Thomson Reuters has launched the next generation of CoCounsel Legal, now generally available in the United States.
The updated AI tool is designed to take lawyers from research and issue analysis to draft work product within a single workflow. It also includes Westlaw Brief Builder, a new feature aimed at litigators preparing first-draft briefs.
The launch reflects a broader push to link Thomson Reuters' legal research and drafting tools more closely. CoCounsel Legal now brings together research, drafting, legal intelligence, verification and matter-based workflows in one environment.
At the centre of the update is an agentic AI model built to handle multi-step legal tasks rather than answer one prompt at a time. The system is grounded in Westlaw and Practical Law content and produces citation-backed results with traceable legal authority.
Raghu Ramanathan, President, Legal Professionals, Thomson Reuters, said law firms and in-house teams are changing how they judge AI products.
"The legal industry is moving beyond AI that simply generates answers," said Raghu Ramanathan, President, Legal Professionals, Thomson Reuters. "Whether you're at an Am Law 100 firm, a midsize or small practice, or a corporate legal department, the challenge is the same: turning insight into action. The next generation of CoCounsel Legal helps professionals complete legal work with confidence by combining trusted legal content, agentic intelligence, and workflow execution in a single experience. That's a fundamentally different approach to legal AI and a major step forward for the profession."
Brief drafting
Westlaw Brief Builder is the most prominent addition in the release. It uses Westlaw Deep Research, KeyCite and Practical Law to help litigators move from legal research and issue analysis to a first draft while checking supporting authority as they work.
The feature proposes relevant facts, arguments and authority, while leaving legal strategy and final decisions to lawyers.
Jennifer Eng, Shareholder, Commercial Litigation, Polsinelli, described the tool as a step beyond question-and-answer systems.
"What sets the new CoCounsel Legal apart is that it doesn't just answer questions; it builds toward real work product," said Jennifer Eng, Shareholder, Commercial Litigation, Polsinelli. "Its grounding in Westlaw gives me confidence that the research is authoritative, while the agentic workflow carries that analysis through reasoning, drafting, and verification. As a litigator, I need speed without sacrificing precision, and this is the first tool that gets me from a complex legal question to a defensible draft, faster and with real confidence, which is not a small shift."
Wider workflow
Alongside Brief Builder, Thomson Reuters outlined several other additions. Workspaces creates a matter-specific environment that combines internal documents, precedents and institutional knowledge, allowing legal teams to carry context across tasks without starting from scratch each time.
It also expanded drafting functions in Microsoft Word through a Drafting Agent in CoCounsel for Word. Lawyers can use natural language instructions to draft, edit and review agreements while drawing on Practical Law materials as well as their own organisational documents and playbooks.
Another feature, Tabular Analysis, is aimed at large-scale document review. It allows lawyers to review up to 10,000 documents and ask up to 100 questions, with results shown in a filterable table. The feature runs on Thomson Reuters' legal-focused large language model.
Deep Research Verify is intended to test whether cited Westlaw and Practical Law authority supports specific legal assertions. In practice, users can check whether a proposition in AI-assisted work is backed by the sources it cites.
Emily Colbert, SVP, CoCounsel Litigation, Thomson Reuters, said the brief-writing tool was designed to support legal reasoning rather than replace it.
"A brief is only as strong as the thinking behind it," said Emily Colbert, SVP, CoCounsel Litigation, Thomson Reuters. "Westlaw Brief Builder was built to support that thinking, not replace it, by transforming how litigators research, test, and refine their arguments at every stage, from spotting the right issues to backing them with authoritative law. The goal is not to simply generate a document faster; it's to help lawyers build a stronger, more defensible case they're confident standing behind in court."
Market pressure
The launch comes as legal software groups compete to turn generative AI into practical tools for fee earners and in-house counsel. Thomson Reuters said the market is moving beyond experimentation, with buyers increasingly focused on source reliability, accountability and whether software can support substantive legal work.
According to Thomson Reuters, one million professionals across 107 countries and territories now use CoCounsel. While the new CoCounsel Legal experience is available in the United States, availability in Canada, the United Kingdom and Australia is expected later this year.
Thomson Reuters is also continuing work with Anthropic, whose Claude Agent SDK underpins the product, and expanding its collaboration with AWS. An integration with Reveal will allow litigation teams to bring reviewed evidence into CoCounsel Legal for research, analysis and drafting without manually exporting and re-uploading documents.