CoCounsel Pros & Cons: What Nobody Tells You [2026]

It is the evolution of it. Thomson Reuters acquired Casetext in 2023 and has since rebuilt and expanded the product, integrating it across Westlaw Precision, Practical Law, and Checkpoint, and rebranding the broader AI strategy under the CoCounsel name. The standalone offering is now called CoCounsel Core.

CoCounsel is engineered to mitigate hallucinations by grounding responses in Westlaw's editorially curated database and returning verifiable citations with each answer. While no generative AI is fully immune to errors, hallucinated citations are far less common than with general-purpose LLMs, and lawyers are expected to verify outputs using KeyCite before relying on them.

Thomson Reuters operates CoCounsel in a secure enterprise environment with SOC 2 Type II compliance and encryption in transit and at rest. Customer prompts, uploaded documents, and outputs are not used to train Thomson Reuters' or third-party foundation models, supporting compliance with ABA Model Rule 1.6 confidentiality obligations.

Harvey is platform-agnostic and oriented toward large law firms with bespoke deployments, while CoCounsel's primary advantage is its tight coupling with Westlaw's authoritative legal database and Practical Law's templates. Firms that prioritize citation accuracy and live in Westlaw will favor CoCounsel; firms that want a more flexible AI layer across multiple data sources may prefer Harvey.

Thomson Reuters does not publish pricing. CoCounsel is sold as an enterprise product, typically bundled with or added to Westlaw Precision and Practical Law subscriptions. Pricing is negotiated based on firm size, seat count, and which skills and integrations are included.