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.
That’s why when firms talk about adopting AI for legal work, the first question shouldn’t be about speed or cost savings. It should be: can I actually verify what this produces? If you can’t trace an output back to its source, check whether that source is still good law, and inspect the reasoning that connected the two, you don’t have work product. You have a draft you can’t stand behind.
That standard is not new. What’s new is how many lawyers are finding out the hard way that the AI tools they adopted weren’t built with it in mind.
Courts across the United States have now sanctioned attorneys for submitting briefs 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 sources maintained by 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 citation actually supports the argument it’s being used to make. Verification becomes difficult not because the tools don’t show their work, but because the underlying sources can’t be trusted in the first place.
At Thomson Reuters, we understand that lawyers don’t just need to find the law — they need to be able to stand behind what they find. We’ve always built Westlaw and Practical Law with that in mind, and it’s the same principle we carried into CoCounsel Legal from the very beginning.
Built for Verification at Every Stage
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 building tools that give attorneys everything they need to do that verification themselves, at every stage of the workflow.
As the research unfolds, Deep Research shows you its work in real time, step by step. You can follow the reasoning as it develops, explore findings as they emerge, and refine the research with more specificity by answering additional questions.
As citations are built, two things work in parallel. KeyCite is woven into every stage of the research workflow, flagging cases overruled in part, warning of proposed amendments to statutes, and surfacing cases that are frequently cited together even when they don’t cite each other. Alongside it, CoCounsel Legal’s patent-pending citation ledger tracks every source the AI draws on throughout the research process and confirms that each source was actually read and reviewed — not just referenced. Together, they give attorneys what they need to answer the question that should precede every citation they rely on: does this hold up?
Before anything goes out, two more layers of review engage. The Verify function, launched in February 2026, surfaces every assertion made in the research report alongside the relevant source passages and pointers for additional research — giving attorneys everything they need to verify before anything goes out the door. Litigation Document Analyzer goes further by identifying potential 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.
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.
The Question Every Lawyer Should Be Asking
Not all legal AI is built the same way. Some 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. They 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.
At Thomson Reuters, fiduciary‑grade AI is our standard for how AI should work in high‑stakes professions. It’s AI designed for professionals – built on our authoritative content; protected by rigorous privacy and security safeguards; shaped and validated by subject‑matter experts; and designed to produce transparent outputs that can be verified.
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.
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.
