CoCounsel was the darling of the then-nascent legal AI market, offering to improve the efficiency and effectiveness of legal services. After officially launching in March 2023, CoCounsel quickly gained momentum for its ability to review files, conduct legal research and draft documents. It caught the eye of Thomson Reuters, which acquired CoCounsel for $650 million in June 2023 after noticing its growing acceptance among law firms.
"The hype around the tools when they launched exceeded the capabilities of the tools," Tom Trujillo, McGuireWoods' chief innovation and AI officer, told Law360 Pulse.
After a one-year pilot in 2023, McGuireWoods felt it needed more time to continue testing the tool. The firm signed another one-year contract with CoCounsel in 2024.
By 2025, however, Trujillo noticed that the market — and the tools — had evolved. Newer AI assistants such as Harvey and Legora had taken the legal market by storm, creating more choices for law firms. The firm saw an opportunity to reevaluate its AI strategy.
"We thought the responsible thing was to step back and make sure that we're being as objective as possible about what's the right decision for our firm," Trujillo said.
McGuireWoods launched a competition this past summer with CoCounsel, Harvey and Legora. About 150 of the firm's 1,000 attorneys joined the pilot program to test the tools' capabilities and gather qualitative feedback from participants.
Trujillo said the attorneys "overwhelmingly" favored Harvey and Legora over the incumbent platform CoCounsel. The firm stopped using CoCounsel at the end of the summer.
Trujillo said that CoCounsel is a great tool, but the firm's users preferred Harvey and Legora because their interfaces were slightly easier to use and the workflows seemed a bit more advanced.
Legal generative AI platforms can be pricey, and while major players are not publicly forthcoming with pricing, experts say the major tools cost roughly the same.
McGuireWoods wasn't the only early adopter to drop CoCounsel and turn to competitors.
London-based Addleshaw Goddard LLP, another early adopter in 2023, stopped using CoCounsel in April of this year. Michael Kennedy, Addleshaw Goddard's head of innovation and legal tech, said the firm switched to Legora because it filled more of a business need, but did not respond to a question about further specifying the reasons for the change.
"As this market is moving so rapidly, we are keeping a close eye on things and constantly considering which solutions best fulfill the needs of the firm and our clients," Kennedy said.
Kennedy said the firm would not rule out going back to CoCounsel in the future.
The Employment Law Center of Maryland, a nonprofit law firm that was featured in a 2023 Associated Press article for adopting CoCounsel, stopped using the tool. It now uses OpenAI's ChatGPT, as well as Microsoft Copilot for various discovery tasks.
San Francisco-based Orrick Herrington & Sutcliffe LLP, another early adopter that advised Casetext on its acquisition by Thomson Reuters, declined to comment on the status of CoCounsel in the firm.
Based on internal records, Thomson Reuters claims it experienced only two cancellations among the first 23 BigLaw firms to subscribe to CoCounsel. Thomson Reuters said it didn't have permission to name all 23 firms that supposedly subscribed to the tool.
"That's a few isolated examples from my experience," said Laura Safdie, the former chief operating officer and general counsel of Casetext, who now serves as the head of legal innovation at Thomson Reuters. "By no means a trend and not something that we're concerned about."
Most of CoCounsel's early adopters haven't left, and CoCounsel's customer base has grown, according to Safdie, who said there are now over 700,000 professionals who use at least one of the company's legal AI products.
While not minimizing the customer departures, Safdie described them as an "isolated few."
Safdie said that some firms will switch to CoCounsel after trying other tools first, and others will try CoCounsel before jumping to another solution.
Many early adopters still use CoCounsel today along with other tools. London-based DLA Piper still uses CoCounsel and added Harvey to its AI tool kit. Atlanta-based Fisher Phillips still uses CoCounsel along with other AI tools such as Vincent AI and Hebbia.
"It reflects the experimentation happening in the market," Safdie said.
About 36% of law firms are currently using the "Core" CoCounsel tool, the second most popular generative AI tool in law firms today after Microsoft 365 Copilot, according to a September 2025 survey from the International Legal Technology Association, or ILTA. Core is a stand-alone version with document analysis capabilities and differs from CoCounsel Legal, the newest and most comprehensive offering of the tool that launched in August.
However, only about one in four law firms with the "Core" CoCounsel tool have fully deployed it to attorneys or staff. By comparison, while just 25% of law firms have Lexis+ AI from LexisNexis, nearly half of those firms have fully deployed it, according to that survey.
Firms using CoCounsel are taking a more conscious and intentional rollout approach based on needs, according to Safdie. She added that Thomson Reuters is now seeing more movement from pilots to firmwide deployment.
As for the early adopters who stopped using CoCounsel, Safdie said there's an expectation that some might return in the future.
Even as McGuireWoods rolls out Harvey and Legora right now, Trujillo said it's possible the firm could return to CoCounsel in the future.
"The market is just changing so fast every day," Trujillo said. "A year from now, CoCounsel could be the lead dog again."
--Additional reporting by Matt Perez. Editing by Robert Rudinger.
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