What was hallucinated

Fabricated: Case Law | Counsel cited this STJ Río Negro decision as supporting objective liability; court could not locate the precedent and determined it to be nonexistent. || Fabricated: Case Law | Counsel cited this STJ Río Negro decision; court was unable to find it and treated it as a non-existent AI-generated citation. || Fabricated: Case Law | Counsel cited this STJ Río Negro decision; court could not locate it and concluded it was a fabricated citation likely produced by generative AI. || Fabricated: Case Law | Counsel cited this STJ Río Negro decision; court's search found no trace of the precedent and characterized it as an AI 'hallucination'. || Fabricated: Case Law | Counsel cited a provincial/circuit civil appellate decision 'Mosca c/ Vilches' (CNCiv Sala B) as binding support; court could not locate that decision in official repositories and treated it as nonexistent. || Misrepresented: Case Law | Counsel cited CSJN Fallos 308:1109 as supporting the proposition; court found the cited CSJN decision (Honorio Juan Luján) exists but determined it was unrelated to the proposition invoked (misuse/misrepresentation of precedent).

Sanction teardown · CA Río Negro, Argentina · 2025-12-12

A.M., F.A. c/ C.N.H y otros

What happened

In CA Río Negro, Argentina, 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)

Counsel cited this STJ Río Negro decision as supporting objective liability; court could not locate the precedent and determined it to be nonexistent.
Fabricated (Case Law)

Counsel cited this STJ Río Negro decision; court was unable to find it and treated it as a non-existent AI-generated citation.
Fabricated (Case Law)

Counsel cited this STJ Río Negro decision; court could not locate it and concluded it was a fabricated citation likely produced by generative AI.
Fabricated (Case Law)

Counsel cited this STJ Río Negro decision; court's search found no trace of the precedent and characterized it as an AI 'hallucination'.
Fabricated (Case Law)

Counsel cited a provincial/circuit civil appellate decision 'Mosca c/ Vilches' (CNCiv Sala B) as binding support; court could not locate that decision in official repositories and treated it as nonexistent.
Misrepresented (Case Law)

Counsel cited CSJN Fallos 308:1109 as supporting the proposition; court found the cited CSJN decision (Honorio Juan Luján) exists but determined it was unrelated to the proposition invoked (misuse/misrepresentation of precedent).

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

Admonishment

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/1429/A.M._F.A._c._C._N.H_y_Otros_Argentina_12_December_2025.pdf, via Damien Charlotin's public AI Hallucination Cases Database (CC0).

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