An AI cited a court case in a real legal brief. The case did not exist. A judge fined the lawyer $30,000. That sanction came from the Sixth Circuit in March 2026, and it was not a freak event. Even purpose-built legal AI invents cases: Stanford RegLab found Westlaw Precision hallucinating at 33 percent, Lexis+ at 17 percent (Journal of Empirical Legal Studies, 2025). The test a court applies is simple: does the cited case exist, and does it say what you claimed? So we built a demo, CiteGuard, a verification layer around whatever AI a firm already uses. It does not draft and it does not do research. It takes the finished brief and checks every citation against real case law on CourtListener. When a cite is fabricated, CiteGuard proves it with a live lookup that returns zero results, then holds the filing. Not a hunch that a case looks fake. A deterministic check where a fabricated citation can never pass the gate. One built-in sample brief cites "Halstead v. Ferngate Holdings, 823 U.S. 1199." U.S. Reports has no volume 823. The cite is impossible, and the check catches it every run. (The samples are labeled synthetic excerpts, so a fabrication gets caught with no real matter on the line.) Honest question if your firm files AI-drafted work: after the model writes the brief, does anything confirm each cited case is real before it reaches a judge, or does it go out on the model's word? #LegalTech #LegalAI #AIGovernance #LegalOps