AI Hallucination Cases

This database tracks legal decisions1 I.e., all documents where the use of AI, whether established or merely alleged, is addressed in more than a passing reference by the court or tribunal.

Notably, this does not cover mere allegations of hallucinations, but only cases where the court or tribunal has explicitly found (or implied) that a party relied on hallucinated content or material.

As an exception, the database also covers some judicial decisions where AI use was alleged but not confirmed. This is a judgment call on my part.
in cases where generative AI produced hallucinated content – typically fake citations, but also other types of AI-generated arguments. It does not track the (necessarily wider) universe of all fake citations or use of AI in court filings.

While seeking to be exhaustive (912 cases identified so far), it is a work in progress and will expand as new examples emerge. This database has been featured in news media, and indeed in several decisions dealing with hallucinated material.2 Examples of media coverage include:
- M. Hiltzik, AI 'hallucinations' are a growing problem for the legal profession (LA Times, 22 May 2025)
- E. Volokh, "AI Hallucination Cases," from Courts All Over the World (Volokh Conspiracy, 18 May 2025)
- J-.M. Manach, "Il génère des plaidoiries par IA, et en recense 160 ayant « halluciné » depuis 2023" (Next, 1 July 2025) - J. Koebler & J. Roscoe, "18 Lawyers Caught Using AI Explain Why They Did It (404 Media, 30 September 2025)

If you know of a case that should be included, feel free to contact me.3 (Readers may also be interested in this project regarding AI use in academic papers.)

Based on this database, I have developped an automated reference checker that also detects hallucinations: PelAIkan. Check the Reports Report icon in the database for examples, and reach out to me for a demo !

For weekly takes on cases like these, and what they mean for legal practice, subscribe to Artificial Authority.

State
Party
Nature – Category
Nature – Subcategory

Case Court / Jurisdiction Date ▼ Party Using AI AI Tool Nature of Hallucination Outcome / Sanction Monetary Penalty Details Report(s)
John Doe v. James P. Ehrhard, Esq. S.D. New York (USA) 1 December 2025 Pro Se Litigant Implied
Fabricated Case Law (1)
Warning
Unknown criminal case Ceuta (Spain) 1 December 2025 Judge, Prosecutor Implied
Fabricated Case Law (1)

See here for details.

⚠ Alleged AI Use
Hanson v. Nest Home Lending, LLC et al. D. Colorado (USA) 28 November 2025 Pro Se Litigant Unidentified
Fabricated Case Law (5)
False Quotes Case Law (2)
Misrepresented Case Law (4), Legal Norm (1)
Struck Filing; Order for future filings to include certificate; Required contact with the Federal Pro Se Clinic

Order to Show Cause is here.

Mertz & Mertz (No 3) Family Court (Australia) 28 November 2025 Lawyer Unidentified
Fabricated Case Law (1)
Costs Order; Bar Referrals 10000 AUD
Obermann v. Spring Financial Inc. BC CRT (Canada) 28 November 2025 Pro Se Litigant Implied
Fabricated Case Law (1)
Misrepresented Legal Norm (1)
Elías Axel Roberto Rafael s/ Abuso sexual con acceso carnal CSJ de Tucumán (Argentina) 28 November 2025 Lawyer Implied
Fabricated Case Law (3)
Misrepresented Case Law (3)
Attorney disqualified; Bar referral

"No puede soslayarse, como hecho de gravedad institucional, que la defensa técnica del imputado - en el momento procesal que constituye la última instancia de revisión extraordinaria local- haya presentado un escrito elaborado posiblemente mediante el uso de herramientas de inteligencia artificial, u obtenidos a través de medios no confiables y fidedignos sin ejercer el más mínimo control sobre la veracidad de las citas jurisprudenciales, la autenticidad de las fuentes invocadas ni la coherencia dogmática de los fundamentos empleados.

La conducta descripta trasciende el mero error material o descuido profesional: configura un supuesto de negligencia grave incompatible con los deberes de probidad, lealtad y diligencia que rigen la funcióndel abogado defensor.

La defensa penal no puede convertirse en unespacio de experimentación de medios y/o tecnologías de manera irresponsable que - aunque de utilidad potencial - requieren un manejo prudente, crítico y siempre supervisado por el criterio humano. El ejercicio de la defensa en juicio, protegido por el art. 18 de la Constitución Nacional y por los instrumentos internacionales con jerarquía constitucional, exige una intervención personal, reflexiva y fundada de quien ejerce la representación técnica. El uso automático y acrítico de un asistente artificial, o la utilización de fuentes con procedencia desconocida para producir un escrito en la instancia recursiva vulnera no solo el deber de diligencia, sino también el derecho del imputado a una defensa real y efectiva."

