Thomson Reuters is expanding its partnership with Anthropic to bring CoCounsel Legal directly into Claude workflows, a move the company says will help legal professionals bridge the gap between general-purpose AI and citation-grounded legal work.
The Toronto-based global content and technology company announced today a new Model Context Protocol integration that connects Anthropic’s Claude with CoCounsel Legal. The integration allows legal professionals to move between Claude and CoCounsel Legal, bringing Thomson Reuters’ legal content, workflows, and citation-backed outputs into AI-assisted work environments.
As legal AI adoption accelerates, Thomson Reuters says the market is confronting a growing divide between the speed and convenience of general-purpose AI tools and the accuracy, traceability, and accountability required for legal work.
CoCounsel Legal is designed to address that gap. The platform reasons across 1.9 billion Westlaw and Practical Law documents, 1.4 billion KeyCite validity signals, and a patent-pending citation ledger that makes every source traceable in one click.
“Thomson Reuters is building CoCounsel Legal to be the fiduciary-grade system at the center of how legal work gets done, connected to the tools lawyers use and built to the standard their work demands,” said David Wong, Chief Product Officer at Thomson Reuters.
Wong said the Claude integration is one example of how Thomson Reuters expects those connections to grow as it moves toward general availability for the next generation of CoCounsel Legal this summer.
That next generation is being rebuilt on Anthropic’s Claude Agent SDK. According to Thomson Reuters, the system is designed to plan, select tools, retrieve authoritative content, and adapt mid-workflow. Lawyers will be able to describe a matter in plain language and have CoCounsel Legal pursue the appropriate inquiry, draft with citations, and include validated references in the final work product.
“Our work with Thomson Reuters reflects a deeper strategic partnership to deliver AI that can operate in high-stakes professional environments,” said Scott White, Head of Product, Enterprise at Anthropic. “Integrating Claude with CoCounsel Legal brings together leading AI with trusted legal content and workflows, enabling users to move from exploration to execution with confidence.”
For Thomson Reuters, the integration also reflects a broader strategy: making CoCounsel available wherever legal professionals are working, rather than requiring users to choose between general-purpose AI and legal-specific systems.
“Legal professionals deserve AI they can trust with their most important work,” said Joel Hron, Chief Technology Officer at Thomson Reuters. “In professional environments, trust in AI is a property of the system itself, built into the architecture and verifiable at every step.”
Hron said Thomson Reuters is actively building integrations that connect general-purpose AI to professional environments, with the Claude integration representing the first place lawyers will experience that approach.
The announcement builds on Thomson Reuters’ long-standing position in legal information through Westlaw, Practical Law, and KeyCite. The company says more than 2,600 attorneys and legal specialists help shape how CoCounsel reasons and produces outputs.
Thomson Reuters also emphasized that customer data is not used to train third-party models and is not shared beyond a customer’s own environment, a commitment the company framed as essential in a profession where confidentiality is both a legal and ethical obligation.
The company says one million professionals across 107 countries and territories now use CoCounsel and Thomson Reuters AI technology.