New AI Fact-Checker Catches Made-Up Law Citations
AI legal tools invent court cases — this one double-checks every claim.
Researchers built GANDR (Grounded ANswer DRafter), a two-agent system in which a Drafter writes an answer in a structured legal-reasoning format and a separate Critic, with the same view as a human verifier, audits each claim against its cited source and emits a per-claim audit trace on every round. Paired with a strict correctness criterion requiring every citation to resolve to a passage the retriever returned, GANDR topped a 185-item legal benchmark where all six systems shared one backbone, one retrieval surface, and one citation instruction — ranking first on every primary metric, reaching 70.8% strict accuracy, and leading the strongest baseline by 11.3 points (p<0.01). Against two law-trained annotators, the audit flagged under-supported claims at F1 0.84 as a binary detector, while its four-way verdict labels agreed only weakly and are advisory.
- Two AI programs split the work: one writes the legal answer, a second audits every citation against its source.
- It scored 70.8% on a 185-question legal test, beating the next-best system by 11.3 points.
- Its fake-citation warnings matched two human lawyers' judgments about 84% of the time — but detailed verdicts stay advisory.
Why It Matters
If you hire a lawyer or use AI legal tools, this makes invented case citations far easier to catch.