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 (135 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 have any questions about the database, a FAQ is available here.
And 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)
J.V.E.C. v S.M.D. KB Saskatchewan (Canada) 4 December 2025 Pro Se Litigant Implied
Fabricated Case Law (1)
Source: Courtready
Heneghan v. The Owners, Strata Plan 187 BC CRT (Canada) 2 December 2025 Pro Se Litigant Implied
Fabricated Case Law (3)
Internet Sciences Inc v CNSX Markets Inc CMT Ontario (Canada) 1 December 2025 Pro Se Litigant Implied
Fabricated Legal Norm (1)
Misrepresented Legal Norm (1)
Warning
Source: Courtready
Wang, Fengxi (Re) Ontario SCJ (Canada) 1 December 2025 Pro Se Litigant Implied
Fabricated Case Law (4)
Admonishment
Source: Courtready
Obermann v. Spring Financial Inc. BC CRT (Canada) 28 November 2025 Pro Se Litigant Implied
Fabricated Case Law (1)
Misrepresented Legal Norm (1)
PL v Minister of Employment and Social Development Social Security Tribunal (Canada) 28 November 2025 Pro Se Litigant Implied
Fabricated Case Law (2)
Source: Courtready
Chan v. British Columbia CA British Columbia (Canada) 28 November 2025 Pro Se Litigant Implied
Fabricated Case Law (1)
Lessard c. Longuépée Québec (Canada) 26 November 2025 Pro Se Litigant ChatGPT
Fabricated Case Law (4)
Warning
In re Robert Giroux CS Québec (Canada) 26 November 2025 Judge Implied
Fabricated Case Law (1)
Currently pending appeal

Story here.

⚠ Alleged AI Use
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
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."

R v Wallace KB New Brunswick (Canada) 20 November 2025 Pro Se Litigant Implied
Fabricated Case Law (1)
RR v. Fraser Health Authority and others (No.3) British Columbia HRT (Canada) 20 November 2025 Pro Se Litigant Implied
Fabricated Case Law (1)
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
Wang v. Mongeon HRT Ontario (Canada) 19 November 2025 Pro Se Litigant Implied
Fabricated Case Law (3)
Small Moves Canada Inc. v. Garner BC CRT (Canada) 18 November 2025 Lawyer Implied
Fabricated Legal Norm (1)
Tribunal found the cited 'British Columbia Fraudulent Transactions Act' does not exist and declined to consider or add fraud claims based on it.
Azar c. Université de Montréal Quebec CA (Canada) 13 November 2025 Pro Se Litigant Implied
Fabricated Case Law (1)
Source: Courtready
Choi v. Slopinski SC British Columbia (Canada) 10 November 2025 Pro Se Litigant Implied
Fabricated Case Law (1)
BC Taco Restaurant Group Ltd. BC Employment Standards Tribunal (Canada) 6 November 2025 Lawyer Implied
Fabricated Case Law (1)
S… F… c. I… O… Québec SC (Canada) 31 October 2025 Pro Se Litigant ChatGPT
Fabricated Case Law (1)
Misrepresented Legal Norm (1)
Warning
Source: Courtready
O.K. v. Southern Ontario Secondary Schools Association Human Rights Tribunal of Ontario (Canada) 30 October 2025 Lawyer Implied
Fabricated Case Law (1)
Bourse de l'Immobilier Multilogements inc. c. Lanthier CS Québec (Canada) 29 October 2025 Pro Se Litigant ChatGPT
Fabricated Case Law (3)
Monetary sanction 750 CAD
The Vancor Group Inc. v. 2744364 Ontario Limited et al Ontario SCJ (Canada) 28 October 2025 Pro Se Litigant Unidentified
Fabricated Case Law (1), other (1)
Misrepresented Case Law (1)
Admonishment
Wu v. Murray CA British Columbia (Canada) 21 October 2025 Pro Se Litigant Unidentified
Fabricated Case Law (2)
Costs order took hallucinations into account
X.L. v. Z.L. et al Ontario SCJ (Canada) 16 October 2025 Pro Se Litigant Implied
Fabricated Case Law (2)
Misrepresented Case Law (6)
No reliance on authorities submitted; Monetary Sanction 1000 CAD

Costs were awarded here.

T.B. v K.M. King's Bench for Saskatchewan (Canada) 15 October 2025 Pro Se Litigant Implied
Fabricated Case Law (5)
Court declined to award costs to applicant; portions of the reply brief were struck; admonishment
Gilles Dulac c. Ville de Gatineau TA Québec (Canada) 11 October 2025 Pro Se Litigant Implied
Fabricated Case Law (5)
Source: Courtready
Visca v. Halton District School Board HRT Ontario (Canada) 9 October 2025 Pro Se Litigant Implied
Fabricated Case Law (3)
Ren v. Area 09 BCPAAB (Canada) 7 October 2025 Pro Se Litigant Implied
Fabricated Case Law (2)
Misrepresented Doctrinal Work (1)
Breach of Board's Code of Conduct 910 CAD

(Monetary sanction decided in later determination, available here.)

