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.
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 (211 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.)

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
Kheir v. Titan Team, The Money Source Inc., and Auction.com S.D. Texas (Bankruptcy) (USA) 4 November 2025 Lawyer Unidentified
Fabricated Case Law (3)
False Quotes Case Law (4)
Costs Order; 6 hours CLE on generative AI; provide order to client; Bar referral. 1 USD
Source: Robert Freund
Wertheimer v. Ryanair DAC Small Claims Court (Israel) 1 November 2025 Lawyer Implied
Fabricated Case Law (1)
Costs denied

The plaintiff, who is a lawyer , filed a claim for damages against Ryanair and included citations to several judgments to support his arguments. It was discovered that the plaintiff had used artificial intelligence to search for these judgments and/or draft the claim , and the cited cases "do not exist". The judge strongly condemned this conduct, stating it was improper and that the plaintiff's excuse for filing in haste was not acceptable. The non-existent citations were disregarded, and the court explicitly denied the plaintiff an award of costs (despite partially winning the claim) as a direct result of this conduct.

Mezu v. Mezu CA Maryland (USA) 29 October 2025 Lawyer ChatGPT
Fabricated Case Law (1)
False Quotes Case Law (1)
Misrepresented Case Law (1)
Referral to Attorney Grievance Commission
Source: Robert Freund
Joy Wilson v. KIPP Texas, Inc. N.D. Texas (USA) 29 October 2025 Lawyer ChatGPT
False Quotes Exhibits or Submissions (1)
Costs Order; 2h of CLE 1 USD
Source: Robert Freund
Robert Cole Stemkowski Goldman v. Arizona Board of Regents D. Arizona (USA) 29 October 2025 Lawyer Implied
Fabricated Case Law (1)
False Quotes Case Law (1)
Misrepresented Case Law (1)
Show Cause Order
Source: Jesse Schaefer
In re Jackson Hospital & Clinic, Inc., et al. M.D. Alabama (Bankruptcy) (USA) 28 October 2025 Lawyer Unidentified
Fabricated Case Law (1)
False Quotes Case Law (1)
Misrepresented Legal Norm (1)

Law firm explained what happened here. On October 28, 2025, the court declined to take any action in response to the motion for sanctions.

Green Building Initiative, Inc. v. Stephen R. Peacock & Green Globe Limited D. Oregon (USA) 27 October 2025 Lawyer Implied
Fabricated Case Law (2)
Show Cause Order
Source: Volokh
Crowder v. Yussman CA Kentucky (USA) 24 October 2025 Lawyer Implied
Fabricated Case Law (3)
Warning

" Moreover, we take this opportunity to caution practitioners of this Commonwealth on the submission of briefs or citations without confirming their accuracy and the correctness of the resulting analysis. The abject failure to conduct due diligence when making arguments to the Court greatly impacts the profession and undermines confidence in the skills and knowledge necessary to practice as an attorney. Failure to verify substantive legal citations prior to submission to this Court is not only in derogation of the RAP, but also violates the attorney's ethical responsibilities. See Supreme Court Rule 3.130(1.1).

Mistakes occur. Oversights happen. Those types of inadvertent errors we could absolve. However, purposelessly submitting a brief to a Court of law without confirming that the cited case law even exists is an affront to the dignity of the Court system, the legal profession as a whole, the judiciary, the client, and the public at large."

In re: Sanctions Order of Kenney CA Louisiana (USA) 23 October 2025 Lawyer ChatGPT, Microsoft Copilot, Google
Fabricated Case Law (3)
False Quotes Case Law (1)
Misrepresented Case Law (1)
Costs order, 3 hours CLE on ethical use of generative AI, referral to Office of Disciplinary Counsel 1368 USD
Mattox v. Product Innovation Research E.D. Oklahoma (USA) 22 October 2025 Lawyer ChatGPT
Fabricated Case Law (7)
False Quotes Case Law (2)
Misrepresented Case Law (3)
Pleadings struck; public reprimands; monetary sanctions; remedial filing and certification requirements 28495 USD

The Court found 28 false or misleading citations across 11 pleadings (14 fabricated, 14 erroneous/misquoted). Mr. Howie admitted use of ChatGPT and failure to verify citations. The Court applied Rule 11(b) and its AI framework (verification, candor/correction, accountability) and imposed sanctions and restitution. Fines of 3,000, 2,000, and 1,000 USD on individual attorneys, plus opposing party's costs and fees,

