AI Hallucination Cases

Counsel confessed having Claude Sonnet 4 to draft a legal submission, which included fabricated quotations from legal authorities. Counsel said he was pressed by time.

After holding that there is "no reason to distinguish between the submission of fabricated cases and the submission of fabricated quotations from real cases. In both postures, the attorney seeks to persuade the Court using legal authority that does not exist", the court held that Mr. Desmarais had violated Rule 11 of the Federal Rules of Civil Procedure by failing to verify the accuracy of the AI-generated content. Counsel was found to have acted in subjective bad faith, as he was aware of the potential for AI to hallucinate legal citations and failed to take corrective action even after the government pointed out the errors.

The court imposed a $1,000 monetary sanction and required Counsel to complete a CLE course on the ethical use of AI in legal practice and notify his client of the issue.

Counsel tried to blame the software he used, as well as an intern; court was unimpressed

Prior Order to Show Cause available here.

After reviewing - and dismissing - the factual allegations made by Counsel, and noting that they had submitted errata in parallel cases (dealing with other fabricated citations), the court swiftly concluded that they "have violated Rule 11 because they were not reasonable in certifying that the claims, defenses, and other legal contentions contained in Defendants’ Opposition to Motion in Limine [Doc. 283] were warranted by existing law or by a nonfrivolous argument for extending, modifying, or reversing existing law or for establishing new law."

Both counsel were sanctioned with a 3,000 USD fine, payable to the court.

"Further, these inaccuracies signal that Plaintiff's counsel may have used AI to assist in the drafting of Plaintiff's Response (or otherwise counsel produced exceptionally sloppy work). In this regard, this Court's Chambers Rules include “Disclosure and Certification Requirements” for use of “Generative Artificial Intelligence” and expressly provide that an attorney or party must disclose in any document to be filed with the Court “that AI was used and the specific AI tool that was used” and to “certify in the document that the person has checked the accuracy of any portion of the document drafted by generative AI, including all citations and legal authority.” See id.6 No such disclosure and certification has been made in this case. The Court's Rules further provide that an attorney will be responsible for the contents of any documents prepared with generative AI, in accordance with Rule 11 of the Federal Rules of Civil Procedure, and that the failure to make the disclosure and certification “may result in the imposition of sanctions.”"

"In a prior order, we struck portions of Walker's brief that included citations to nonexistent cases. We note that the arguments raised would not have changed the outcome of the appeal in any event. "

Counsel in charge apologised to the Court in a letter (available here), explaining that he had failed to supervise the work of his subordinates.

"14    Here, the applicant's solicitor’s use of AI in the preparation of two court documents has given rise to cost, inconvenience and delay to the parties and has compromised the effectiveness of the administration of justice. But I do not consider the use of AI in this case means that it is appropriate to refer the solicitors’ conduct to the Victorian Legal Services Board. Here an inexperienced junior solicitor was given the task of preparing document citations for an amended pleading, and did so while working remotely and without access to the documents to be cited. In attempting to cite the relevant documents she used an (apparently AI-assisted) research tool which she considered had produced accurate citations when she previously used it. And as soon as Massar Briggs Law was told of the false citations the problem was addressed. The junior solicitor and the principal solicitor have apologised or expressed their regret to the other parties and the Court, and there was no suggestion that they were not genuine in doing so.

15    The junior solicitor took insufficient care in using Googe Scholar as the source of document citations in court documents, and in failing to check the citations against the physical and electronic copies of the cited documents that were held at Massar Briggs Law’s office. The error was centrally one of failing to check and verify the output of the search tool, which was contributed to by the inexperience of the junior solicitor and the failure of Mr Briggs to have systems in place to ensure that her work was appropriately supervised and checked. To censure those errors it is sufficient that these reasons be published."

Counsel for the claimant admitted to using an AI tool to draft the initial legal document without verifying its content. This resulted in the creation of non-existent judicial precedents to support the claimant's case. The court found this to be a serious violation of procedural loyalty and good faith, as it attempted to deceive the court and the opposing party. Consequently, the claimant was fined 5% of the updated value of the case for litigating in bad faith, although the lawyer's apologies were partially accepted, preventing a higher fine.