Delisle v. Canadian Association of Professional Employees FPSLREB (Canada) 3 October 2025 Pro Se Litigant Implied
Fabricated Case Law (1)
Misrepresented Case Law (1)
Backhaus v. Area 01 BC Property Assessment Appeal Board (Canada) 2 October 2025 Pro Se Litigant Implied
Fabricated Case Law (2)
Warning

The appellant cited two reported decisions which the Board could not locate and concluded likely do not exist and may have been generated with AI; the Board excluded those authorities from evidence and cautioned the appellant about nondisclosure of AI per the Board's Code of Conduct.

Specter Aviation Limited v. Laprade CS Québec (Canada) 1 October 2025 Pro Se Litigant Unidentified
Fabricated Case Law (1)
Monetary sanction for procedural misconduct 5000 CAD

Monsieur Laprade filed a contestation containing multiple citations to non-existent authorities generated with the assistance of artificial intelligence. The Court found these to be fabricated (so-called "hallucinated") citations, constituting a manquement important to the conduct of the proceeding under art. 342 C.p.c., and imposed a 5,000$ sanction.

Hogan v. Treasury Board Federal PSLREB (Canada) 1 October 2025 Pro Se Litigant Implied
Fabricated Case Law (4), Doctrinal Work (1)
False Quotes Legal Norm (1)
Misrepresented Case Law (3)
Outdated Advice Repealed Law (1)
Reddy v Saroya CA Alberta (Canada) 26 September 2025 Lawyer Implied
Fabricated Case Law (1)
Adverse Costs Order 17550 CAD

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.

Monetary sanction was determined in a subsequent decision (available here).

Salem v. Deputy Head Federal PSLREB (Canada) 24 September 2025 Pro Se Litigant Implied
Fabricated Case Law (4)
Misrepresented Case Law (1)
Stile Carpentry Ltd. v. 2004424 Ontario CA Ontario (Canada) 23 September 2025 Pro Se Litigant Implied
Fabricated Case Law (1), Exhibits or Submissions (1), Legal Norm (1)
False Quotes Case Law (1)
Misrepresented Case Law (1)
Régie du bâtiment du Québec c. 9308-2469 Québec inc. Régie du bâtiment du Québec (Canada) 11 September 2025 Pro Se Litigant ChatGPT
Fabricated Case Law (1), Legal Norm (1)
Disregarded AI-generated arguments
Re X Corp. BC Civil Resolution Tribunal (Canada) 4 September 2025 Pro Se Litigant Unidentified
False Quotes Case Law (1)
Misrepresented Case Law (1)
Claim for compensation dismissed due to false and misleading AI-assisted submissions
Source: Steve Finlay
Lockwood v. ICBC BC Civil Resolution Tribunal (Canada) 3 September 2025 Pro Se Litigant Implied
Fabricated Legal Norm (2)
Argument ignored
Alana Kotler v Ontario Secondary School Teachers’ Federation Ontario Labour Relations Board (Canada) 29 August 2025 Pro Se Litigant Implied
Fabricated Case Law (14)
Misrepresented Case Law (1)
Arguments ignored

The applicant relied on numerous case citations that the Board and OSSTF could not locate as cited; one located decision did not support the proposition relied upon. Applicant acknowledged possible citation errors and was asked to provide copies but objected. The Board refused to rely on unlocatable authorities and dismissed the application.

Myers v. Tarion Warranty Corporation Ontario (Canada) 28 August 2025 Pro Se Litigant Implied
Fabricated Case Law (1)
False Quotes Case Law (1)
Misrepresented Case Law (1)
Arguments ignored
MacEachern-Flatt v. University Health Network HRT Ontario (Canada) 25 August 2025 Pro Se Litigant Implied
Fabricated Case Law (1)
Babbar v. Tarion Warranty Corporation LAT Ontario (Canada) 25 August 2025 Pro Se Litigant Implied
Fabricated Case Law (2)
Source: Courtready
WCAT Decision A2501051 (Hilary Thomson) BC Workers' Compensation Appeal Tribunal (Canada) 18 August 2025 Pro Se Litigant Implied
Fabricated Case Law (2)
Misrepresented Case Law (1)
Outdated Advice Repealed Law (1)
XH v Canada Employment Insurance Commission Social Security Tribunal (Canada) 18 August 2025 Pro Se Litigant Implied
Fabricated Case Law (1)
Warning
Source: Courtready
Maxwell v. WestJet Airlines Ltd. Civil Resolution Tribunal (Canada) 15 August 2025 Pro Se Litigant ChatGPT
Fabricated Case Law (1)
Misrepresented Exhibits or Submissions (1)
Outdated Advice Repealed Law (1)
Argument given no weight
Source: Steve Finlay
Yashcheshen v. Saskatchewan Government Insurance KB Saskatchewan (Canada) 15 August 2025 Pro Se Litigant Implied
False Quotes Case Law (1)
Source: Courtready
Blinds to Go Inc. c. Blachley Quebec SC (Canada) 11 August 2025 Pro Se Litigant Implied
Fabricated Case Law (4)
Musselman v. Vanderstelt CA British Columbia (Canada) 8 August 2025 Pro Se Litigant Implied
Fabricated Case Law (2)
Weighed in deciding to grant security for trial costs