Ko v. Li, 2025 ONSC 2766 (CanLII) and 2025 ONSC 2965 (CanLII)

Date: 2025-05-06, 2025-05-20

Docket: CV-25-00736891-00ES, FL Myers J

2025 ONSC 2766 CanLII | 2025 ONSC 2965 (CanLII)

“There had to be someone who was going to be the first lawyer to file AI hallucinations here. It was likely to be someone so junior as to over-estimate the infallibility of AI, or someone so senior as to not really yet understand its fallibility.” Justice Myers, Ko v. Li 2025 ONSC 2965 para. 73

In the case of Ko v. Li, 2025 ONSC 2766, Justice Myers of the Ontario Superior Court examined the risks of using generative artificial intelligence in litigation.

The issue arose during the course of an application regarding family law and estate matters. Counsel for the applicant delivered a factum referencing several reported decisions. Counsel referred to these cases in oral argument. Justice Myers was unable to locate the cases online and Counsel was unable to provide proper citations or hard copies of the cases. The factum also misstated the findings of a case reference. When asked if she had relied on generative AI in preparing her factum, Counsel advised the Court that it was not her usual practice to do so but that she would have to check with her clerk.

Justice Myers outlined the lawyer’s duty to faithfully represent the law to the court and to not mislead the court. In doing so, the lawyer has a duty to not fabricate case precedents, not mis-cite cases for propositions that they do not support, to use technology competently, to supervise staff, to review materials prepared by generative AI and read cases before relying on them in Court.

Counsel was ordered to show cause why she should not be cited for contempt of court.  She was directed to attend a scheduling case conference to discuss the process for the hearing.  At the scheduling conference [Ko v. Li, 2025 ONSC 2965] Counsel was forthright in admitting the reliance on generative AI without the requisite human verification for accuracy, she withdrew the factum, apologized, proposed a plan going forward to prevent the issue from happening again and committed to not bill her client for the research, factum writing and attendance at the motion. Justice Myers took judicial notice of the fact that the decision had garnered much attention in the press and that Counsel gained notoriety as a result.

The Court referenced the fact that Counsel failed to include the certification required by Rule 4.06.1 (2.1) of the Rules of Civil Procedure which was enacted to avoid this very issue:

(2.1) A factum shall include a statement signed by the party’s lawyer, or on the lawyer’s behalf by someone the lawyer has specifically authorized, certifying that the person signing the statement is satisfied as to the authenticity of every authority cited in the factum.

Justice Myers stated that it was not the use of AI itself that is the concern but rather it was the submissions of law made without first verifying that the authorities relied upon existed and supported the arguments made.

The Court found that a contempt hearing was no longer necessary as the scheduling conference accomplished the purpose of addressing contempt.  The Court listed the goals achieved: maintaining the dignity of the Court and the fairness of the civil justice system, promoting honourable behaviour by Counsel before the Court, denouncing serious misconduct, deterring similar future misconduct and rehabilitation. AI tools can enhance legal work but they must be used with competence and human supervision. This case serves as a reminder that lawyers have a duty to review all legal authorities that they are citing and relying upon and that they must remain vigilant when leveraging AI tools.