Fake citation, in this brief, was to : Moms Against Poverty v. Dep’t of State, 2022 WL 17951329, at *3 . Case docket can be found here.

Counsel later confirmed having used ChatGPT and apologised.

Counsel alleged that he only made a typo, but this did not convince the judges, who did not comment further.

" After the trial court entered a final judgment and decree of divorce, Nimat Shahid (“Wife”) filed a petition to reopen the case and set aside the final judgment, arguing that service by publication was improper. The trial court denied the motion, using an order that relied upon non-existent case law."

"We are troubled by the citation of bogus cases in the trial court's order. As the reviewing court, we make no findings of fact as to how this impropriety occurred, observing only that the order purports to have been prepared by Husband's attorney, Diana Lynch. We further note that Lynch had cited the two fictitious cases that made it into the trial court's order in Husband's response to the petition to reopen, and she cited additional fake cases both in that Response and in the Appellee's Brief filed in this Court. "

"[92] In Mavundla, the court emphasised the trite duty of legal practitioners not to mislead the court, whether through negligence or intent. This includes the duty to present an honest account of the law, which means (inter alia) not presenting fictitious or non-existent cases.24 In my view, it matters not that such cases were not presented orally, but were contained in written heads of argument. Written heads are as important a memorial of counsel’s argument as oral argument and, for purely practical reasons, are often more heavily relied upon by judges.

[...]

[95] In this case, counsel’s explanations bear out their submission that there was no deliberate attempt to mislead the court in relation to the use of incorrect case citations in the heads of argument. Their apologies are acknowledged. As is clear from Mavundla, however, even negligence in this context may have grave repercussions particularly to the administration of justice and, in appropriate circumstances, could constitute serious professional misconduct.

[96] As a consequence, it is appropriate to make the same order as in Mavundla, namely that the conduct of theapplicant’s legal practitioners is referred to the Legal Practice Council for investigation."

"Regarding the petitioner, this is a case of improper conduct, to say the least, on the part of its counsel (who apologized for it), who made use of artificial intelligence in the petition and in the supplementary argument, in which many non-existent and/or erroneous judgments were inserted and embedded. In accordance with the Supreme Court's ruling, there would have been grounds, as a result, for dismissing the petition outright, but I did not do so due to the conduct of the state, as detailed above, and due to the importance of publishing the tender. However, in this case, there is no place to award costs in favor of the petitioner, due to this improper conduct (as, beyond that, the petition also requested many remedies, some of which are not within the jurisdiction of this court)."

(Translation by Gemini 2.5.)

In the original order, the court held:

"[38] Applicants’ counsel provided further correspondence advising, for the first time, of his reliance on Visto.ai described as a professional legal research platform designed specifically for Canadian immigration and refugee law practitioners. He also indicated that he did not independently verify the citations as they were understood to reflect well established and widely accepted principles of law. In other words, the undeclared and unverified artificial intelligence had no impact, and the substantive legal argument was unaffected and supported by other cases.

[39] I do not accept that this is permissible. The use of generative artificial intelligence is increasingly common and a perfectly valid tool for counsel to use; however, in this Court, its use must be declared and as a matter of both practice, good sense and professionalism, its output must be verified by a human. The Court cannot be expected to spend time hunting for cases which do not exist or considering erroneous propositions of law.

[40] In fact, the two case hallucinations were not the full extent of the failure of the artificial intelligence product used. It also hallucinated the proper test for the admission on judicial review of evidence not before the decision-maker and cited, as authority, a case which had no bearing on the issue at all. To be clear, this was not a situation of a stray case with a variation of the established test but, rather, an approach similar to the test for new evidence on appeal. As noted above, the case relied upon in support of the wrong test (Cepeda-Gutierrez) has nothing to do with the issue. I note in passing that the case comprises 29 paragraphs and would take only a few minutes to review.

