IXSOR Case Briefs.

What this is. #

The post-Mata case law on AI in legal practice has grown into a distinct doctrinal domain: a verification duty under FRCP 11 and state-rule analogues, a privilege framework that depends on the AI vendor's data-handling terms, and a body of sanctions practice that runs from the trial-court level to the state supreme courts. This page collects IXSOR's reading of each case in the chain.

Each brief follows the same structure: what happened, the holding, the court's reasoning, the operational implication for firms, and the primary sources. Each is read against the underlying primary-source materials wherever possible.

The current library. #

1. Mata v. Avianca, Inc.
   678 F. Supp. 3d 443 (S.D.N.Y. 2023)

   An attorney who files a brief containing AI-generated fabricated case citations violates FRCP 11(b) regardless of subjective good faith, because the rule's "reasonable inquiry" element requires the attorney to verify each cited authority exists and supports the proposition for wh

2. Park v. Kim
   91 F.4th 610 (2d Cir. 2024)

   An attorney's duty under FRCP 11 includes verification of cited authority, and filing a brief containing fabricated case citations is sanctionable conduct regardless of the technology that produced the fabrication. Referral to the Second Circuit's Grievance Panel is the standard

3. Heppner v. United States
   No. 24-cv-XXXX (S.D.N.Y. Feb. 17, 2026)

   Disclosure of confidential client information to a consumer-tier generative AI service (here, ChatGPT) may constitute a waiver of attorney-client privilege and work-product protection where the vendor's terms of service permit the vendor to retain, review, or train models on user

4. Witkins v. McGreevy
   Oregon Supreme Court (June 2026) (mandamus petition dismissed)

   A mandamus petition supported by fabricated case citations generated by an AI tool is properly dismissed in its entirety. The Oregon Supreme Court declined to grant leave to amend after the petitioners had been put on notice of the fabricated authorities and had submitted further

5. Aldridge v. Tussing
   Oregon Supreme Court (June 2026) ($500 fine; resubmission permitted)

   AI-fabricated citations in a respondent's filing warrant a monetary sanction under the court's inherent power. Unlike the parallel petitioner-side case of Witkins v. McGreevy, the court permitted resubmission of corrected filings rather than dismissing the matter outrigh

6. In re Lacey (Lewis Brisbois sanctions)
   C.D. Cal. (2024-2025) (firm-level sanctions order)

   A firm-level sanctions order is the proper response where the firm's lawyers collectively submitted briefs containing AI-generated false citations and falsified quotations. The order included monetary sanctions, disqualification, and referral to state bar counsel for each involve

7. Kohls v. Ellison
   741 F. Supp. 3d 901 (D. Minn. 2024)

   A litigant's expert declaration that itself contained AI-generated fabricated citations was struck from the record. The court emphasized that an AI-produced declaration carries the same verification duty as an AI-produced brief, and that the duty runs against the lawyer who files

What's coming. #

The case-brief library is updated as new published decisions issue. Forthcoming additions in mid-2026 include the developing Lewis Brisbois follow-on orders, additional state-supreme-court rulings tracking Oregon, and downstream federal cases from the Charlotin AI Hallucination Database as they cross the published-decision threshold.

For the broader survey of the post-Mata sanctions landscape, see Mata, three years on.

This is a case-brief library, not legal advice. Dan Hughes is not an attorney; IXSOR does not provide legal services.