Reddit has initiated legal action against AI startup Anthropic, accusing the company of unlawfully extracting large volumes of user-generated content from its platform to train the Claude chatbot.

The lawsuit, filed Wednesday in California Superior Court in San Francisco, claims Anthropic employed automated tools to access Reddit’s content without consent, violating the platform’s terms of service and compromising user privacy. Reddit alleges that Anthropic trained its AI models on user data without informing or obtaining permission from those users.

“AI companies should not be permitted to extract and use personal content without clear boundaries on how that data is handled,” said Reddit’s chief legal officer, Ben Lee. He noted that Reddit’s data partnerships—with companies such as Google and OpenAI—include provisions that protect user privacy, allow content deletion, and prevent misuse, unlike the practices Reddit accuses Anthropic of using.

Anthropic responded to the allegations by stating it “disagrees with Reddit’s claims and will defend ourselves vigorously.”

Founded in 2021 by former OpenAI leaders, Anthropic is best known for its Claude AI assistant. It partners commercially with Amazon, which integrates Claude into its Alexa voice assistant. Like many AI developers, Anthropic has used publicly available web data, including Reddit and Wikipedia, to train its language models.

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Reddit’s complaint diverges from typical copyright-based lawsuits brought against AI companies. Instead, it centers on Anthropic’s alleged violation of Reddit’s terms and its engagement in unfair business practices.

The legal filing cites a 2021 research paper co-authored by Anthropic CEO Dario Amodei, identifying specific Reddit forums—covering topics like gardening, history, and personal advice—as particularly valuable for training AI. The suit also refers to Anthropic’s argument to the U.S. Copyright Office that using large-scale web data for statistical AI training constitutes lawful use.

Now a publicly traded company, Reddit has used licensing agreements both to raise capital and to ensure protections for its users. The lawsuit highlights the platform’s growing efforts to safeguard its data as demand from AI firms for human-created content continues to increase.