CoCounsel is Thomson Reuters' professional AI legal assistant, built on the technology originally developed by Casetext before its 2023 acquisition. It handles the core knowledge work that takes up attorney time: legal research, document review, deposition preparation, and contract analysis and drafting. What sets it apart from general-purpose AI is the foundation — answers are grounded in vetted legal sources through the Thomson Reuters content library, including Westlaw, rather than open-web text. That sourcing matters for accuracy and defensibility in professional legal work. The platform is positioned squarely at legal professionals who need reliable, citation-backed output rather than a general chatbot experience. Enterprise-grade security and integration with the broader Thomson Reuters research ecosystem make it a credible fit for law firms and in-house legal teams. Smaller or solo practices should verify plan pricing before committing, as the platform is built around professional-grade use cases that may carry corresponding costs.