Two Brazilian lawyers fined $16,000 for hiding prompt injection in court documents to manipulate AI.

A Brazilian labor court fined two lawyers approximately $16,000 for embedding prompt injection instructions in white-on-white text within their legal briefs. These instructions directed the AI to perform only a superficial review of the brief without questioning its content. Although the injection did not take effect, the court ruled the behavior undermined judicial dignity and imposed a fine equal to 10% of the compensation amount involved, while notifying the bar association. The judgment was shared on X by Professor Vladimir Aras from the University of Brasília. Previously, there were similar incidents locally, such as when hidden prompts were used to require the submission of physical documents offline.