[41] In addition, counsel’s reliance on artificial intelligence was not revealed until after the issuance of four Directions. I find that this amounts to an attempt to mislead the Court and to conceal the reliance by describing the hallucinated authorities as “mis-cited” Had the initial request for a Book of Authorities resulted in the explanation in the last letter, I may have been more sympathetic. As matters stand, I am concerned that counsel does not recognize the seriousness of the issue."

In the final order, the court added:

"While the use of generative AI is not the responsibility of the responding party, it was not appropriate for the Respondent to not make any response to the Court’s four directions and Order. Indeed, assuming that the Respondent noticed the hallucinated cases on receipt of the written argument, it should have brought this to the attention of the Court.

[...]

Given that Applicant’s counsel was not remunerated for his services in the file, which included the motion on which the offending factum was filed and a motion for a stay of removal and, in addition, that I am also of the view that the Respondent’s lack of action exacerbated matters and it should not benefit as a result, I am ordering a modest amount of $100 to be payable by Applicant’s counsel personally."

Plaintiff's counsel in the case of Mintvest Capital, LTD v. NYDIG Trust Company, et al., was found to have included numerous non-existent cases, false quotations, and misrepresented precedents in their filings. The errors were attributed to the use of the AI tool 'Claude' without proper verification. The court recommended sanctions under Rule 11, requiring the attorney to pay the defendants' attorney fees related to the faulty submissions. The court emphasized the need for attorneys to ensure the accuracy of citations, especially when using AI tools, to maintain professional standards.

After other side pointed out that all authorities cited were fictitious, Counsel admitted it in brief. The court seemingly did not react.

Claimant used Chat GPT to assist in drafting his grounds of appeal and skeleton argument. The documents included fabricated citations and misrepresented case summaries. Claimant admitted to using Chat GPT and apologized for the errors.

Compounding matters, the court suspected that the respondent had also used AI, since the cases cited in the Counsel's skeleton, though extant, did not support any of the propositions made - and Counsel was unable to explain how they got there.

Counsel said that "The inclusion of inaccurate citations was inadvertent and the result of reliance on an automated legal citation tool."

"In Rutella's reply in support of his motion to vacate, he cites Green v. John H. Streater, Jr., 666 F.2d 119 (3d Cir. 1981). DE [69-1] at 8. When the Court was unable to locate Green or any case resembling it, the Court instructed Rutella's attorney, Kevin Krupnick, to either submit a copy of the case or show cause why he should not be sanctioned. See Electronic Order dated May 22, 2025. Krupnick admitted that he fabricated the Green case and claimed that he used it as a “placeholder” in a draft. DE [70-1]. It is implausible that an attorney would cite a case as specific as “Green v. John H. Streater, Jr., 666 F.2d 119 (3d Cir. 1981)” – which Krupnick admits does not exist – as a “placeholder” that he intended to replace. This is particularly true here, as Plaintiff had already cited the case that he subsequently claimed he intended to use. See DE [69-1] at 3 (citing Peralta v. Heights Med. Ctr., 485 U.S. 80 (1988)). Although Krupnick's conduct raises questions of his adherence to Fed. R. Civ. P. 11 (as he himself concedes), given the Court's recommendation that Rutella's motion to vacate be denied, the Court declines to recommend further action with respect to Rutella's misleading submission. "

"Regardless of whatever resources are used to prepare a party’s brief, every attorney has an ongoing responsibility to review and ensure the accuracy of filings with this and other courts. This includes checking that all case law cited in a brief actually exists and supports the points being made. It is never acceptable to rely on software or technology—no matter how advanced—without reviewing and verifying the information. The use of AI or other technology does not excuse carelessness or failure to follow professional standards.

Technology can be helpful, but it cannot replace a lawyer’s judgment, research, or ethical responsibilities. The practice of law changes with the use of new technology, but the core duties of competence and candor remain the same. Lawyers must adapt to new tools without lowering their standards."

