Attorney AI use
Landberg v. City of New York
An appellate brief contained fictitious cases and fabricated quotations generated during AI-assisted research, followed by an initial denial and a later admission at argument.
$10,500 in sanctions01
Case background
Material facts
On appeal in a sidewalk-liability action, counsel relied on a brief that cited three fictitious decisions, attributed invented language to New York’s highest court, and misstated real holdings. As the court observed of one supposed authority, “No case by that title exists at all, much less at the citation given by the plaintiff’s brief.” (Slip op. at 2.) Counsel initially attributed the errors to other briefs or string citations. At oral argument, he acknowledged that the nonexistent authorities came from AI-assisted research he had failed to verify.
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The decision
The court’s ruling
The court imposed $8,000 on the lawyer and $2,500 on the firm. It reserved the question of additional professional discipline.
Why it matters
What the decision means
Counsel had an obligation to verify even authorities offered for supposedly basic propositions. The initial filing error became more serious when counsel failed to investigate and candidly disclose its source.
Primary reading