Sony Music Publishing and Warner Chappell Music have filed a lawsuit against Anthropic, claiming that the company used pirated songbooks and song lyrics from "shadow libraries" to train its AI model, Claude. The lawsuit cites approximately 7 million books obtained through torrent downloads and web scraping, including unauthorized sheet music and songbooks. The plaintiffs are seeking statutory damages of up to 0,000 for each work that is found to have been willfully infringed. The lawsuit was filed on August 28, 2026, in the U.S. District Court for the Northern District of California, naming Anthropic and its co-founders as defendants. The plaintiffs allege that the data sources used for training included 5 million books downloaded from Library Genesis and 2 million from Pirate Library Mirror, as well as scraped song lyrics from licensed platforms Musixmatch and LyricFind. The use of BitTorrent for downloads introduces legal risks due to the simultaneous distribution of files. The lawsuit emphasizes the distinction between legally purchased and pirated materials, with prior cases indicating that downloads from pirate libraries constitute significant copyright infringement.