In this rebuttal, the lawyer cited jurisprudence that the presiding judge (Relator) found to be "impressively so delineated and harmonious with the case". This prompted the judge to investigate the precedent more closely. He discovered that while the case number indicated was real, it belonged to a completely different case unrelated to the legal matter being discussed, leading to the suspicion of an AI "hallucination.

The court concluded:

"It is totally inconceivable to imagine that the Judiciary, already so burdened with countless lawsuits, needs to investigate all the case law set forth in the legal grounds reported by the parties in the procedural documents, despite the duty to act in good faith set forth in Article 5 of the CPC. After all, it is entirely based on the principle of trust expectation that all subjects act in accordance with existing and valid rules.

Thus, even if the appellant claims that such conduct was the result of an error, a claim that has not been satisfactorily proven, but which is taken as a premise for the purposes of argumentation, in the present case, it would be, at the very least, an inexcusable, gross error resulting from serious misconduct, ruling out the possibility of proceeding without any implications in this judicial field, so as not to allow any hesitation in considering the aforementioned conduct as being clearly litigious in bad faith.

Thus, as a result of having acted in a manifestly reckless manner (Art. 80, V of the CPC), I condemn the appellant for litigation in bad faith, and he must pay the fine set at 1% of the value of the case (Art. 81 of the CPC), in accordance with the grounds"

Translated with DeepL.com (free version)

The appellant, a lawyer representing himself in an appeal, submitted a brief that included non-existent legal citations. An employee in the lawyer's office had used an AI system to assist in drafting the document. After the opposing counsel and the court itself were unable to locate the cited precedents, the lawyer admitted they were AI-generated and a "good-faith mistake" for which he took full responsibility. While citing its authority to dismiss the appeal entirely due to the submission of non-existent sources, the court chose a "softer" sanction. It proceeded to hear the case, ultimately dismissing the appeal on its merits and imposing a separate monetary penalty payable to the State Treasury for the misconduct.

This judgment, delivered on 6 June 2025 by the Divisional Court of the King's Bench Division, addresses two cases referred under the court's Hamid jurisdiction, which concerns the court's power to enforce duties lawyers owe to the court. Both cases involve lawyers submitting written arguments or evidence containing false information, specifically non-existent case citations, generated through the use of artificial intelligence without proper verification.

The Court used this opportunity to issue broader guidance on the use of AI in legal practice, raising concerns about the competence, training, and supervision of lawyers.

Court noted that Counsel was still citing fabricated authorities, even though show cause proceedings are ongoing in parallel.

AI Use

Attorneys for Wright County submitted a memorandum in support of a motion for summary judgment that contained five case citations generated by artificial intelligence; these citations did not refer to actual judicial decisions. Much of the brief appeared to be AI-written. The attorney who signed and filed the brief, acknowledged that the cited authorities did not exist and that much of the brief was drafted by AI.

Ruling/Sanction

The Court found Counsel's conduct violated Rule 11.02(b) of the Minnesota Rules of Civil Procedure, as fake case citations cannot support any legal claim and there's an affirmative duty to investigate the legal underpinnings of a pleading. The Court found no merit in Counsel's defense, noting that the substitute cases she offered did not support the legal contentions in the brief, and the brief demonstrated a fundamental misunderstanding of legal standards. The Court did not find her insinuation that another, accurate motion document existed to be credible.

Although the Court considered summarily denying the County's motion as a sanction, it ultimately denied the motion on its merits in a concurrent order because the arguments were so clearly incorrect.

The Court declined to order further monetary sanctions, believing its Order to Show Cause and the current Order on Sanctions were sufficient to deter Counsel from relying solely on AI for case citations or legal conclusions in the future. However, the Court referred the matter concerning Counsel's conduct to the Minnesota Lawyers Professional Responsibility Board for further review, as the submission of an AI-generated brief with fake citations raised questions regarding her honesty, trustworthiness, and fitness as a lawyer.

The underlying motion was later withdrawn, with the result that the tentative ruling was not adopted.

