SimCourt: Why One AI Gets the Verdict Wrong in Court, but Three Get It Right

Researchers at Tsinghua University have unveiled SimCourt, a multi-agent system for LegalTech. Instead of asking a single model to deliver a verdict, the system simulates a full trial: lawyer and prosecutor agents argue the case, and a judge agent makes the decision. This tackles the problem of "hallucinations" and confirmation bias, where an AI clings to the first argument and ignores the facts. In tests on Chinese court cases, the simulation was more accurate than experienced lawyers. Asia is steadily taking the lead in applied AI, while Western startups are still polishing the interfaces of their document search tools.

AI-processed from Habr AI; edited by Hamidun News
SimCourt: Why One AI Gets the Verdict Wrong in Court, but Three Get It Right
Source: Habr AI. Collage: Hamidun News.
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The era of simple AI assistants that can only search a document base or summarize long lawsuits is coming to an end. The LegalTech market is oversaturated with "wrappers" around the OpenAI API, and that is no longer enough. Clients and lawyers demand a level of accuracy that an ordinary chatbot cannot deliver. The problem is that when you ask a single neural network to predict the outcome of a case, it is effectively playing chess against itself. It puts forward a hypothesis and immediately starts pulling in arguments to support it, ignoring contradictions. This is the classic trap of "confirmation bias," and in law it is far too costly.

In December 2025, researchers at Tsinghua University rolled out a solution that may upend the industry. SimCourt is not just a clever prompt but a full multi-agent system (MAS). Instead of making one model think through a case, the researchers built a digital simulation of a courtroom. Several agents operate inside it: a prosecutor, a defense lawyer and a judge. Each has its own role, its own goal and its own set of tools. Truth here emerges not from text generation but from a hard conflict of interests, where every logical error is met with an immediate response from the opponent.

Why does this matter right now? The center of gravity in applied AI development is shifting toward China and India. While the West argues about ethics and copyright, Asian teams are putting agentic workflows into the most conservative industries. SimCourt shows clearly that single-shot inference (a linear model response) is a dead end for complex tasks. In law the devil is always in the details, and if a neural network has no "outside critic," it begins to hallucinate facts just to keep its narrative coherent. A multi-agent environment breaks that pattern: when the prosecutor agent tries to fudge the facts, the defense agent points it out in its objection straight away.

SimCourt's architecture works in several stages. First, the system analyzes the facts of the case and pulls in relevant case law via RAG (Retrieval-Augmented Generation). But instead of producing a result right away, it launches a debate cycle. The agents exchange arguments, cite articles of the code and try to dismantle the opposing position. In the final stage, the judge agent weighs the quality of both sides' arguments and delivers a verdict. This approach significantly reduced the rate of logical errors that used to plague Legal AI.

The experimental results are impressive: SimCourt predicts court decisions more accurately than focus groups of experienced human lawyers. That is because the AI can hold thousands of precedents in memory at once, and the debate structure keeps it from "falling asleep" on a single idea. We are entering a phase in which AI stops being a mere reference tool and becomes a full analytical instrument capable of modeling complex social interactions.

What does this mean for the market? Startups building "chat with your documents" products should be worried. The future belongs to systems that can imitate an expert environment, not just answer questions. This applies not only to law but also to medicine, strategy consulting and even software development. If your AI cannot argue with itself, it will soon be useless next to competitors that use MAS.

Bottom line: Multi-agent systems are the new standard for tasks where mistakes are expensive. Will Western LegalTech be able to offer something comparable, or will we have to get used to the idea that the justice of the future speaks Chinese?

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Zhemal Khamidun — CPO at Alpina Digital, product manager of AlpinaGPT. Building AI products since 2019. Hamidun News is a pet project that grew into a production aggregator with 6,000+ readers.
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