The failure mode is specific and repeatable. A lawyer asks an AI tool to draft or bolster an argument, the tool produces citations that are formatted flawlessly, and because the format is right the citations survive a human skim. The problem is that correct format is exactly what a language model is good at reproducing — whether or not the underlying case is real. Peer-reviewed research has found that even leading AI legal-research tools still return incorrect answers on a meaningful share of queries, so the model alone cannot be the safeguard.
Why does AI fabricate citations that look real?
A language model generates text that is statistically plausible, not text that is verified against a database of what exists. Bluebook citation format is highly regular, so a model reproduces it almost perfectly — the reporter, the volume, the pincite, a confident parenthetical. What it cannot do on its own is guarantee the opinion behind that citation was ever written. That is why perfect formatting must never be treated as evidence a case is real; it is the trait that makes fabricated citations dangerous.
What do the rules now require?
The professional expectation has hardened from norm into written obligation. Federal Rule of Civil Procedure 11 already requires that legal contentions be warranted and that filings not be presented for an improper purpose, and individual judges have issued standing orders requiring lawyers to certify that AI-assisted authorities are real and human-verified. Advisory-committee proposals would extend a version of that duty more broadly. The through-line is consistent: a filer is expected to be able to show that cited authorities exist and were checked.
How do you catch a fabricated case before filing?
- Resolve existenceMatch every citation against live case-law by its exact reporter citation — not the case name, which a model can invent convincingly.
- Check the quotationCompare quoted passages against the published opinion, catching misquotes and invented quotations.
- Confirm good lawOverlay good-law standing from your firm’s citator, so an overruled case is flagged even when it is real.
- Certify, do not just flagProduce a signed, sealed certificate of what was checked, so the verification is evidence rather than an assertion.
