Landberg v. City of New York
Supreme Court of the State of New York, Appellate Division, Second Department · N.Y. App. Div. 2d Dep't · New York bar guidance
Conduct
Appellate brief cited or quoted three fictitious cases, including a fake Court of Appeals quotation contrary to actual law; counsel was not candid at argument.
Consequence
$8,000 against the attorney and $2,500 against the firm, both payable to the Lawyers' Fund for Client Protection.
Lesson
A firm whose name is on the brief can be sanctioned alongside the drafting lawyer, even where the court credits that he acted against firm policy.
Verified September 28, 2026
- Citation
- Landberg v City of New York, 2026 NY Slip Op 03935 (2d Dep't June 23, 2026)
- Decided
- June 23, 2026
Summary
In a sidewalk trip-and-fall appeal, the plaintiff's brief, written by Michael Sanders of Law Offices of Michael S. Lamonsoff, PLLC, cited or quoted three fictitious cases: a nonexistent Court of Appeals decision "Xiang Fu Ji v City of New York (13 NY3d 791)" for the proposition that Administrative Code section 7-210 should be "construed liberally," the opposite of what the Court of Appeals has said; a fictitious "Hausser v Giunta (88 AD3d 969)"; and a fictitious "Lack v Lack (841 NYS2d 403)." It also misstated the holdings of two real cases. Neither respondent flagged the problems. At oral argument on May 20, 2026, Sanders said the authorities came from Lexis, Westlaw, a book, or a previous case. In a later affirmation he acknowledged using AI-assisted research tools ("one of the free ones available to the public") and wrote that he "should have stated that they were hallucinated by artificial intelligence" but "was afraid to even use the words 'AI.'"
- AI tool:
- Unnamed free, publicly available AI-assisted research tool (counsel's affirmation: "one of the free ones available to the public")
- Sanction amount:
- $8,000 against attorney Michael Sanders and $2,500 against Law Offices of Michael S. Lamonsoff, PLLC, each payable to the Lawyers' Fund for Client Protection within 20 days of service
What sanction did the court impose?
On the court's own motion under 22 NYCRR 130-1.1, the Second Department (Lasalle, P.J.) directed Sanders to pay $8,000 and the law firm to pay $2,500 to the Lawyers' Fund for Client Protection within 20 days of service, with proof of payment within 10 days after. The court declined to award costs and noted that whether disciplinary action is warranted "may be a matter for the Attorney Grievance Committee"; it made no referral. The underlying appeal had been decided separately on June 3, 2026, affirming summary judgment for the defendants.
Why does Landberg v. City of New York matter for law firms using AI?
Landberg is a Second Department opinion that uses a routine sidewalk appeal to set a marker on AI-generated briefs. The court framed the problem in its first sentence: a brief “prepared with the assistance of generative artificial intelligence (hereinafter GenAI), containing citations to nonexistent cases, fictitious purported Court of Appeals quotations wholly contrary to actual law, and misrepresentations about what certain real cases actually held or decided.” The most serious fabrication inverted the governing rule. The brief quoted a nonexistent Court of Appeals decision for the proposition that Administrative Code section 7-210 is remedial and should be construed liberally, when the Court of Appeals has stated that it “must be strictly construed.”
Candor weighed heavily in the individual sanction, which the court set “[u]nder all of the circumstances presented, including Sanders’s lack of candor” and the fabricated quotations and misstatements in the brief. At argument, after declining a 15-minute recess to discern where he had found the cases, Sanders attributed the citations to Lexis, Westlaw, a book, or prior briefs. Only in a later affirmation did he acknowledge AI-assisted research, and even then “it appears that Sanders was still not completely candid”; the court added that “it appears that GenAI was used to do more than simply conduct supplemental research.” As for the firm, the court credited its general counsel’s statements that Sanders acted contrary to firm policy and that the firm had no reason to believe he was misusing GenAI, but sanctioned the firm anyway, “as the law firm’s name appeared on a brief that contained significant misrepresentations, and in light of the deterrent purpose of sanctions.”
For New York practitioners, the order sits alongside other 2026 Appellate Division decisions the court cited, including the Third Department’s Deutsche Bank v. LeTennier. Firms documenting compliance may wish to consider that the Second Department treats the firm, and not only the drafting lawyer, as answerable for a brief filed under its name.
Implications for your firm
Operational steps a firm reading this case may wish to consider documenting. Strategic and rule-application calls belong to your firm's attorneys.
- Document the firm's AI policy and its enforcement. The court credited the firm's general counsel that Sanders acted contrary to firm policy and that the firm had no reason to believe he was using GenAI beyond 'the scope of technology approved for use by the law firm,' and still fined the firm $2,500 because its name appeared on the brief.
- Train attorneys to disclose AI involvement when a court asks. The court described Sanders' decision not to be honest at oral argument as demonstrating 'professional immaturity, arrogance, and profound lack of respect for the judicial system.'
- Review opposing briefs for fabricated authority. The court noted that respondents' counsel, as officers of the court, did not alert it to the fabrications.