N-BAR Trade v. Amazon D.C. DC (USA) 22 October 2025 Lawyer Implied
Fabricated Case Law (1)
False Quotes Case Law (1)
Warning
Alexandria Jones v. DC Office of Unified Communications D.C. DC (USA) 22 October 2025 Lawyer Implied
False Quotes Case Law (1)
Warning
Mitchell Taylor Button et al. v. John Jimison W.D. Washington (USA) 17 October 2025 Lawyer Implied
Fabricated Case Law (2)
False Quotes Case Law (4)
Order include signed certification
Safe Choice, LLC v. City of Cleveland N.D. Ohio (USA) 17 October 2025 Lawyer Amicus (Casemine)
Fabricated Case Law (4)
Misrepresented Case Law (6)
Monetary Sanction; Referral to the Bar; Order to serve decision on clinet; 7500 USD

Order to show cause is here.

Gittemeier v. Liberty Mutual Personal Insurance Company E.D. Missouri (USA) 16 October 2025 Lawyer Implied
Fabricated Case Law (2)
Misrepresented Case Law (1), Doctrinal Work (1)
Show Cause Order

"One week after filing its second motion for summary judgment, Liberty Mutual submitted a notice of errata identifying the erroneous Goodman and Chaudri citations and demonstrating legitimate citations to those cases. [ECF No. 50].3 While the Court acknowledges Liberty Mutual’s prompt notice disclosing the two most serious errors in its filing, the additional misquotations and mischaracterizations discussed above will not be disregarded. Liberty Mutual indicates that the errors were typographical and/or caused by vision impairment, but that explanation is simply not credible. The errors in Liberty Mutual’s filing are not ones in which a few letters or numbers were passed over or shuffled. Rather, the filing includes entire names, dates, court designations, and Westlaw citations that are completely off base, and various other inaccuracies cannot be explained by typographical or vision issues. Therefore, the Court will reserve its ruling on the motion for sanctions and will set a hearing requiring Liberty Mutual to show cause why it should not be sanctioned."

Source: Volokh
Conrad Smith et al. v. Donald J. Trump et al. D.C. D.C. (USA) 16 October 2025 Lawyer Implied
Fabricated Legal Norm (1)
False Quotes Legal Norm (1)
Show Cause Order
YK v. The High State Prosecutor's Office in Prague) Supreme Administrative Court (Czech Republic) 15 October 2025 Lawyer Implied
Fabricated Case Law (1)
False Quotes Case Law (1)
Yasiel Puig Valdes v. All3Media America, LLC, et al. SCA California (Los Angeles) (USA) 15 October 2025 Lawyer ChatGPT
Fabricated Case Law (2)
Referral
Source: Volokh
Ric. n. 3054/2025 TAR Lombardia (Italy) 14 October 2025 Lawyer Unidentified
Fabricated Case Law (1)
Costs of 1,500 EUR, referral to the bar 1500 EUR
Source: LeggeZero
United States v. Glennie Antonio McGee S.D. Alabama (USA) 10 October 2025 Lawyer Ghostwriter Legal
Fabricated Case Law (1)
False Quotes Case Law (1)
Misrepresented Case Law (1)
Outdated Advice Overturned Case Law (1)
Public reprimand, referral and order to notify jurisdictions; monetary sanction 5000

Folllowing a show cause order, Counsel admitted to having used the tool together with Google Search, and explained that, although he was aware of the issues with AI models like ChatGPT, he said he did not expect this tool to fall into the same issues.

The Court found Attorney James A. Johnson used Ghostwriter Legal to draft a motion that contained multiple fabricated case citations, misstated/false quotations attributed to authorities, and cited precedent that had been reversed by the Supreme Court. The Court found the conduct tantamount to bad faith and imposed sanctions under its inherent authority. Sanctions include an order to file, not under seal, this order "in any case in any court wherein he appears as counsel fortwelve (12) months after the date of this order."

