Concord Music Group v. Anthropic (Chen declaration)

What happened

Music publishers sued Anthropic for copyright infringement. In a discovery dispute over how large a sample of Claude prompts and outputs Anthropic should produce, Anthropic filed a declaration from Olivia Chen, whom the court's order describes as Anthropic's expert, on statistical sampling and margin of error.

At the hearing the publishers told the court that a citation in the declaration pointed to an article with a title and authors that did not match any real publication. Anthropic's counsel explained that Claude.ai had been used to "properly format" at least 3 citations and in doing so had generated a fictitious article name with inaccurate authors. The underlying article was real. The order records that it "exists, was properly linked to and was located by a human being using Google search." A manual citation check, counsel acknowledged, "did not catch th[e] error."

What the court did

In an Order on Joint Discovery Submissions entered May 23, 2025 (Dkt. 377), Magistrate Judge Susan van Keulen described the defect as "a plain and simple AI hallucination." She struck paragraph 9 of the declaration, the paragraph containing the defective citation, and wrote that "this issue undermines the overall credibility of Ms. Chen's written declaration, a factor in the Court's conclusion."

The order also noted the presiding district judge's civil standing order, which requires a certification that lead trial counsel "has personally verified the content's accuracy" where AI is used. No sanctions were imposed. On the underlying dispute the court ordered a sample of 5 million prompt-output pairs, which the order associates with an 11.3% margin of error.

Where it stands

The order resolved a discovery dispute in a copyright action that continued after it. The record reviewed for this entry shows no further proceedings about the declaration and no sanction proceedings.

The obligation it engaged

The matter engaged Clause 3, independent authority, in a narrow form. The source was real and a person had found it. The error entered at the formatting stage, when a system rewrote the reference and the rewritten version was not compared against the source. Clause 3 applies to every element of a citation, including title and authors, because each is a representation about the source.

It also engaged Clause 4, checkability before adoption. The formatted citation was easy to check and a check was performed, yet the error survived it. That is a reminder that checking has to be done against the source itself and not against a memory of what the source is. Because the system was used by counsel rather than the declarant, the matter also shows that an expert's declaration can carry AI-introduced errors the expert never saw. An expert who signs is adopting the whole text.

The court's remedy was limited in scope. It removed the paragraph that carried the citation and left the rest of the declaration in the record, while stating that the error weighed against the declaration's credibility as a whole.

Sources

• U.S. District Court for the Northern District of California (copy) · May 23, 2025
  Order on Joint Discovery Submissions, Dkt. 377
• Reason (The Volokh Conspiracy) · May 26, 2025
  Judge Strikes Part of Anthropic (Claude.AI) Expert's Declaration, Because of Uncaught AI Hallucination in Part of Citation
• Reason (The Volokh Conspiracy) · May 15, 2025
  Seemingly Nonexistent Citation in Anthropic Expert's Declaration

What could not be confirmed

Press reports describe Ms. Chen as an Anthropic data scientist; the order reviewed calls her Anthropic's expert. Whether the other formatted citations also contained errors was not confirmed.