What was hallucinated

Fabricated: Case Law | Citation to "Lewis v. CCPOA, 2009 WL 890585, at *4 (E.D. Cal. Mar. 31, 2009)" does not match the cited court/date/Westlaw identifier; court notes a different Lewis decision exists with a different Westlaw ID and date. || Fabricated: Case Law | Citation to "James v. Claussen, 2022 WL 1120273, at *3 (C.D. Cal. Apr. 14, 2022)" does not correspond to any such case; Westlaw identifier cited corresponds to an appellee brief in a Texas Court of Appeals. || Misrepresented: Case Law | Citation to Hernandez v. Polanco Enters., Inc., 19 F. Supp. 3d 918, 931 (N.D. Cal. 2013) is to a real decision but the order cited does not address depositions or corrections as the Opposition suggests.

Details

Penalty decided in an order from the next day.

Sanction teardown · C.D. California, USA · 2025-06-26

Twist It Up, Inc. v. Annie International, Inc.

What happened

In C.D. California, 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)

Citation to "Lewis v. CCPOA, 2009 WL 890585, at *4 (E.D. Cal. Mar. 31, 2009)" does not match the cited court/date/Westlaw identifier; court notes a different Lewis decision exists with a different Westlaw ID and date.
Fabricated (Case Law)

Citation to "James v. Claussen, 2022 WL 1120273, at *3 (C.D. Cal. Apr. 14, 2022)" does not correspond to any such case; Westlaw identifier cited corresponds to an appellee brief in a Texas Court of Appeals.
Misrepresented (Case Law)

Citation to Hernandez v. Polanco Enters., Inc., 19 F. Supp. 3d 918, 931 (N.D. Cal. 2013) is to a real decision but the order cited does not address depositions or corrections as the Opposition suggests.

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

Monetary Sanction (monetary penalty: 500 USD.)

Additional detail

Penalty decided in an order from the next day.

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/775/Twist_it_Up_v._Annie_International.pdf, via Damien Charlotin's public AI Hallucination Cases Database (CC0).

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