Casetext CoCounsel

CoCounsel is an AI legal assistant originally built by Casetext on top of GPT-4 and now owned by Thomson Reuters. It provides task-specific legal skills — legal research, document review, contract analysis, deposition preparation, summarization, and drafting — rather than a generic chat experience. It is grounded in Thomson Reuters's legal content, including Westlaw and Practical Law, which makes its answers more authoritative than pure foundation-model outputs.

No, but they are increasingly integrated. Westlaw is Thomson Reuters's primary legal research platform with an enormous database of case law, statutes, regulations, and secondary sources. CoCounsel is the AI assistant layer that can read Westlaw content, answer questions, summarize authorities, and perform document review tasks. Since the Thomson Reuters acquisition, the two products have been aligned and many firms buy them together as part of a single contract.

Thomson Reuters acquired Casetext in August 2023 for approximately $650 million. Since then, CoCounsel has been integrated with Thomson Reuters's legal research and practical law platforms and is sold through Thomson Reuters's enterprise sales force. The acquisition was one of the largest legal tech deals in history and cemented Thomson Reuters's position as a serious player in generative AI for the legal profession.

Thomson Reuters does not publish CoCounsel pricing. Industry reports place it in the ballpark of $225–$500 per lawyer per month depending on bundling and firm size. Most mid-size and large firms buy CoCounsel as part of a broader Westlaw and Practical Law subscription, which often makes the incremental cost of adding AI features more palatable than standalone pricing would suggest.

Yes. CoCounsel is SOC 2 Type II compliant and backed by Thomson Reuters's enterprise security and legal risk infrastructure. It does not train its base models on customer data, supports access controls, and signs enterprise agreements appropriate for privileged and confidential client matters. Large law firms have completed security reviews and deployed CoCounsel across hundreds or thousands of lawyers without incident.

Harvey is positioned as the premium enterprise AI workflow platform for large law firms and professional services. CoCounsel leads on legal research grounded in Thomson Reuters content and a mature library of specific skills. Firms often use both: Harvey for broad workflow automation and drafting, CoCounsel for research and Westlaw-backed answers. For firms already standardized on Thomson Reuters, CoCounsel tends to be the natural first AI investment.