Music publishers including Sony, EMI, and Warner Chappell have filed a lawsuit against Anthropic, alleging the AI company illegally torrented copyrighted musical compositions to train its Claude AI models. The complaint claims Anthropic's "mass campaign of illegal torrenting" began in July 2021, when co-founder Benjamin Mann used Bit Torrent to download millions of pirated books from Library Genesis (Lib Gen). Co-founder and CEO Dario Amodei is also named as a defendant.

The publishers argue that Anthropic's $1.5 billion settlement with book authors earlier this year is insufficient given its $2 trillion valuation, and that the company continues to violate copyright by training on pirated sheet music and song lyrics. Internal staff chats revealed that employees referred to the "Pirate Library Mirror" (Pi Li Mi) as "zlibrary my beloved," suggesting enthusiasm for the pirated content. The lawsuit seeks an injunction to stop Anthropic from using copyrighted works in AI training, warning that without it, the company will continue to harm songwriters competing with AI-generated music on the charts.