Spain's Supreme Court warns on AI‑generated legal citations and updates labor casation rules

The Spanish Supreme Court’s Administrative Litigation Chamber identified, for the first time, a defense brief containing algorithmic hallucinations—citations to jurisprudence that do not exist. The case involved a small claim over late‑paid health‑service invoices and prompted the court to order the lawyer to verify each cited decision within three days, underscoring the growing risk of uncritical AI‑generated legal text.

In a separate decision, the Court’s Fourth Chamber issued a landmark ruling on the objective casational interest for labor appeals. The judgment requires lawyers to demonstrate the jurisprudential value of a case before filing a petition for cassation, shifting the process from merely resolving contradictory rulings to ensuring coherent and evolving labor law doctrine.

Both rulings signal a tighter procedural scrutiny by Spain’s highest court, aiming to guard the legal system against unreliable AI outputs and to refine the strategic use of cassation in labor disputes.