Boyd v. Protestant Memorial Medical Center S.D. Illinois (USA) 26 November 2025 Pro Se Litigant Implied
Fabricated Case Law (1)
Misrepresented Case Law (1)
Warning
The Doc App, Inc. d/b/a My Florida Green v. Leafwell, Inc. M.D. Florida (USA) 26 November 2025 Lawyer Unidentified
Fabricated Case Law (1)
False Quotes Case Law (1)
Misrepresented Case Law (1)
Costs Order; CLE Order; Order to file Order in any future filing; Bar Referral 1 USD
Source: Robert Freund
Tameer Peak v. Onika Tanya Maraj-Petty, et al. S.D. New York (USA) 26 November 2025 Pro Se Litigant Implied
Fabricated Case Law (1)
False Quotes Case Law (2)
Misrepresented Case Law (1)
Plaintiff cautioned to disclose and verify any AI use
Source: Jesse Schaefer
Lessard c. Longuépée Québec (Canada) 26 November 2025 Pro Se Litigant ChatGPT
Fabricated Case Law (4)
Warning
Carlos Maturin v. T-Mobile USA, Inc. D. New Mexico (USA) 25 November 2025 Pro Se Litigant Implied
Fabricated Case Law (3)
Costs Order 1 USD
Brian Smith v. Wells Fargo Bank, N.A. N.D. Mississippi (USA) 25 November 2025 Pro Se Litigant Implied
Fabricated Case Law (1)
Warning
Sebastian Rako v. VMware LLC (1) N.D. California (USA) 25 November 2025 Pro Se Litigant Implied
Fabricated Case Law (1)
Order to include a footnote reading 'Located through AI; Checked' for each future citation
Jane Doe v. Taro Pharmaceuticals U.S.A., Inc. N.D. California (USA) 25 November 2025 Pro Se Litigant Implied
Fabricated Case Law (2)
Show Cause Order
Jesse Andre v. Warden, FCI Danbury D. Connecticut (USA) 25 November 2025 Pro Se Litigant Unidentified
Fabricated Case Law (1)
False Quotes Case Law (2)
Misrepresented Case Law (3), Legal Norm (1)
Admonishment; Motion stricken with prejudice
South Central Ohio Job and Family Services v. Corey Mason CA Ohio (USA) 25 November 2025 Pro Se Litigant Implied
Fabricated Case Law (1)
Misrepresented Case Law (1)
Source: Jesse Schaefer
In re T.F., P.F., and S.S. Minor Children CA Ohio (USA) 25 November 2025 Pro Se Litigant Implied
Fabricated Case Law (5)
False Quotes Case Law (2)
Misrepresented Case Law (3)
Source: Jesse Schaefer
Re Walker SC Victoria (Australia) 24 November 2025 Lawyer CourtAid; ChatGPT
Fabricated Case Law (1)
Misrepresented Case Law (1)
Reprimand
Supplying Demand, LLC (Matter of) U.S. Government Accountability Office (GAO) (USA) 24 November 2025 Pro Se Litigant Implied
Fabricated Case Law (1)
Warning
M.H. v. C.S. CA Indiana (USA) 24 November 2025 Pro Se Litigant Implied
Fabricated Case Law (1)
Zero Point MGMT v. Chase Bank/JP Morgan Chase Co. S.D. New York (USA) 24 November 2025 Pro Se Litigant Implied
Fabricated Case Law (2)
Misrepresented Case Law (1)
Non-lawyer trustee barred from proceeding pro se
David Morris Clayman v. Scott Bessant S.D. Florida (USA) 24 November 2025 Pro Se Litigant Unidentified
Fabricated Case Law (1)
Warning
In re: Marguerite Latete Kilpatrick S.D. Ohio (Bankruptcy) (USA) 24 November 2025 Pro Se Litigant Implied
Fabricated Case Law (1)
Misrepresented Case Law (1)
Bryan Pletcher v. Village of Libertyville Police Pension Board CA Illinois (USA) 24 November 2025 Pro Se Litigant Unidentified
Fabricated Case Law (10)
False Quotes Case Law (11)
Misrepresented Case Law (1), Exhibits or Submissions (1)
Plaintiff's appellate brief stricken and appeal dismissed; sanctions motion granted
Oxford Hotel Investments Ltd v Great Yarmouth Borough Council Upper Tribunal (Lands Chamber) (UK) 24 November 2025 Pro Se Litigant Unidentified
False Quotes Case Law (1)
Yakov Magdalasov v. ByteDance Inc., TikTok Inc., and Maria Malvar S.D. New York (USA) 24 November 2025 Pro Se Litigant Implied
Fabricated Case Law (1)
Misrepresented Case Law (1), Exhibits or Submissions (1)
Pletcher v. Village of Libertyville Police Pension Board AC Illinois (USA) 24 November 2025 Pro Se Litigant Unidentified
Fabricated Case Law (5), Exhibits or Submissions (1)
False Quotes Case Law (6)
Plaintiff's appellate brief stricken and appeal dismissed
Linda Oliver v. Christian Dribusch United States District Court, Northern District of New York (USA) 21 November 2025 Pro Se Litigant Implied
Fabricated Case Law (1)
Warning
Alexey Dubinin v. Varsenik Papazian S.D. Florida (USA) 21 November 2025 Lawyer Unidentified
Fabricated Case Law (2)
False Quotes Case Law (1)
Costs Order; Bar Referral 4030 USD
Walker v. Collingwood General and Marine Hospital Human Rights Tribunal of Ontario (Canada) 21 November 2025 Pro Se Litigant Implied
Fabricated Case Law (1)
Misrepresented Case Law (2)
Request for Reconsideration denied
Morris Gafni v. Rapid Foreclosure Refunds et al. SC New York (USA) 21 November 2025 Pro Se Litigant Implied
Fabricated Case Law (1)
Warning
Michael Izquierdo v. Wipro Limited N.D. Ohio (USA) 21 November 2025 Pro Se Litigant Implied
Fabricated Case Law (1)
Warning
Syndicat des travailleuses et travailleurs c. Centre L’Autre Maison inc. Tribunal d'arbitrage (Québec) (Canada) 21 November 2025 Lawyer Implied
Fabricated Case Law (4)
Warning