(Earlier report and recommendation can be found here.)

AI Use

Counsel admitted at a show cause hearing that he used generative AI tools to draft multiple briefs and did not verify the citations provided by the AI, mistakenly trusting their apparent credibility without checking.

Hallucination Details

Three distinct fake cases across filings. Each was cited in a separate brief, with no attempt at Shepardizing or KeyCiting.

Ruling/Sanction

The Court recommended a $15,000 sanction ($5,000 per violation), with the matter referred to the Chief Judge for potential additional professional discipline. Counsel was also ordered to notify Hoosiervac LLC’s CEO of the misconduct and file a certification of compliance.

Eventually, the court fined Counsel $6,000, stressing that this was sufficient.

Key Judicial Reasoning

The judge stressed that "It is one thing to use AI to assist with initial research, and even nonlegal AI programs may provide a helpful 30,000-foot view. It is an entirely different thing, however, to rely on the output of a generative AI program without verifying the current treatment or validity—or, indeed, the very existence—of the case presented. Confirming a case is good law is a basic, routine matter and something to be expected from a practicing attorney. As noted in the case of an expert witness, an individual's "citation to fake, AI-generated sources . . . shatters his credibility." See Kohls v. Ellison, No. 0:24-cv-03754-LMP-DLM, Doc. 46 at *10 (D. Minn. Jan. 10, 2025)."

(Order to show cause is here.)

Hallucination Details

The applicant’s factum included citations to:

• Alam v. Shah, which linked to an unrelated case (Gatoto v. 5GC Inc.)
• DaCosta v. DaCosta, which returned a 404 error
• Johnson v. Lanka, cited for a proposition directly contradicted by the decision
• Meschino Estate v. Meschino, which actually linked to a wrongful dismissal case (Antonacci v. Great Atlantic & Pacific Co.)

The judge noted these citations bore “hallmarks of an AI response” and described the conduct as possibly involving “hallucinations” from generative AI. The court ordered counsel to appear to explain whether she knowingly relied on AI and failed to verify the content. No clarification or correction was received from counsel after the hearing.

Ruling/Sanction

At the end of the show cause proceedings, Justice Myers noted that, due to the media reports about this case, the goals of any further contempt proceedings were already met, including: "maintaining the dignity of the court and the fairness of civil justice system, promoting honourable behaviour by counsel before the court, denouncing serious misconduct, deterring similar future misconduct by the legal profession, the public generally, and by Ms. Lee specifically, and rehabilitation".

The judge therefore declined to impose a fine or to continue the contempt proceedings, on the condition that Counsel undertakes Continuing Professional Development courses (as she said she would), and does not bill her client for any unrelated work (which was helped by the fact that she had so far been working pro bono).

AI Use

Counsel admitted that incorrect citations arose from reliance on an AI-enabled database called “Takdin AI.” The tool generated incorrect references to multiple Supreme Court decisions and falsely cited them as supporting key propositions. Counsel claimed the errors stemmed from time pressure and good faith, but the Court found the explanation inadequate.

Hallucination Details

At least 8 citations were found to be fictitious or unrelated to the argument, including:

• Afriedar v. Rosh HaAyin Municipality (Ra'ava 6774/19), which had been overturned and clearly marked as such
• Phoenix v. Avital and Novartis decisions, which were either non-existent or misquoted
• References to non-existent sections of the Civil Procedure Regulations and the Class Actions Law

The hallucinated citations were used in response to motions to dismiss and as the basis for substantive legal claims in the class certification request.

Ruling/Sanction

The Court:

• Struck the class certification request due to cumulative procedural abuses and AI hallucinations
• Explicitly ruled that the applicant's counsel is not suitable to serve as representative counsel in this proceeding or any similar one filed in its place
• Imposed monetary fines: (i) The Mahala Association was ordered to pay NIS 10,000 to each of the four respondents (totaling NIS 40,000); Counsel was ordered to pay personal costs: NIS 5,000 to the first respondent (Clalit) and NIS 5,000 to the State Treasury (totaling NIS 10,000).

