What was hallucinated

Fabricated: Case Law | Mis-citation/misrepresentation of Page v. Parsons: GBI cited a federal reporter that does not correspond to that Oregon appellate decision and relied on it for a proposition the real Oregon decision does not support. || Fabricated: Case Law | Entirely fabricated opinion and citation attributed to 'Stell v. Cardenas' (case and reporter do not exist; real Case No. 3:21-cv-413 is a different matter). Court found no such opinion at the cited Westlaw number or parties.

Details

Lawyer later explained that he had "used Microsoft’s Copilot for its editing functions in an effort to review and improve the draft document by fixing grammar, spelling, and improving badly phrased sentences" - not for legal research.On November 12, 2025, the court resolved the Show Cause proceedings without formal sanctions.

Sanction teardown · D. Oregon, USA · 2025-10-27

Green Building Initiative, Inc. v. Stephen R. Peacock & Green Globe Limited

What happened

In D. Oregon, USA, a filing relied on Copilot to help draft legal argument. The court identified the following problems with the citations in that filing:

Fabricated (Case Law)

Mis-citation/misrepresentation of Page v. Parsons: GBI cited a federal reporter that does not correspond to that Oregon appellate decision and relied on it for a proposition the real Oregon decision does not support.
Fabricated (Case Law)

Entirely fabricated opinion and citation attributed to 'Stell v. Cardenas' (case and reporter do not exist; real Case No. 3:21-cv-413 is a different matter). Court found no such opinion at the cited Westlaw number or parties.

Which AI tool

Copilot. 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

Show Cause Order

Additional detail

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://reason.com/volokh/2025/10/29/apparent-ai-hallucinations-in-filing-from-two-500-lawyer-firms/, via Damien Charlotin's public AI Hallucination Cases Database (CC0).

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