"[134] Même si l’arbitre de griefs est un tribunal administratif moins formel que le sont laCour supérieure ou les autres tribunaux judiciaires, notamment parce que ses règles depreuve sont plus souples, il n’en demeure pas moins que c’est un tribunal. À l’évidence,le procureur qui, devant ce tribunal, s’appuie sur de la jurisprudence doit s’assurer qu’elleexiste.

[135] L’arbitre de griefs s’attend à ce que tous les procureurs qui plaident devant luisoient compétents, honnêtes, professionnels et respectueux de son autorité.Manifestement, celui qui soumet au tribunal des références jurisprudentielles inexistantesne satisfait pas ces attentes, car il induit, intentionnellement ou non, le tribunal et la partieadverse en erreur.

[136] Qui plus est, le procureur qui fait référence à de la jurisprudence qui n’existe pasrallonge inutilement l’arbitrage. On reproche déjà, souvent avec raison, la longueur etles coûts élevés associés à l’arbitrage de griefs. Ces problèmes seront exacerbés si lesinformations inexactes générées par les hallucinations d’outils d’intelligence artificielles’introduisent devant les tribunaux d’arbitrage en raison de la négligence des procureurs.Le présent cas en est un bon exemple.

[137] Enfin, le procureur qui fait référence à de la jurisprudence inexistante expose lapartie qu’il représente à devoir compenser les dommages que cela pourrait causer àl’autre partie.

[138] En définitive, référer à des décisions qui n’existent pas, comme l’a fait laprocureure patronale dans le présent dossier, est un geste répréhensible qui ne devraitjamais se produire en arbitrage de griefs. Ce comportement est d’autant plus grave quecette procureure est membre de l’Ordre des conseillers en ressources humaines agréés."

Ege Kilinc v. PMMUE Eduservices Private Limited, et al. S.D. New York (USA) 21 November 2025 Lawyer Implied
False Quotes Case Law (3)
Order to file a sworn statement -03 listing accurate and improper citations
Source: Jesse Schaefer
Gutierrez v. Lorenzo Food Group, Inc. D. New Jersey (USA) 21 November 2025 Lawyer Implied
Fabricated Case Law (1)
Misrepresented Case Law (1)
Court ordered hearing and production of drafts, metadata, and timesheets; no sanctions imposed yet.

