How AI legal research tools work, and how to choose one

AI has changed legal research faster than almost any other part of legal work. Here's how these tools actually work, and what separates a genuinely useful one from a risky one.

Andrew Mellett
Andrew Mellett

July 07, 2026

Female and male reviewing how AI legal research tools work

What are AI legal research tools?

AI legal research tools use natural language processing and large language models to search, interpret, and summarise case law, legislation, and secondary legal sources, going beyond keyword search to understand the substance of a legal question. They are one category within the broader legal AI tools landscape.

How is AI legal research different from traditional legal databases?

Traditional legal databases rely on keyword and boolean search, which requires the researcher to already know the right terms to search for. AI legal research tools can interpret a question asked in plain language, retrieve relevant authority, and summarise how it applies, which significantly reduces the time spent on the early stages of research.

What can AI legal research tools actually do?

Answer a legal question in plain language and surface the supporting authority

Summarise a case or piece of legislation into its key holdings

Identify related or conflicting authority across a jurisdiction

Track changes in relevant law or regulation over time

Are AI legal research tools accurate and reliable?

Accuracy varies significantly between tools, and this is the single most important thing to test before adopting one. The risk with any language model based research tool is generating a plausible-sounding but incorrect citation, so the strongest tools show their sources transparently and let you verify every claim against the original authority rather than asking you to trust the summary.

What should you look for in an AI legal research tool?

Source transparency is the top priority: you should be able to see exactly which case or provision supports every claim the tool makes. After that, check coverage of your relevant jurisdictions, and how well the tool integrates with your drafting workflow, since research that stays siloed from drafting creates an extra manual step.

Does Plexus offer AI legal research capability?

Plexus's AI layer, Plexus Counsel, is focused on applying your organisation's own precedents and policies within contract and matter workflows, rather than acting as a general case law research tool. For teams that need both, Plexus is commonly used alongside a dedicated legal research platform.

Andrew Mellett

Andrew Mellett

Andrew Mellett is the Founder and CEO of Plexus, a global leader in AI-powered legal technology. Recognised by the Financial Times and Harvard Business Review for his pioneering work in legal innovation, Andrew leads Plexus’s mission to train digital lawyers, helping the world’s top companies streamline legal operations and scale expertise with artificial intelligence.

All your legal work in one AI-powered platform

Faster reviews, self-service for business teams, and smarter compliance in every workflow.

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