CoCounsel

CoCounsel is Thomson Reuters' AI legal research assistant, powered by their proprietary AI and integrated with the Westlaw legal database. Starting April 2026, CoCounsel will be included with Westlaw Advantage subscriptions, making it accessible to the existing Westlaw user base without additional cost. The platform's standout feature is Deep Research, an agentic AI capability that conducts multi-step legal research autonomously. Rather than answering a single query, Deep Research plans a research strategy, executes multiple searches, synthesizes findings, and delivers comprehensive research memos with citations. It can also analyze documents up to 300 pages and draft legal documents. CoCounsel targets all firm sizes through its inclusion in Westlaw Advantage. For firms already paying for Westlaw, CoCounsel represents significant added value. The platform was originally developed by Casetext, which Thomson Reuters acquired, bringing together Casetext's AI expertise with Westlaw's unmatched legal database.