Published opinion, 3 September 2026 · source · PDF · 19 pages
While reviewing appellee’s brief, the court discovered that it contained multiple citations to cases that the court was unable to locate or confirm as legitimate. On June 22, we issued an order requiring appellee to show cause “why the court should not strike its brief for citing nonexistent cases that are possibly the product of artificial intelligence (AI) hallucinations.” The next day, one of appellee’s attorneys at the firm, Loishirl W. Hall, filed a response in her own capacity.1 Ms.
Hall, filed a response in her own capacity.1 Ms. Hall confirmed that four of the brief’s cited authorities did not exist.2 She acknowledged that these citations were “not legitimate legal authority” and “should not have appeared in a brief filed with this Court.” Ms. Hall explained that she had “used Google’s generative artificial intelligence search tool to assist in locating case authority ” and did not verify the existence or accuracy of those citations before filing the brief.
3 I. The Known Risks of Using AI in the Practice of Law The use of AI is now so pervasive in legal practice that attorneys can no longer credibly claim ignorance of its pitfalls, including its propensity to hallucinate legal authority. See Fletcher v.
2026) (“If it were ever an excuse to plead ignorance of the risks of using generative AI to draft a brief without verifying its output, it is certainly no longer so. ”). The first high- profile incident of AI- fabricated case citations in the federal system occurred in the Southern District of New York over three years ago. Larry Neumeister, Lawyers blame ChatGPT for tricking them into citing bogus case law , AP News (June 8, 2023), https://apnews.com/article/artificial-intelligence-chatgpt- courts-e15023d7e6fdf4f099aa122437dbb59b; https://perma.cc/ZN2N-TSM9 .
We turn now to the issue at hand: AI hallucinations. T he citation of nonexistent cases has become the “frequent posterchild” for AI mishaps. In re Nwaubani, 2026 WL 687194, at *3 (collecting cases).
Blanche, 177 F.4th 1014, 1025 (9th Cir. 2026) (“Attorneys do not need cutting-edge technology to fabricate citations and make demonstrably false and unsupported statements. And the ethical and procedural rules we apply today do not turn on the source of such error. ”).
Lawyers using generative AI must thus be aware of the tendency of generative AI to make these mistakes and guard against them.” (citation modified)). The harm inflicted by the submission of hallucinated authority cannot be overstated. We expect attorneys, as officers of the court, to submit briefing that “give[s] us the best view of what the law is, and how that law supports their clients”; indeed, we rely on that briefing to help us reach the correct conclusion.
Jan. 16, 2026) (“Obviously, it ‘is not acceptable for parties to submit filings to the Court containing citations to legal authority that does not exist, whether drafted with the assistance of artificial intelligence or not.’” (quoting Williams v. Cap.