If you’re planning to start a court case or think you may need to look up court cases, you should be aware of what can occur if you use Artificial Intelligence (“AI”) to do so.
What is AI?
AI, or artificial intelligence, has been ramping up in usage since the start of this decade and is a tool to automate human tasks by typing or speaking requests to a language trained-bot.[1]
AI platforms like ChatGPT, Claude, and Gemini have gained and continue to grow in popularity for good reason—you can automate a variety of tasks, like writing, editing photos, creating schedules and lists, and more. Just a few short years ago, Internet users could clearly tell the difference between AI-generated photos and videos. Sometimes, that’s still the case, but increasingly, AI-generated content is indistinguishable from the real thing.
However, there’s a strong tell when you use AI for writing-based tasks, and especially for court documents: that phenomenon is called case hallucinations.
What is a case hallucination?
A case hallucination is a case citation that appears in AI generative text; however, if you look that case up, it doesn’t exist.[2]
Case Hallucinations Revealed in a California Court
In March 2026, California’s First District Appellate Court published an opinion[3] holding a self-represented party accountable for submitting false case citations and fabricated quotes in his briefs to the court, which he generated using AI. In this case, the court opined that the party’s failure to verify citations was a “[] warning to litigants…to be at all times truthful and to be responsible in crafting any written arguments […].”
The Court specifically admonished that party for his inclusion of case hallucinations as a violation of the California Rules of Court, which must be followed by both lawyers and self-represented parties. Lawyers and self-represented litigants alike have been admonished for using AI in motions, pleadings, and other documents presented to the court nationwide.[4]
How should I verify if a case is a hallucination?
Even without a legal research engine, many cases are top search results if you search for them on Google or type their citation into a search bar. In some cases, you’ll also see search results for published court opinions for a specific case.
You can also visit the public law library in Martinez,[5] which has nine public computers with guides on how to access and use legal research engines to conduct the research yourself.
How can I use AI to help me in a court case?
It’s best practice to use AI as a brainstorming tool. If you’re thinking about using AI to assist you for a court case, always double and triple check any information it provides you, including case citations, quotes from cases, or any other information you may want to use.
What if I plan to use AI to write documents for the court?
If you can write your documents without using AI, that’s the safest route. However, AI shouldn’t be totally discounted. As above, it’s a great tool for brainstorming and getting yourself started. If you are dealing with any case citations, be sure to verify them before including them in anything you file with the court.
If you have legal questions, Contra Costa Senior Legal Services is an even better avenue than it! If you’ve used it to look up any cases for your legal issue, we can help you check that they’re real and understand the law, too. Call us at (925) 609-7900 for assistance.
[1] See, e.g., What Is Artificial Intelligence (AI)? | IBM
[2] See, e.g., AI on Trial: Legal Models Hallucinate in 1 out of 6 (or More) Benchmarking Queries | Stanford HAI
[3] Sheerer Opinion (Using Generative AI for Case Citations).pdf
[4] See, e.g., Another ‘hallucinated’ court filing highlights the difference between Silicon Valley and the rest of the world | CNN Business
[5] 1026 Escobar Street, Suite 2C, Martinez, CA, 94553. There is another law library located in Contra Costa County at: Room 237, George D. Carroll Courthouse, 100 South 37th Street, Richmond, CA 94804.