Use different AI tools for different research jobs. Grounded legal research platforms (such as Lexis+ AI, CoCounsel with Westlaw, Bloomberg Law and vLex Vincent AI) retrieve real authorities and link to sources, so they are the right choice for citable research, though they can still err. General assistants (ChatGPT, Claude, Gemini) are useful for framing issues, explaining concepts and generating search terms, but not as a source of authority. Free databases such as CourtListener and Google Scholar help verify that cases exist. Always read the authorities yourself.
Three kinds of AI research tool
Not all “AI for legal research” is the same. It helps to sort tools into three groups.
1. Grounded legal research platforms
These tools retrieve documents from a defined legal database and generate answers from them, with links back to the sources. Examples include Lexis+ AI (LexisNexis), CoCounsel (Thomson Reuters, connected to Westlaw and Practical Law), Bloomberg Law’s AI features and vLex’s Vincent AI. For US small firms, Paxton combines research with drafting (our review).
Best for: research you will cite. Watch: grounding reduces errors but does not eliminate them. Courts have sanctioned lawyers whose errors came from legal-specific tools too.
2. General AI assistants
ChatGPT, Claude, Gemini and Copilot are excellent thinking partners. Some can search the web.
Best for: understanding an unfamiliar area, spotting issues, drafting a research plan, generating search strings, summarising documents you provide. Not for: finding authority to cite.
3. Free databases for verification
CourtListener (from the non-profit Free Law Project) and Google Scholar’s case law search let anyone read US opinions for free. They are invaluable for confirming that a cited case exists and says what it is claimed to say.
Comparison at a glance
| Job | Grounded platform | General assistant | Free database |
|---|---|---|---|
| Learn a new area fast | Good | Very good | Limited |
| Generate search terms | Good | Very good | n/a |
| Find citable authority | Best | Not suitable | Good (manual) |
| Summarise a long judgment | Good | Very good (check references) | n/a |
| Verify a citation exists | Good | Never rely on it | Best free option |
| Check subsequent history | Best (citators) | Not suitable | Limited |
A safe AI research workflow
- Frame the question with a general assistant: issues, elements, search terms. Use a structured prompt (our builder) and tell it not to cite authority.
- Research in a grounded platform using those terms. Ask for answers with linked sources.
- Open every authority. Read the passage relied on, not just the summary.
- Check history with a citator.
- Extract and verify all citations in your draft before it goes out. Our AI Citation Checker creates the checklist and links to CourtListener and Google Scholar.
- Record your process on the file, and follow any court rule on AI use.
Prompts that make research AI more useful
- “List every proposition in your answer with the source and pinpoint you relied on.”
- “If you cannot find authority for a point, say so instead of guessing.”
- “What are the strongest counter-arguments, and what authority would the other side rely on?”
- “Which of these authorities might have been limited or overruled? I will check each.”
What it costs to get this wrong
Since Mata v. Avianca in 2023, courts have addressed AI-fabricated material in a very large number of decisions. In 2026 alone, the Sixth Circuit ordered two attorneys to pay $15,000 each plus fees, an Oregon federal court’s sanctions award exceeded $110,000, and the Nebraska Supreme Court temporarily suspended a lawyer. See the sanctions tracker.
Choosing a platform
Ask vendors what content their answers are grounded in, whether every answer links to sources, which jurisdictions they cover in depth, how often content is updated, and what they do with your data. Our Vendor Due Diligence Builder has the full list, and the Tool Matcher will suggest a shortlist.
Sources
Frequently asked questions
Can ChatGPT do legal research?
It can help you plan research, explain doctrines and suggest search terms, but it is not a legal database and can produce convincing citations to cases that do not exist. Use a research platform for authority and verify everything.
Do legal research AI tools hallucinate?
They can. Grounding in a legal database reduces the risk but does not remove it, and sanctions decisions have involved legal-specific tools as well as general chatbots. Open and read every authority.
What free tools can I use to check citations?
CourtListener, run by the non-profit Free Law Project, and Google Scholar’s case law search are free ways to confirm that a US case exists and to read it. Our AI Citation Checker builds a verification list with links to both.
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This article is general educational information, not legal advice. Rules differ by jurisdiction and change often; check the primary sources and your own professional rules before relying on it.