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 (978 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)
Heneghan v. The Owners, Strata Plan 187 BC CRT (Canada) 2 December 2025 Pro Se Litigant Implied
Fabricated Case Law (3)
Jarrus et al. v. Governor of Michigan et al. E.D. Michigan (USA) 2 December 2025 Pro Se Litigant ChatGPT Plus
Misrepresented Case Law (2)
Outdated Advice Repealed Law (1)
Monetary sanctions 1

"[T]he fact that Plaintiffs … did not "fabricate cases or cite nonexistent decisions" is of no help. When a case cite is "real," an attorney, or for that matter a judge, might see a case they recognize and assume the quote or holding has been accurately represented. That problem is illustrated here; although Chat GPT generated "holdings" that looked like they could plausibly have appeared in the cited cases, in fact it overstated their holdings to a significant degree. And while a litigant might get away with similar overstatements because they could, perhaps, reason their way to showing how a case's stated holding might extend to novel situations, an LLM does not reason in the way a litigant must.

To put it in a slightly different way, LLMs do not perform the metacognitive processes that are necessary to comply with Rule 11. LLMs are tools that "emulate the communicative function of language, not the separate and distinct cognitive process of thinking and reasoning." When an LLM overstates a holding of a case, it is not because it made a mistake when logically working through how that case might represent a "nonfrivolous argument for extending, modifying, or reversing existing law or for establishing new law;" it is just piecing together a plausible-looking sentence—one whose content may or may not be true."

Court later declined to reconsider this decision (see here).

In re: Avi Schwalb D. Colorado (Bankruptcy) (USA) 2 December 2025 Pro Se Litigant Implied
Fabricated Case Law (1)
Court rejected reliance on the citation
Magee v. New Balance Athletics, Inc. E.D. Arkansas (USA) 2 December 2025 Pro Se Litigant Unidentified
Fabricated Case Law (1)
False Quotes Case Law (1)
Misrepresented Case Law (1)
Brief Stricken; Order to Show Cause
Luis Alberto Contreras Fandinoe Tribunal Superior de Bogotá (Colombia) 2 December 2025 Judge Implied
Fabricated Case Law (1), Doctrinal Work (1)
Misrepresented Case Law (2)
Judgment quashed and remanded; copies sent to disciplinary commission.
A'Vard v Mornington Peninsula SC Victorian CAT (Australia) 2 December 2025 Pro Se Litigant Unidentified
Fabricated Case Law (2)
Peiman Shayan v. Ebby Shakib CA California (USA) 1 December 2025 Lawyer Implied
Fabricated Exhibits or Submissions (1)
False Quotes Case Law (1)
Misrepresented Case Law (1)
Brief struck; Monetary sanction; Bar Referral 7500 USD

"We disagree with respondent, however, that dismissing the appeal is an appropriate sanction for Farivar’s conduct. Our inherent authority to impose this sanction “should be exercised only in extreme situations, such as where the conduct was clear and deliberate and no lesser sanction would remedy the situation.” (Crawford v. JPMorgan Chase Bank, N.A. (2015) 242 Cal.App.4th 1265, 1271.) We conclude that we can sufficiently address the prejudice to the parties and the court from [Counsel]’s sanctionable conduct and sufficiently achieve the deterrent purpose of sanctions (see, e.g., Code Civ. Proc., § 128.7, subds. (b)(2), (c) & (h)) by doing the following:

First, [Counsel] shall pay sanctions in the amount of $7,500 to the clerk of this court within 30 days after the remittitur is filed. We calculate this amount based on, inter alia: (1) the significant amount of time this court spent verifying the fabricated citations in the opening brief, and (2) that Farivar refused to accept responsibility for his conduct, instead characterizing the fabricated quotations and citations as mere “clerical citation errors” and continuing to misrepresent legal authority in his opposition to the sanctions motion.

Second, we strike appellant’s opening brief and require appellant to file, within 10 days of the issuance of this order,a corrected opening brief. Appellant’s corrected brief may differ from the version originally filed only to the extent it corrects or omits the fabricated citations and quotations in the original version. Appellant shall file and serve both a final version of the new brief as well as a redline version.

Finally, because we conclude attorney Farivar has violated a Rule of Professional Conduct, we are required to “take appropriate corrective action.” (Cal. Code Jud. Ethics,canon 3D(2).) In line with this obligation, we direct the clerk of the court to serve a copy of this order on the State Bar.

We acknowledge and have considered that, as appellant argues, the majority of the fabricated quotes in the opening brief do not appear to be misrepresentations that work to appellant’s advantage; that is, the brief does not represent the law to be more favorable to appellant’s arguments than it actually is.

Nonetheless, we must consider broader concerns about the integrity of the courts and the legal profession. Inaccurate citations in briefing—whether the result of technological hallucinations or human failure to verify—may be relied on in court decisions, “circulated, believed, and become ‘fact’ and ‘law’ in some minds. We all must guard against those instances. . . . ‘There is no room in our court system for the submission of fake,10hallucinated case citations, facts, or law. . . . ’ [Citation.]” (Noland, supra, 114 Cal.App.5th at pp. 448-449.)"

Source: Robert Freund
Brick v. Gallatin County, et al. D. Montana (USA) 1 December 2025 Pro Se Litigant Implied
Fabricated Case Law (1)
Misrepresented Case Law (1)

Plaintiff repeatedly cited non-existent or misleading authorities in her Fourth Amended Complaint. The Court identified at least one fabricated citation and several mischaracterized cases, noting these failures to comply with Rule 8 and prior court instruction, and relied on the deficient pleadings in granting dismissal.

Ali Taj Bey v. Mark Glass M.D. Florida (USA) 1 December 2025 Pro Se Litigant Implied
Fabricated Case Law (1)
Warning
Kingdom of Sweden v. Samantha Ashhadi Soliman CA California (USA) 1 December 2025 Pro Se Litigant Implied
Fabricated Legal Norm (1)
False Quotes Case Law (2)
Misrepresented Case Law (2), Legal Norm (1)
Admonishment
Source: Jesse Schaefer
Lothamer Tax Resolution, Inc. v. Paul Kimmel (2) W.D. Michigan (USA) 1 December 2025 Pro Se Litigant Implied
Fabricated Case Law (3)
False Quotes Case Law (4)
Misrepresented Case Law (5)
Monetary Sanction

Show Cause Order is here.

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.