, sheet music and lyric collections. Sony Music Publishing, Warner Chappell and others filed their suit late Friday in federal court in Northern California, naming Anthropic as well as Mann and CEO Dario Amodei. They seek damages over “tens of thousands” of copyrighted works—potentially billions of dollars if maximum statutory awards are imposed.²

The publishers’ argument goes beyond the act of downloading. They contend Claude can reproduce lyrics, pair them with chord-progressions and generate music that mimics the commercially valuable core of well-known songs. That, they say, creates a more concrete market-substitution case than the earlier authors’ litigation, particularly as AI-generated music competes for attention and royalties.

The lawsuit arrives after Anthropic’s $1.5 billion settlement with book authors in Bartz, a case in which a judge distinguished between lawful training use and unlawful acquisition through piracy. The latest complaint leans heavily on that history but broadens the alleged conduct to unauthorized lyric-site scraping and digitized songbooks. It calls the operation a “brazen campaign of illegally torrenting, scraping, and downloading copyrighted works on a massive scale.”³

Anthropic rejects that framing. A spokesperson said this is “the third lawsuit from the same lawyers, recycling allegations from cases already before the courts,” and maintained that training generative models is “a transformative fair use.”¹ The coming fight will test whether music publishers can show the market harm that authors struggled to establish—and whether Claude’s outputs make that difference decisive.