Why AI Invents Statutes and Judgments

Non-existent case numbers in court filings have already cost several lawyers a fine and their reputation. This isn't the model being malicious, it's simply how language models work. Anyone who understands this knows why a simple "be accurate" instruction isn't enough, and why AI needs a genuine source.
Why AI Invents Case Law and How to Prevent It
Europaius Malta: Corpus Contents

The examples in this guide are based on Czech law. The same tools also work with the Europaius Malta corpus:

4 883
Laws
553
Laws with AI explanation

Europaius Malta → · Search

How a Hallucination Arises

A language model isn't trained on facts but on likely continuations of text. When you write "according to the judgment of the Supreme Court, case no.", the model fills in something that looks like a case number, because it has seen thousands of such patterns. It has no way to verify that the decision actually exists. The same applies to section numbers, deadlines and the wording of provisions.

The less data on a topic the model has seen, the more confidently it makes things up. Czech legislation and case law are weakly represented in training data, so the risk is greatest precisely there. An answer in English or German may be more accurate than one in Czech, which is, paradoxically, the worst possible combination for Czech lawyers.

What Happened When Lawyers Relied on It

The first known case dates back to 2023 in New York, where lawyers submitted a filing to the court containing six non-existent decisions generated by ChatGPT and were fined. Since then, similar cases have been multiplying in the United States, Canada, the United Kingdom and Europe, and courts are beginning to require declarations on the use of AI. In the Czech environment, the first filings citing sources that cannot be traced are starting to appear.

Why Telling the Model "Don't Make Things Up" Isn't Enough

An instruction in the prompt reduces the model's willingness to fabricate citations, but gives it nothing to replace them with. The model either refuses to answer, answers vaguely, or still makes things up anyway. The only reliable solution is to give it a source it can actually read from: this principle is called grounding.

Grounding works by having the model call a search in a real database before answering, retrieve the text, and answer based on it. The citations are then not generated but copied from the result, including a link you can open yourself.

How the Europaius Connector Solves This

A Workflow That Practically Eliminates Hallucinations

Ask with an explicit request for a source. Have the AI search first, then summarise. Open every citation you use in a document via its link. For key statements, ask again with a differently worded query to check whether the same result comes up. And keep track of what the AI has searched for; the Europaius connector logs every query under your account, so you can always return to the research.

Connect Europaius to Your AI
The connector address is the same for all tools. Sign in with your email, done in under two minutes.
https://mcp.europaius.com/mcp
Connection Guide → · Pricing

Frequently Asked Questions

Does the connector mean AI will never make a mistake again?

No. The citations will be genuine, but the AI may select an irrelevant decision or summarise its conclusion incorrectly. The links exist so that you can check it.

Does Claude make things up too, or just ChatGPT?

All language models do, without exception. Only the degree differs. The solution is the same for all of them: give them a verified source.

How do I know the AI actually used the connector?

Both Claude and ChatGPT display in the response which tools they called and with what query. If no call is shown, the answer came from memory.

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All Guides: Laws & Case Law in Claude: Connect via MCP Connector · Microsoft Copilot and Legal Sources: Europaius MCP Connector · Perplexity with the Europaius legal corpus: custom MCP connector · Legal corpus in Claude Code, Cursor and VS Code via MCP · AI in a Law Firm: Deployment with Verified Sources · AI for In-House Lawyers: Contracts, Compliance, Fast Answers · AI for Accountants and Tax Advisors: Laws and Case Law · Comparing Law Across EU Countries with AI: One Query, 25 Countries · Employment Law with AI: Dismissals & Severance Pay · Tenancy Law and AI: Notice, Deposit, Rent Increases by Law · GDPR and AI Compliance: Regulation, Statute and Case Law Combined · Europaius MCP Connector Security: OAuth, Data, Tokens · Custom AI Agent with a Legal Corpus: MCP SDK and API Key · Statutory Interpretations in AI: Clear, No Hallucinations · Pricing and Limits of the Europaius MCP Connector

General information only; does not replace legal advice. Connecting the connector requires a Europaius account (free of charge). More About Europaius · Europaius MT