Thomson Reuters (TRI) has launched early access to the next generation of CoCounsel Legal, the most significant reworking of its flagship legal AI assistant since acquiring Casetext in 2023.
Alongside that launch, the company released its Future of Professionals Report 2026, which identifies a growing divide between AI adoption rates and the actual value organisations are extracting from it.
Thomson Reuters President and CEO Steve Hasker described the new CoCounsel as the first version to genuinely unlock the value of Westlaw, Practical Law, and the expertise of 2,700 attorney-editors in training the agent.
Hasker said the prior version of CoCounsel did not achieve that integration, calling the new release “a huge step forward for the industry relative to anything else they’ve seen or been looking at.”
The accelerated release was driven by an exceptionally strong beta trial, with Hasker describing it as “the most successful beta trial I’ve ever been a part of, by a long way, in terms of the feedback on the utility of the product, the accuracy of the product, and also the reliability.”
CoCounsel is built on the same architecture as Westlaw Advantage, which launched last summer, with largely the same team of technologists, researchers, scientists, and product engineers ported across to rebuild the product.
Thomson Reuters has partnered with Anthropic, using the Claude SDK as a foundation for its agentic AI products, though Hasker confirmed the company is building its architecture to remain model-agnostic so it can use the best available models on an ongoing basis.
The company is also in advanced testing of its own large language model, called Thomson, developed following the acquisition of a research lab called Safe Sign Technologies, which was centred around Cambridge University and has since been extended to Imperial College in London.
Hasker said Thomson “is starting to outperform all of the latest models for specific legal tasks,” adding that the company has not yet decided whether some or all aspects of CoCounsel will run on Thomson alongside the Claude SDK.
On the concept of fiduciary-grade AI, Hasker was direct, stating it “should be common to all legal products but is not currently,” pointing to recent high-profile hallucination cases involving well-regarded firms using frontier models without access to authoritative legal content.
Thomson Reuters differentiates its offering through strict data-governance standards, with Hasker emphasising that “the proposition we put in front of our customers is that their input will not become part of our AI output,” a stance he acknowledged is “antithetical to the Silicon Valley ethos.”
The company also offers customers the ability to speak directly with a reference attorney who can replicate any query in the tool and explain exactly how it reached its conclusion, providing a level of transparency Hasker described as “about as far from a black box as we could currently design.”
Hasker said the transparency built into CoCounsel could serve as an important part of the next generation of legal apprenticeships, helping junior lawyers understand the steps and citations behind every conclusion the tool reaches.
The Future of Professionals Report 2026 found that 78% of corporate clients say AI-enabled quality improvements are very important or essential, yet only 6% say their outside counsel are delivering on that expectation.
One managing partner told Hasker directly that “the tools are 18 months ahead of the change management,” reflecting a broader finding that law firms are experimenting with AI without yet rethinking underlying workflows, roles, or performance measures at the firm-wide level.
Hasker noted a marked increase in assertiveness from general counsel at Thomson Reuters’ Legal Executive Briefing at Pebble Beach, where 75 general counsel attended and signalled plans to consolidate panel firms and expect AI benefits to flow through in billing, quality, and speed.
Despite broader concerns about the impact of AI on the legal profession, Hasker expressed optimism, arguing that AI will drive an uptick in demand for legal services over time, much like previous major technology breakthroughs have historically increased economic activity.