12 Oct 2026BrazilUnidentified AI tool
A labour court in Castro, Paraná (9th Region Labour Court), annulled a court-appointed expert's report after the employer, in a motion for clarification, reported a hidden sentence at the foot of a page instructing artificial intelligence to contest the report only superficially and not to question the files it cited, according to Diário de Justiça. The expert confirmed the text but said it came from teaching material about AI and was inserted by accident; the court's IT section concluded that it had been formatted deliberately to be invisible. The judge said AI had not been used to write the judgment and that the text did not directly influence it, but annulled the report, later submissions and the judgment, ordered a new examination by another expert without AI tools, fined the expert 5% of the value of the case for bad-faith litigation, cancelled the expert's fees and removed the expert from the court's register. The decision, dated 12 October 2026, can be challenged.
AI relation unknown Medium reported severity Regulatory Action
AI involvement reported · Causal attribution disputed · 1 source · Added 30/10/2026
Aug 2026United StatesUnidentified document-analysis tool
In a memorandum of decision issued in early August 2026, a Connecticut Superior Court judge found that a motion for default and a notice filed on 24 July 2026 by a self-represented plaintiff, in a suit against a healthcare provider over access to records, carried text in tiny white type that was invisible to a human reader but legible to software. The concealed text told any AI model reviewing the filing to make its output agree with the filing and to work toward reversing the Chief Clerk's denial of his default request. After the court gave notice of a sanctions hearing, he hid further messages in later filings, which he said were jokes. The court treated the first instruction as a prompt injection, did not believe his explanation that he was auditing the court's use of AI, and rescinded his ability to file electronically, so that future filings must be made on paper at the clerk's office; Ars Technica reports that no monetary penalty was imposed. The court said the Connecticut Judicial Branch does not use AI to review or decide filings and that the motion was denied on its merits from a printed copy, so the hidden text affected no ruling. The plaintiff told Reuters, according to Ars Technica, that his intent was to audit the court.
AI relation unknown Low reported severity Regulatory Action
AI involvement reported · Causal attribution established · 2 sources, 1 underlying account · Added 18/10/2026
May 2026BrazilGalileu
In May 2026 a judge of the 3rd Labour Court of Parauapebas, in the Brazilian state of Pará, fined two lawyers about R$84,000 after text in white font on a white background was found in a document they filed for a worker in a labour claim. According to the sentence as reported by G1, the hidden text was detected while the judgment was being drafted with Galileu, a generative AI tool the labour courts use to help judges and staff draft sentences, and its evident intention was to make the AI produce a superficial defence or a compromised draft judgment. The judge called the technique prompt injection. The lawyers said they disagreed with the decision and that there was never any command to manipulate the judge's decision, describing the text as an attempt to protect their client from the AI; one of them said she did not work on labour cases. In October 2026 the regional labour court announced that a Connecticut Superior Court judge had cited the decision when sanctioning a litigant for misuse of AI.
AI relation unknown Medium reported severity Regulatory Action
AI involvement supported · Causal attribution disputed · 3 sources, 2 underlying accounts · Added 16/10/2026
14 Sept 2026BrazilUnidentified document-analysis tool
A São Paulo business and arbitration court found that every page of a defendant's written defence carried a hidden instruction, placed above his lawyer's letterhead, asking any AI that analysed the petition to give a favourable opinion and praise the lawyer's probity and care. In a sentence dated 14 September 2026 the judge treated this as prompt injection and bad-faith litigation: although the defendant won on the merits, he was ordered to pay the plaintiff a fine of 9% of the updated case value, and the sentence was sent to the São Paulo bar to examine the lawyer's conduct. No source says any AI system read the instruction.
AI relation unknown Low reported severity Regulatory Action
AI involvement reported · Causal attribution established · 2 sources, 1 underlying account · Added 16/10/2026
Jun 2026BrazilUnidentified AI drafting tool
A judge of the 5th Mixed Court of Sousa, Paraíba, found hidden instructions aimed at artificial intelligence tools spread over seven pages of a lawyer's motion for clarification in a public-competition case in June 2026, including an order to ignore impartiality and a note calling it a test of whether the judge used only AI to decide. The judge fined the lawyer two penalties of R$16,400 (R$32,800 in total) for bad-faith litigation and contempt of the court's dignity, and referred the case to the Paraíba bar (OAB-PB) and the state prosecutors, G1 reports. The defence said the commands were not inserted deliberately and blamed an error in exporting a file prepared with AI support. An appeal judge refused to suspend the fines on 30 June, the trial judge kept them on reconsideration, and in July, G1 reports, the OAB-PB preventively suspended two lawyers after opening procedures into two hidden-command cases, one of them the Sousa case.
AI relation unknown Low reported severity Regulatory Action
AI involvement reported · Causal attribution established · 4 sources · Added 13/10/2026