Key Judicial Reasoning

The Court emphasized that the inclusion of hallucinated sources—regardless of intent—subverted proper legal process. Citations must be verified, and AI does not absolve attorneys from professional responsibility. The systemic risks posed by hallucinated filings necessitate a firm response going forward

The Family Court noted that one motion cited case law that does "not exist at all". This raised "concern about uncontrolled use of artificial intelligence technology," referencing recent Supreme Court guidance on the need for an appropriate judicial response to such instances.

On appeal, the District Court acknowledged the Family Court's finding regarding the non-existent case law and the suspicion of AI use. However, like the Family Court, it did not impose a separate sanction for this, as the appeal was dismissed primarily on the grounds of the delay and lack of merit concerning the protocol correction itself

AI Use

The fabricated citations originated from a ChatGPT query submitted by an unlicensed law clerk at Petitioner's law firm. Neither Counsel reviewed the petition’s contents before filing. The firm had no AI use policy in place at the time, though they implemented one after the order to show cause was issued.

Hallucination Details

Chief among the hallucinations was Royer v. Nelson, which Respondents demonstrated existed only in ChatGPT’s output and in no official database. Other cited cases were also inapposite or unverifiable. Petitioner’s counsel admitted fault and stated they were unaware AI had been used during drafting.

Ruling/Sanction

The court issued three targeted sanctions:

• Attorney fees: Respondents’ counsel are to submit an itemized bill; Counsel must pay within 10 days of receipt
• Client refund: Petitioner’s counsel must refund all fees paid by Mr. Garner in relation to the defective petition
• Charitable payment: Counsel must donate $1,000 to “and Justice for all” within 14 days and file proof of payment with the court

Key Judicial Reasoning

The panel (Per Curiam) emphasized that the conduct, while not malicious, still diverted judicial resources and imposed unnecessary burdens on the opposing party. Unlike Mata or Hayes, the attorneys in this case quickly admitted the issue and cooperated, which the court acknowledged. Nonetheless, the submission of fabricated law—especially under counsel's signature—breaches core duties of candor and verification, warranting formal sanctions. The court warned that Utah’s judiciary cannot be expected to verify every citation and must be able to trust lawyers to do so

AI Use

First Counsel, who had not previously used AI for legal work, used an unspecified AI tool to assist with drafting a response. He failed to verify the citation before submission. Second Counsel, as local counsel, filed the response without checking the content or accuracy, even though he signed the document.

Second Counsel then said that he had initiated "procedural safeguards to prevent this error from happening again by ensuring he, and local counsel, undertake a comprehensive review of all citations and arguments filed with this and every court prior to submission to ensure their provenance can be traced to professional non-AI sources."

Hallucination Details

The hallucinated case was cited as controlling Delaware authority on privilege assignments. When challenged by Plaintiff, Defendants initially filed a bare withdrawal without explanation. Only upon court order did they disclose the AI origin and acknowledge the error. Counsel personally apologized to the court and opposing counsel.

Ruling/Sanction

Judge William Matthewman imposed a multi-part sanction:

• Attorneys’ fees and costs incurred by Plaintiff in rebutting the hallucinated citation—jointly payable by Counsel
• Required CLE on AI ethics within 30 days, with proof of completion due by June 20, 2025
• Monetary fines: $1,000 (First Counsel) and $500 (Second Counsel), payable to the Court registry

The Court emphasized that the submission of hallucinated citations—particularly when filed and signed by two attorneys—constitutes reckless disregard for procedural and ethical obligations. Though no bad faith was found, the conduct was sanctionable under Rule 11, § 1927, the Court’s inherent authority, and local professional responsibility rules.

Key Judicial Reasoning

The Court distinguished this case from more egregious incidents (O’Brien v. Flick, Thomas v. Pangburn) because the attorneys admitted their error and did not lie or attempt to cover it up. However, the delay in correction and failure to check the citation in the first place were serious enough to warrant monetary penalties and educational obligations.

