Lawyers have always been accountable for their work. That was true before AI, and it is just as true now. A brief carries your name. An argument carries your judgment. A citation carries your reputation. None of that changes because an AI tool helped you produce it faster.Ìý

That’sÌýwhy when firms talk about adopting AI for legal work, the first questionÌýshouldn’tÌýbe about speed or cost savings. It should be: can IÌýactually verifyÌýwhat this produces? If youÌýcan’tÌýtrace an output back to its source, check whether that source is still good law, and inspect the reasoning that connected the two, youÌýdon’tÌýhave work product. You have a draft youÌýcan’tÌýstand behind.Ìý

That standard is not new.ÌýWhat’sÌýnew is how many lawyers are finding out the hard way that the AI tools they adoptedÌýweren’tÌýbuilt with it in mind.Ìý

Courts across the United States have now sanctioned attorneys forÌýsubmittingÌýbriefs with fabricated citations, false quotes, and mischaracterized precedent — all generated by AI and not verified by the attorneys. When those tools are built on content scraped from the web rather than authoritative legal sourcesÌýmaintainedÌýby practicing attorneys, the risk of error is structural. The AI has no way to know whether a case is still good law, whether a statute has been amended, or whether a citationÌýactually supportsÌýthe argumentÌýit’sÌýbeing used to make. Verification becomes difficult not because the toolsÌýdon’tÌýshow their work, but because the underlying sourcesÌýcan’tÌýbe trusted in the first place.Ìý

AtÌýThomsonÌýReuters,ÌýweÌýunderstandÌýthat lawyersÌýdon’tÌýjust need to find the law — they need to be able to stand behind what they find.ÌýWe’veÌýalways built WestlawÌýand Practical LawÌýwith that in mind, andÌýit’sÌýthe same principle we carried into CoCounsel Legal from the very beginning.Ìý

Built for Verification at Every StageÌý

When we designed CoCounsel Legal, we started from a simple premise: a lawyer should be able to verify everything the AI produces before putting their name on it. That meant buildingÌýtools that give attorneys everything they need to do thatÌýverificationÌýthemselves,Ìýat every stage of the workflow.Ìý

As the research unfolds,ÌýDeep ResearchÌýshows you its work in real time, step by step. You can follow the reasoning as it develops,ÌýexploreÌýfindings as theyÌýemerge, andÌýrefineÌýthe research with more specificityÌýby answeringÌýadditionalÌýquestions.ÌýÌý

As citations are built, two things work in parallel.ÌýKeyCiteÌýis woven into every stage of the research workflow, flagging cases overruled in part, warning of proposed amendments to statutes, and surfacing cases that areÌýfrequentlyÌýcited together even when theyÌýdon’tÌýcite each other. Alongside it,ÌýCoCounsel Legal’s patent-pending citation ledgerÌýtracks every source the AI draws on throughout the research process and confirms that each source wasÌýactually readÌýand reviewed — not just referenced.ÌýTogether, they give attorneys what they need toÌýanswer the questionÌýthatÌýshouldÌýprecede every citationÌýthey rely on: does this hold up?Ìý

Before anything goes out, two more layers of review engage.ÌýThe Verify function, launched in February 2026, surfaces every assertion made in the research report alongside the relevant source passages and pointers forÌýadditionalÌýresearch — giving attorneys everything they need toÌýverifyÌýbefore anything goes out the door.ÌýLitigation Document AnalyzerÌýgoes furtherÌýbyÌýidentifyingÌýpotential misrepresentations of law throughout an entire brief, your own or opposing counsel’s. Because in litigation, what a document implies about the law matters just as much as what it explicitly says.Ìý

Every one of these capabilities exists for the same reason: because when you use AI to do legal work, you are still the one responsible for it.ÌýÌý

The Question Every Lawyer Should Be AskingÌý

Not all legal AI is built the same way.ÌýSome tools are little more than general-purpose foundation models with a legal label applied — with little ability to confirm whether the underlying sources are current, authoritative, or accurately represented in the answer.ÌýThey can be fast. They can be impressive in a demo. But when a client’s matter is on the line and a judge is asking questions, impressive in a demo is not the standard that matters.Ìý

At ³ÉÈËVRÊÓƵ,Ìýfiduciary‑gradeÌýAI is our standard for how AI should work inÌýhigh‑stakes professions.ÌýÌýIt’s AI designed for professionals – built on our authoritative content; protected by rigorous privacy and security safeguards; shaped and validated by subject‑matterÌýexperts; and designed to produce transparent outputs that can be verified.ÌýÌý

We’ve spent decades earning the trust of the legal profession. That history shaped how we built CoCounsel Legal. When your firm is evaluating which AI tools to adopt, the conversation about speed and efficiency matters. But it shouldn’t be the only conversation. Ask how the system handles accuracy. Ask what happens when you need to trace an output back to its source. Ask whether you can actually verify what it produces before your name goes on it. Those questions will tell you everything you need to know about whether a tool was built for legal work or just marketed to it.Ìý

Lawyers have always been accountable for what they put their names on. The right AI gives you the tools to meet that accountability — and the confidence to know you have.

This unique advantage means we are delivering cutting-edge solutions to enable higher quality work, faster, while reflecting the needs and expectations of how professionals work today and will in the future.

However, there is not an AI system that is entirely free from the possibility of inaccuracies.

AÌýrecent caseÌýwas published from the U.S. District Court for the Central District of California that included sanctions for the submission of a brief containing numerous hallucinated citations. Through initial research to create the brief, a public large language model was used and the accuracy of several citations from the preliminary information were not verified.

Our investigation found no evidence that either CoCounsel or Westlaw was the source of the fabricated cases. We confirmed that Quick Check on Westlaw Precision identified all the issues with the erroneous quotes.

This case illustrates that despite the transformative capabilities of AI within the legal industry, .

At ³ÉÈËVRÊÓƵ, we strongly advocate for human verification of AI-generated results. That is why our customers see guidance in each of our products for a human to verify all AI generated results. And ³ÉÈËVRÊÓƵ offers multiple solutions including Quick Check on both Westlaw Edge and Westlaw Precision, KeyCite, amongst others, to help verify information.

³ÉÈËVRÊÓƵ is committed to building responsible AI solutions that legal professionals can rely on while respecting the irreplaceable qualities humans bring to the table: judgment, empathy, and understanding of human nuance. This human-centric approach to AI isn’t just good practice – it’s essential for maintaining the integrity of legal work.

This post was written by Steve Assie, general manager, Global Large Law Firms, ³ÉÈËVRÊÓƵ