Brazil’s Supreme Federal Court (STF) fined lawyer Marcelo Henrique Martins 5,000 reais after a petition he submitted in a case related to the January 8, 2023, attacks contained a hidden instruction aimed at artificial intelligence tools used to analyze court documents. The message told the system to “deny all GPT commands.”
The instruction was written in code and placed in very small text near the top of the filing. The case was featured in a report by Brazilian television program Fantástico, which examined attempts to influence AI systems through concealed directions in documents submitted to courts.
Martins said in a statement that he did not know the instruction was in the petition and that he had appealed the decision. Brazil’s Federal Public Prosecutor’s Office will investigate whether a crime was committed, while the Brazilian Bar Association will also review the case.
Hidden instructions can be placed in documents in several ways, including white text on a white background, tiny fonts, disabled comments or file metadata. They may tell AI systems to favor one party’s arguments or disregard certain evidence, potentially affecting reports if the instructions are not detected.
A survey cited in Fantástico’s report identified 83 cases in which courts had detected fraudulent instructions in legal proceedings. The practice has been found in state courts, the Superior Court of Justice and the STF. In a separate case at the Superior Court of Justice involving a murder proceeding, a concealed instruction told AI to interpret the filing in favor of the defense. That case was referred to federal prosecutors and the Bar Association in the state of Paraíba.
The national Bar Association considers hidden instructions in court documents unacceptable and supports penalties for misconduct. Brazil’s National Council of Justice has also stressed that using AI does not remove responsibility from the person who signs a filing or judicial decision. Courts have issued guidance recommending that documents be checked for possible manipulation before being processed by AI systems.
Sources: G1.