AI Use

Counsel filed a motion to dismiss appeal that cited “Greenspan v. Greenspan, 121 Hawai‘i 60, 71, 214 P.3d 557, 568 (App. 2009).” The court found that:

• No Hawai‘i case titled Greenspan v. Greenspan exists
• The citations to “121 Hawai‘i 60” and “214 P.3d 568” were in fact to other real cases (Estate of Roxas v. Marcos and Colorado Court of Appeals cases), suggesting a garbled AI-generated fabrication
• Counsel admitted delegating the brief to a per diem attorney and failing to verify the citation before filing

Ruling/Sanction

• $100 sanction imposed on counsel personally
• Payment to be made to the Supreme Court Clerk of Hawai‘i within seven days
• DiPasquale ordered to file a declaration attesting to payment.

The amount reflects counsel’s candor and corrective measures, but the court noted that federal courts have imposed higher sanctions in similar cases.

AI Use

The plaintiff, proceeding pro se, cited “Darling v. Linde, Inc., No. 21-cv-01258, 2023 WL 2320117 (D. Or. Feb. 28, 2023)” in briefing. The court stated it could not locate the case in any major legal database or via internet search and noted this could trigger Rule 11 sanctions if not based on a reasonable inquiry. The ruling cited Saxena v. Martinez-Hernandez as a cautionary example involving AI hallucinations, suggesting the court suspected similar conduct here.

Counsel later explained how the motion came to be: see here.

AI Use

In a filing related to a third-party notice, the defendant cited a judgment that did not exist. The judge clarified that this was not simply a mistaken citation or party confusion, but rather a reference to an entirely fictional judgment. The court explicitly stated: “It is not clear how such an error occurs, except through the use of artificial intelligence.”

Ruling/Sanction

The court permitted the defendant to proceed with the third-party notice but ordered partial costs (₪1,200) to be paid to the plaintiff due to procedural irregularities. The judge demanded a formal explanation of how the fictitious citation was introduced, in order to prevent recurrence

Key Judicial Reasoning

While the procedural error did not warrant barring the defendant’s claim against a third party, the court emphasized that referencing a fictional legal source is a serious issue requiring scrutiny. The opinion signals a growing judicial intolerance for unverified AI-assisted legal drafting in Israeli courts.

AI Use

The petition’s pages were marked “Criado com MobiOffice.” The STF verified that MobiOffice includes a built-in AI writing assistant. Combined with the inclusion of fictitious citations, this led the Court to conclude that AI had been used and not reviewed. The judge characterized this as reckless conduct.

Hallucination Details

• Claimed violations of STF precedents including RE 464.867/SP and RE 226.855/RS, which were either inapplicable or misrepresented
• Claimed Súmula Vinculante 6 said something entirely false (its actual content concerns military service remuneration)
• Cited judgments ARE 1.218.084 AgR and RE 328.111/DF as relevant when they were either misquoted or irrelevant
• Court concluded these references were invented or misrepresented, “false statements intended to mislead”

Ruling/Sanction

• Rejected the complaint as manifestly inadmissible
• Found that counsel likely used AI and submitted the petition without review
• Ordered notification to both the national and Bahia sections of the OAB
• Declared the petitioner litigated in bad faith under Article 80, V, of the Brazilian Civil Procedure Code
• Imposed a procedural penalty of double the initial court costs
• Ordered referral to dívida ativa (federal collections) if not paid.

AI Use

Counsel explained that the hallucinated citations were included in a draft intended for personal legal research and learning, which was mistakenly filed with the court. This constituted an implicit admission that generative AI tools were involved.

Ruling/Sanction

While Judge Itay Katz did not impose personal costs, he referred the matter to the Legal Department of the Judicial Authority to determine whether further steps—including referral to the Israel Bar Association Ethics Committee—should be taken. The court emphasized this was done as a gesture of leniency with the hope that such behavior will not recur.