Roy J. Oneto v. Melvin Watson, et al. N.D. California (USA) 10 October 2025 Lawyer Implied
Fabricated Case Law (3)
Monetary Sanction, Order to notify client, complete CLE, and Bar informed 1000 USD
Lipe v. Albuquerque Public Schools (2) D. New Mexico (USA) 8 October 2025 Lawyer Implied
Fabricated Case Law (1)
Misrepresented Legal Norm (1)
Warning

The court noted prior fabricated citations in plaintiff's earlier briefing (for which counsel had already been sanctioned). In the current filing the court found no fabricated citations but identified inaccurate legal contentions—e.g., a rule statement claiming withholding ready-to-produce material while seeking extra time is sanctionable under Fed. R. Civ. P. 37(b)—which the court found unsupported and incorrect. The court suspected plaintiff used AI again, but simply removed the citations. The court admonished counsel to review AI-generated work and comply with Rule 11 but did not impose additional sanctions here.

14 Os 95/25i Oberster Gerichtshof (Austria) 7 October 2025 Lawyer Unidentified
Fabricated Case Law (1)
False Quotes Case Law (1)
Misrepresented Exhibits or Submissions (1)
Thomas Dexter Jakes v. Duane Youngblood W.D. Pennsylvania (USA) 6 October 2025 Lawyer Implied
False Quotes Case Law (8), Exhibits or Submissions (1)
Misrepresented Case Law (1)
Monetary Sanction; Pro Hac Vice status revoked 5000 USD

Original Show Cause Order is here.

Source: Volokh
AK v Secretary of State for the Home Department Upper Tribunal (UK) 6 October 2025 Lawyer ChatGPT
Fabricated Case Law (2)
Show Cause Order

The grounds of appeal contained at least two non-existent authorities. The judge concluded the false citations likely arose from unchecked generative-AI drafting and directed the solicitor to show cause why conduct should not be referred to the SRA.

Smith v. Athena Construction Group, Inc. D.C. DC (USA) 3 October 2025 Lawyer Grammarly; ProWritingAid
Fabricated Case Law (1)
False Quotes Case Law (4)
Misrepresented Case Law (4)
Costs Order; Order to notify Bar 1

Show Cause Order is available here.

Tovar v. American Automatic Fire Suppression Inc. SC California (USA) 3 October 2025 Lawyer implied
Fabricated Case Law (1)
Misrepresented Case Law (1)
Outdated Advice Repealed Law (1)
OSC/motion denied; no sanctions imposed.

Court denied OSC/motion on procedural safe-harbor grounds but found defendants submitted miscited, non-existent, and inapposite authorities (and noted risk of AI-generated fake citations). Defendants accepted responsibility but no sanctions imposed.

Source: Volokh
The People v. Raziel Ruiz Alvarez CA California (USA) 2 October 2025 Lawyer Unidentified
Fabricated Case Law (1)
False Quotes Case Law (1)
Misrepresented Case Law (1)
Published order; monetary sanction payable by Counsel (who withdrew); State Bar notified 1500 USD

"When criminal defense attorneys fail to comply with their ethical obligations, their conduct undermines the integrity of the judicial system. It also damages their credibility and potentially impugns the validity of the arguments they make on behalf of their clients, calling into question their competency and ability to ensure defendants are provided a meaningful opportunity to be heard. Thus, criminal defense attorneys must make every effort to confirm that the legal citations they supply exist and accurately reflect the law for which they are cited. That did not happen here."

Source: Volokh
Robenson Lafontant v. Coolidge-CLK St. Germaine E.D. Louisiana (USA) 2 October 2025 Lawyer Implied
Fabricated Case Law (1)
Misrepresented Case Law (1)
Monetary Sanction; 1h of CLE; Referral 1000 USD

Counsel admitted he did not verify citations. The court imposed a $1,000 sanction payable personally by counsel, ordered 1 hour CLE on generative AI, and referred him to the Disciplinary Committee.

