Westlaw Advantage is the AI-forward tier of Thomson Reuters' Westlaw research platform, sitting alongside — and distinct from — the CoCounsel assistant. It keeps the traditional Westlaw apparatus (KeyCite, the West Key Number System, headnotes) and layers agentic AI skills on top of it.
The headline features are Deep Research, which plans and runs a multi-step investigation and returns a full report with cited sources; Claims Explorer, which takes the facts of a matter and returns candidate causes of action (Thomson Reuters reports attorneys in testing found relevant claims three times faster than with traditional research); Litigation Document Analyzer, which goes beyond citation checking to surface mischaracterizations of law, hallucinated cases, and likely opposing arguments in a brief; Complaint Analyzer; and AI Jurisdictional Surveys.
Westlaw Advantage is sold across firms of all sizes, corporate legal departments, and courts and government agencies — Thomson Reuters reports Westlaw is used by 94% of U.S. state courts. CoCounsel Legal and CoCounsel Essentials are sold as complementary products, and this listing covers the research platform rather than that assistant.
Unusually for enterprise legal AI, Thomson Reuters publishes self-serve rates for small firms: $256.75/month for single-circuit coverage and $399.75/month for all states plus federal, for firms up to 10 attorneys, with 12% off a two-year and 18% off a three-year subscription. Firms with 11 or more attorneys get a sales quote. Thomson Reuters does not itemize which foundation models power each AI skill.