Key Judicial Reasoning

The court referred to several other recent Israeli cases to underscore the growing recognition of AI hallucination risk in legal practice. It reiterated the requirement for attorneys to meticulously verify any citation before submission and warned that future similar instances may not receive such lenient treatment.

The STF relator found that the petition relied on decisions that could not be located and contained false statements about the content of Súmula Vinculante n.º 6 and other precedents. The petition bore a 'Criado com MobiOffice' watermark and the relator concluded the author likely used an AI writing assistant without review. The complaint was denied, bad faith was declared and procedural costs were doubled; OAB was notified.

(Grievance Committee Report available here.)

AI Use

Neusom told the grievance committee that he “may have used artificial intelligence” in preparing filings, and that any hallucinated cases were not deliberately fabricated but may have come from AI tools. The filings in question included a notice of removal and a motion for summary judgment. The judge later noted a pattern of citations inconsistent with established case law and unsupported by known databases.

Hallucination Details

Citations included cases that either did not exist or were grossly mischaracterized. Notably:

• Southern Specialties, Inc. v. Pulido Produce, Inc. – no such case found in Westlaw, Lexis, or PACER
• Trilogy Communications v. Times Fiber – cited in support of breach of contract when it was a patent matter involving no such principles

Neusom failed to produce the full texts of the cited cases when requested and instead filed a 721-page exhibit in violation of court orders.

Ruling/Sanction

The court adopted the grievance committee’s recommendation and imposed a one-year suspension. Neusom is prohibited from accepting new federal cases in the Middle District of Florida during the suspension and must:

• Notify existing clients and the court of his suspension
• File a compliance affidavit within 30 days
• Complete appropriate CLE and counseling programs
• Remain in good standing with the Florida Bar
• Apply for reinstatement only after certifying compliance

Key Judicial Reasoning

The court found that Neusom violated Rules 4-1.3, 4-3.3(a)(3), 4-3.4(c), and 4-8.4(c) of the Florida Rules of Professional Conduct. His failure to verify AI-generated content, compounded by noncompliance with orders and false statements to opposing counsel, demonstrated a pattern of recklessness and dishonesty. The court emphasized that federal proceedings require a high standard of diligence and that invoking AI cannot excuse failure to meet professional obligations.

AI Use

Counsel used CoCounsel, Westlaw’s AI tools, and Google Gemini to generate a legal outline for a discovery-related supplemental brief. The outline contained hallucinated citations and quotations, which were incorporated into the filed brief by colleagues at both Ellis George and K&L Gates. No one verified the content before filing. After the Special Master flagged two issues, counsel refiled a revised brief—but it still included six AI-generated hallucinations and did not disclose AI use until ordered to respond.

Hallucination Details

At least two cases did not exist at all, including a fabricated quotation attributed to Booth v. Allstate Ins. Co., 198 Cal.App.3d 1357 (1989). Misquoted or fabricated quotes attributed to National Steel Products Co. v. Superior Court, 164 Cal.App.3d 476 (1985). Several additional misquotes and garbled citations across three submitted versions of the brief. Revised versions attempted to silently “fix” errors without disclosing their origin in AI output.

Ruling/Sanction

The Special Master (Judge Wilner) struck all versions of Plaintiff’s supplemental brief, denied the requested discovery relief, and imposed:

• $26,100 in fees to reimburse Defendant for Special Master costs
• $5,000 in additional attorney’s fees to Defendant
• Total monetary sanction: $31,100, payable jointly and severally by Ellis George LLP and K&L Gates LLP
• No sanctions against individual attorneys due to candid admissions and remedial action, but strong warning issued

Key Judicial Reasoning

The submission and re-submission of AI-generated material without verification, especially after warning signs were raised, was deemed reckless and improper. The court emphasized that undisclosed AI use that results in fabricated law undermines judicial integrity. While individual attorneys were spared, the firms were sanctioned for systemic failure in verification and supervision. The Special Master underscored that the materials nearly made it into a judicial order, calling that prospect “scary” and demanding “strong deterrence.”