In the Interest of R.A. CA Iowa (USA) 1 October 2025 Lawyer Unidentified
Fabricated Case Law (1)
False Quotes Case Law (1)
Brief struck; Monetary penalty OR two hours of AI-specific CLE; referral to Bar 150 USD
Ader v Ader SC New York (USA) 1 October 2025 Lawyer Unidentified
Fabricated Case Law (2)
False Quotes Case Law (1)
Misrepresented Case Law (1)
Costs Order; Referral to Bar Authorities 1

"This case adds yet another unfortunate chapter to the story of artificial intelligence misuse in the legal profession. Here, Defendants' counsel not only included an AI-hallucinated citation and quotations in the summary judgment brief that led to the filing of this motion for sanctions, but also included multiple new AIhallucinated citations and quotations in Defendants' brief opposing this motion. In other words, counsel relied upon unvetted AI—in his telling, via inadequately supervised colleagues—to defend his use of unvetted AI."

Family Law Case Ghent CA (Belgium) 1 October 2025 Lawyer Implied
Fabricated Case Law (1)
False Quotes Case Law (1)
Misrepresented Case Law (1)
Reprimand

Story available here.

Kertesz v. Colony Tire Corp et al. D. New Jersey (USA) 30 September 2025 Lawyer Unidentified
Fabricated Case Law (1)
False Quotes Case Law (1)
Warning

Plaintiff's counsel filed a Notice of Errata admitting that erroneous citation and quotation errors in multiple briefs resulted from the attorney's use of generative AI. The Court refused to consider the amended briefs/errata for purposes of its decision and treated any propositions supported solely by the incorrect or made-up citations as unsupported. The Court declined to impose sanctions but warned the attorney that relying on AI without proper oversight can be sanctionable under the New Jersey Rules of Professional Conduct.

Tajudin bin Gulam Rasul and another v Suriaya bte Haja Mohideen High Court (Singapore) 29 September 2025 Lawyer Unidentified
Fabricated Case Law (1)
Costs and order to inform client 800 SGD

CC cited a fictitious AI-generated case in written submissions. The Defendant's counsel located the error, CC admitted the authority was AI-generated and did not exist, and the Court found CC acted improperly, ordering personal costs of $800.

ANPV & SAPV v Secretary of State for the Home Department Upper Tribunal (UK) 29 September 2025 Lawyer Microsoft Copilot
Fabricated Case Law (2)
Misrepresented Case Law (4)
Show Cause Order
Reddy v Saroya CA Alberta (Canada) 26 September 2025 Lawyer Implied
Fabricated Case Law (1)

The appellant's original factum contained references to seven cases that could not be located (six allegedly decisions of this Court). Respondent flagged the issue; appellant's counsel ultimately acknowledged a contractor-drafted factum and that a large language model may have been used. The Court allowed an amended factum and reserved costs, warning that use of LLM without verification may attract costs, contempt proceedings, or Law Society referral.

Greenopolis Welfare Association (GWA) v. Narender Singh et al. Dehli High Court (India) 25 September 2025 Lawyer Unidentified
Fabricated Case Law (1)
False Quotes Case Law (1)
Petition withdrawn
Alexander Shaporov v. PIPPD P.O. Matthew Levine, et al. D. New Jersey (USA) 25 September 2025 Lawyer Implied
Fabricated Case Law (3)
False Quotes Case Law (1)
Misrepresented Case Law (2)
Show Cause Order

The district court independently found numerous inaccurate quotations and citations in Plaintiff's Opposition—misquoted language attributed to binding Third Circuit authority, Westlaw citations and dates that were incorrect or non-existent, and miscited pincites. The court concluded the pattern suggested the brief may have been prepared using generative AI without adequate verification and ordered counsel to show cause under Rule 11 and ethical rules. The court preserved the inaccuracies in the official opinion but removed links to invalid citations.

Beschluss 2-13 S 56/24 LG Frankfurt a. M. (Germany) 25 September 2025 Lawyer Unidentified
False Quotes Case Law (1)

Story available here.

Kenisha Black v. Mississippi DRS & Howard S.D. Mississippi (USA) 24 September 2025 Lawyer Unidentified
Fabricated Case Law (1)
Court accepted corrected briefs

Plaintiff's counsel admitted that the opening memorandum and reply brief contained false AI-generated content. Counsel filed corrected memoranda; the court noted a Rule 11 violation but accepted the corrections and declined to impose sanctions or require additional briefing.

