Authors Andrea Bartz, Charles Graeber and Kirk Wallace Johnson alleged in the lawsuit that "an essential component of Anthropic's business model — and its flagship 'Claude' family of large language models (or 'LLMs')— is the largescale theft of copyrighted works," later alleging that "Anthropic downloaded known pirated versions of Plaintiffs' works, made copies of them, and fed these pirated copies into its models."

The lawsuit follows Anthropic's June debut of its most powerful AI model yet, Claude 3.5 Sonnet. Claude is one of the chatbots that, like OpenAI's ChatGPT and Google's Gemini, has exploded in popularity in the past year.