Brazilian court fines lawyer for hidden AI prompt injection

A cosmetics company in Santa Catarina was convicted of bad‑faith litigation after inserting hidden “prompt injection” commands into a petition to manipulate an artificial‑intelligence tool used by the court. The judge imposed the maximum 10 % penalty on the case value, ordered the removal of the plaintiff’s name from credit‑blacklist registers and fined the company R$ 5,000 in moral damages. The decision was referred to the Brazilian Bar Association for possible ethical disciplinary action.

In a separate case in Paraíba, a judge imposed two fines totalling R$ 32,800 on a lawyer who concealed AI commands in a seven‑page petition, directing the system to ignore impartiality and grant the request. The court characterised the act as “prompt injection,” a fraudulent technique that threatens the integrity of judicial decisions. The lawyer was also reported to the local Bar Association and the Public Prosecutor’s Office, and the petition was restricted to judges and court staff.

Both rulings highlight growing judicial concern over the misuse of generative AI in legal proceedings and reference recent technical notes issued by Brazil’s judicial AI governance bodies warning of hidden‑command risks.