Source: Jesse Schaefer
Puerto Rico Soccer League NFP, Corp., et al. v. Federación Puertorriqueña de Futbol, et al. D.C. Puerto Rico (USA) 23 September 2025 Lawyer Unidentified
Fabricated Case Law (6)
False Quotes Case Law (25)
Misrepresented Case Law (24)
Order to pay opposing counsel's fees 24492 USD

In the Order, the court stated: "A simple Google search would have shown the problems in some of Plaintiffs’ citations. In other instances, a quick search of the opinion Plaintiffs cited to would have revealed problems. Levying appropriate sanctions here promotes deterrence without being overly punitive, as contemplated by Rule 11(c)(4).

The Court notes that, rather than showing contrition, the Memorandum in Compliance strikes a defiant and deflective tone. (Docket No. 190). It also contains more of the errors that plagued Plaintiffs’ previous four filings. For example, in the “Legal Standard” section of the memorandum, Plaintiffs cite to two cases for the proposition that sanctions are an “extreme remedy” appropriate for instances of prejudice or bad faith. One case makes no mention of sanctions and neither contain the proffered quote Id. at 3. The Court finds it problematic that Plaintiffs responded to a show cause order to address the problem of multiple inaccurate citations by providing a response containing more erroneous citations."

Monetary sanction was decided in a subsequent decision dated 23 September 2025, available here.

Sentenza del 23.09.2025 Tribunale di Latina (Italy) 23 September 2025 Lawyer Unidentified
Fabricated Case Law (1)
Misrepresented Case Law (1)
Monetary Sanction 2000 EUR
Source: LeggeZero
Lipe v. Albuquerque Public Schools (1) D. New Mexico (USA) 22 September 2025 Lawyer Implied
Fabricated Case Law (3)
False Quotes Case Law (2)
Misrepresented Case Law (6)
Monetary sanction; self-report to state bars 3000 USD

Original Show Cause Order is here. Court noted that Counsel was still citing fabricated authorities, even though show cause proceedings are ongoing in parallel.

Vision Management Group v. Constant Aviation N.D. Ohio (USA) 22 September 2025 Lawyer Implied
Fabricated Case Law (2)
Warning, arguments disregarded
Gibralter v. DMS Flowers E.D. California (USA) 19 September 2025 Lawyer Unidentified
Fabricated Case Law (1)
Order to show cause discharged; Admonishment
Pelishek v. City of Sheboygan E.D. Wisconsin (USA) 18 September 2025 Lawyer Westlaw's Quick Check and AI Case Search Tool
Fabricated Case Law (1)
False Quotes Case Law (3)
Misrepresented Case Law (9), Exhibits or Submissions (4)
Monetary Sanction 4500 USD

Case involved counsel sanctioned in Coomer v. Lindell. In the OSC Order, the court noted:

"The fact that Kachouroff and DeMaster corrected some of their misrepresentations before the court or the defendants identified them would ordinarily mitigate their conduct. But the reality is that Kachouroff and DeMaster acted only after the Colorado District Court in Coomer v. Lindell noted similar misconduct. That so many misrepresentations persist supports the inference that counsel’s conduct was not mere negligence but an intentional effort to mislead the court."

In her response to the OSC (available here), Counsel disclosed the Westlaw tools she had used.

OTG New York, Inc. v. Ottogi America, Inc. D. New Jersey (USA) 18 September 2025 Lawyer Unidentified
Fabricated Case Law (1)
False Quotes Case Law (1)
Misrepresented Case Law (1)
Monetary sanction; Plaintiff's Reply withdrawn and stricken; order to self-report to bar(s) and serve client with order 3000 USD
Source: Robert Freund
Family law Case Gent (Belgium) 18 September 2025 Lawyer Implied
Fabricated Case Law (2), Doctrinal Work (1)
False Quotes Case Law (1), Legal Norm (2)
Misrepresented Legal Norm (2)
Disregarded all fictitious/unfindable sources, admonished counsel
R.G.L. n. 1018/2025 Tribunale di Torino (Italy) 16 September 2025 Lawyer Unidentified Misrepresented / incoherent and largely irrelevant jurisprudential and normative citations produced with AI support Monetary sanction 1500 EUR
Gabriel v. Mareco CA Buenos Aires (Argentina) 15 September 2025 Lawyer Implied
Fabricated Case Law (3)
Recurso de apelación declarado desierto; costas al apelante; se notificará al letrado y al Colegio de Abogados. No se impusieron sanciones profesionales.