Plaintiff's counsel filed an opposition brief containing several quotations and citations the Court could not verify, including at least one the Court described as a "fabricated quotation." Defendants first identified the potentially inaccurate citations in their reply. The Court ordered disclosure about AI use, production of drafts, metadata and timesheets, and set a hearing to determine responsibility and whether sanctions or bar referral are warranted.

Source: Jesse Schaefer
Mark Jennings v NatWest Group PLC Sheriff Appeal Court (UK) 21 November 2025 Pro Se Litigant ChatGPT
Fabricated Case Law (1)
Nuvola, LLC v. Wright Minnesota DC (USA) 21 November 2025 Lawyer Unidentified
Fabricated Case Law (1)
Monetary sanction; five educational presentations/CLE requirement; Bar referral 1000 USD
Source: Robert Freund
Shields v. First Financial Tennessee (USA) 21 November 2025 Lawyer Implied
Fabricated Case Law (5), Legal Norm (1)
Warning
In re Jackson Hospital & Clinic, Inc., et al. M.D. Alabama (Bankruptcy) (USA) 20 November 2025 Lawyer Unidentified
Fabricated Case Law (1)
False Quotes Case Law (1)
Misrepresented Legal Norm (1)
Public Reprimand; Revocation of pro hac vice privileges; Order to Serve Order on Clients; Diffusion of Order to Counsel's Bars

Show Cause Order here. Law firm explained what happened here.

In the ultimate order, the court noted that "In terms of competence, the threat to attorneys using generative artificial intelligence platforms powered by large language models is two-fold. First, danger exists that the attorney does not understand how the technology functions, believing that the output is real instead of “realistic-looking."."

In finding that the law firm acted with integrity, the Court noted with approval that it had repaid the other side's fees, to the tune of 55,721.2 USD.

Buchanan v. Vuori, Inc. N.D. California (USA) 20 November 2025 Lawyer ChatGPT-4, OpenAI, Claude, Clear Brief, Lexis Nexis & Westlaw
Fabricated Case Law (1)
False Quotes Case Law (1)
Monetary Sanction; Referral to the Bar; Motions stricken without leave to refile

Order to Show Cause is here.

Evans, et al. v. Robertson et al. (3) E.D. Michigan (USA) 20 November 2025 Pro Se Litigant Implied
Fabricated Case Law (9)
False Quotes Case Law (5)
Misrepresented Case Law (1)
Multiple filings stricken from the record; Revocation of online upload privileges

Show Cause Order is here.

Source: Volokh
Ekeocha v. U.S. Department of State U.S. District Court for the District of Columbia (D.D.C.) (USA) 19 November 2025 Lawyer Implied
Fabricated Case Law (1)
False Quotes Case Law (1)
Admonishment
Y.S. v. John Doe et al. D. Colorado (USA) 19 November 2025 Pro Se Litigant Implied
Fabricated Case Law (2)
Misrepresented Case Law (3)
Warning
Yuehong v. The Minister of Citizenship & Immigration Federal Court (Canada) 19 November 2025 Lawyer ChatGPT
Fabricated Case Law (1)
Monetary Sanction; Refusal to Anonymize Counsel's Identity 500 CAD
DJ v SN CA Alberta (Canada) 19 November 2025 Pro Se Litigant Unidentified
Fabricated Case Law (1)
Additional Costs 500 CAD
ECLI:NL:RBNNE:2025:4814 Rechtbank Noord-Nederland (Netherlands) 19 November 2025 Lawyer ChatGPT
Fabricated Case Law (1), other (1)
Misrepresented Case Law (1)
.
Moorehead v. Goodwill Industries of Northeast Texas E.D. Texas (USA) 18 November 2025 Pro Se Litigant Implied
Fabricated Case Law (2)
Misrepresented Case Law (1)
Warning
Jorge Paredes Guevara v. A&P Restaurant Corp., et al. S.D. New York (USA) 18 November 2025 Lawyer Implied
Fabricated Case Law (2)
False Quotes Case Law (1), Legal Norm (1)
Misrepresented Case Law (1)
In re Bryant M.D. North Carolina (Bankruptcy) (USA) 18 November 2025 Pro Se Litigant Implied
Fabricated Case Law (3)
False Quotes Case Law (1)
Misrepresented Case Law (1)
Show Cause Order
Kamia Nellum v. Credit Acceptance Corporation S.D. Indiana (USA) 18 November 2025 Pro Se Litigant Implied
Fabricated Case Law (1)
Misrepresented Case Law (1)
Warning
Source: Jesse Schaefer