What was hallucinated

Fabricated: Case Law | Plaintiff's opposition cited a non-existent SDNY case to argue charter schools are not subject to notice-of-claim requirements; the Court noted the case does not exist. || Fabricated: Case Law | Plaintiff's opposition cited a non-existent EDNY case for the same notice-of-claim argument; the Court confirmed it does not exist. || Fabricated: Case Law | Plaintiff's opposition cited a non-existent New York Supreme Court slip opinion regarding a charter school; the Court stated the case does not exist.

Details

"The appearance of hallucinated citations in briefs generated from AI is no longer in its nascent stage. Regrettably, the number and regularity with which courts have been faced with hallucinations in court filings continues to rise both in this country and abroad. See Damien Charlotin, AI Hallucination Cases, (Aug. 6, 2025)https://www.damiencharlotin.com/hallucinations/ (database tracking legal decisions “in caseswhere generative AI produced hallucinated content,” evidencing 255 cases to date) (hereinafter “Charlotin Database”).[...]By far, the majority of courts impose sanctions upon the offending lawyer for this sort of conduct and warnings or reprimands have been meted out in cases typically involving pro se litigants. See Charlotin Database, supra. However, there are circumstances where, in the Court’s discretion, monetary sanctions have not been imposed notwithstanding the violation of Rule 11."

Sanction teardown · E.D. New York, USA · 2025-08-07

Hall v. The Academy Charter School

What happened

In E.D. New York, USA, a filing relied on an unnamed/unconfirmed AI tool to help draft legal argument. The court identified the following problems with the citations in that filing:

Fabricated (Case Law)

Plaintiff's opposition cited a non-existent SDNY case to argue charter schools are not subject to notice-of-claim requirements; the Court noted the case does not exist.
Fabricated (Case Law)

Plaintiff's opposition cited a non-existent EDNY case for the same notice-of-claim argument; the Court confirmed it does not exist.
Fabricated (Case Law)

Plaintiff's opposition cited a non-existent New York Supreme Court slip opinion regarding a charter school; the Court stated the case does not exist.

Which AI tool

an unnamed/unconfirmed AI tool. Note: Charlotin's public database records tool attribution only where a court order, brief, or reporting on the matter states it explicitly; "unidentified" or "implied" means the record indicates AI use but does not name a specific product — we do not guess.

Outcome

No monetary sanctions imposed; counsel admonished

Additional detail

"The appearance of hallucinated citations in briefs generated from AI is no longer in its nascent stage. Regrettably, the number and regularity with which courts have been faced with hallucinations in court filings continues to rise both in this country and abroad. See Damien Charlotin, AI Hallucination Cases, (Aug. 6, 2025)https://www.damiencharlotin.com/hallucinations/ (database tracking legal decisions “in caseswhere generative AI produced hallucinated content,” evidencing 255 cases to date) (hereinafter “Charlotin Database”).[...]By far, the majority of courts impose sanctions upon the offending lawyer for this sort of conduct and warnings or reprimands have been meted out in cases typically involving pro se litigants. See Charlotin Database, supra. However, there are circumstances where, in the Court’s discretion, monetary sanctions have not been imposed notwithstanding the violation of Rule 11."

How Citation Safe would have caught this

Citation Safe runs three deterministic layers before a brief is filed: (1) does the citation exist against CourtListener's database of published opinions, (2) if quoted, does that exact language appear in the source, (3) does the cited case actually support the proposition it is cited for. Fabricated case citations fail Layer 1. Fabricated or misattributed quotations fail Layer 2 even when the underlying case is real. Misrepresented holdings — a real case cited for a proposition it does not support — are the target of Layer 3. None of these checks involve asking another language model whether the citation looks right; they are lookups and text-matches against the actual source, which is why a hallucinated citation has to survive a direct lookup against the authoritative source — not another model's opinion — to earn a VERIFIED stamp; our measured false-verify rate is published live at /quality.

Check a brief before you file it → · See our live false-verify rate

Source: https://www.damiencharlotin.com/documents/652/Hall_v._the_Academy_Charter_School_USA_7_August_2025.pdf, via Damien Charlotin's public AI Hallucination Cases Database (CC0).