Mercante v. Tarzia
E.D. New York · Oct 2, 2026
What happened in this matter?
Fabricated: Case Law | Defense counsel cited a nonexistent case as authority for denying a fee motion. The court confirmed that the case was fictitious, characterized it as an AI hallucination, and held that citing it violated Rule 11. Defense counsel admitted using a Westlaw AI tool to identify cases and copying propositions without verifying the authorities or citations. The court found one fictitious case, several false quotations and mis-citations, and at least one materially misrepresented precedent. It held that citing the fictitious case violated Rule 11, but affirmed the magistrate judge's decision not to issue an order to show cause or impose sanctions because Rule 11 sanctions are discretionary, the errors caused no sufficiently demonstrated burden requiring further proceedings, and an admonition was within the court's discretion.
- Why the court cared
- The structured public record identifies fake citations and fabricated quotes and records a recorded judicial or procedural response. The linked source controls the precise reasoning and procedural context.
- Why it matters now
- This matter connects fake citations and fabricated quotes with a recorded judicial or procedural response in E.D. New York. It provides a source-linked baseline for verification, supervision, and response controls.
Why this matter is tracked
Fabricated: Case Law | Defense counsel cited a nonexistent case as authority for denying a fee motion. The court confirmed that the case was fictitious, characterized it as an AI hallucination, and held that citing it violated Rule 11. Defense counsel admitted using a Westlaw AI tool to identify cases and copying propositions without verifying the authorities or citations. The court found one fictitious case, several false quotations and mis-citations, and at least one materially misrepresented precedent. It held that citing the fictitious case violated Rule 11, but affirmed the magistrate judge's decision not to issue an order to show cause or impose sanctions because Rule 11 sanctions are discretionary, the errors caused no sufficiently demonstrated burden requiring further proceedings, and an admonition was within the court's discretion.
This matter connects fake citations and fabricated quotes with a recorded judicial or procedural response in E.D. New York. It provides a source-linked baseline for verification, supervision, and response controls.
Record details
What the record establishes about AI use
Westlaw AI is recorded in the source dataset; confirm the basis in the linked document.
Procedural posture is not separately recorded in the current dataset.
Correction behavior is not separately verified in the current record.
Tracked discrepancy record
6 citation, quotation, or authority issues are recorded in the source dataset.
- Fabricated: Case Law | Defense counsel cited a nonexistent case as authority for denying a fee motion. The court confirmed that the case was fictitious, characterized it as an AI hallucination, and held that citing it violated Rule 11.
- False Quotes: Case Law | Defense counsel attributed quoted language concerning willfulness, bad faith, and proportionality of sanctions to a real case, but the quoted language does not appear in the decision. The court found the citation correct and the case generally relevant, but treated the quotation as an apparent misuse of quotation marks rather than clear proof of AI use.
- False Quotes: Case Law | Defense counsel quoted a definition of attorney work product and attributed it to a real case, but the quoted language does not appear in that decision. The court noted that the case does address attorney work-product protection but found no clear indication that AI caused the error.
- Misrepresented: Case Law | Defense counsel cited a real case for a proposition about substantial privacy interests, but the Second Circuit's holding was the opposite: it declined to maintain a permanent seal because privacy interests were weak compared with the presumption of public access. The court treated this as a serious mischaracterization but not conclusive proof of AI use.
- Fabricated: Case Law | Defense counsel cited the correct case name but used an unrelated case's database identifier. The court determined that the real case supported the stated proposition despite the incorrect citation.
- Fabricated: Case Law | Defense counsel cited the correct case name but used an unrelated case's database identifier. The court determined that the real case supported the stated proposition despite the incorrect citation.
Questions this record answers
- What happened in Mercante v. Tarzia?
- Fabricated: Case Law | Defense counsel cited a nonexistent case as authority for denying a fee motion. The court confirmed that the case was fictitious, characterized it as an AI hallucination, and held that citing it violated Rule 11. Defense counsel admitted using a Westlaw AI tool to identify cases and copying propositions without verifying the authorities or citations. The court found one fictitious case, several false quotations and mis-citations, and at least one materially misrepresented precedent. It held that citing the fictitious case violated Rule 11, but affirmed the magistrate judge's decision not to issue an order to show cause or impose sanctions because Rule 11 sanctions are discretionary, the errors caused no sufficiently demonstrated burden requiring further proceedings, and an admonition was within the court's discretion.
- Why does Mercante v. Tarzia matter for legal AI risk?
- This matter connects fake citations and fabricated quotes with a recorded judicial or procedural response in E.D. New York. It provides a source-linked baseline for verification, supervision, and response controls.
- What does the public record establish about Mercante v. Tarzia?
- The record summarizes the outcome described in the linked public source. The recorded document is hosted in the upstream publisher archive. This page is not a substitute for the complete docket, subsequent history, or jurisdiction-specific advice.
- Which source supports this Mercante v. Tarzia summary?
- The recorded source is Damien Charlotin case archive. It is classified as publisher document archive; review the linked material and subsequent docket history before relying on this summary.
Related matters
Related by court, jurisdiction, tool, or classified failure pattern. Similarity does not imply the same facts or outcome.