CoCounsel

CoCounsel is Thomson Reuters agentic legal AI platform, originally developed by Casetext (acquired for $650M in 2023). The current product (CoCounsel Legal, launched 2025) combines pre-built legal workflows with Deep Research, an agentic system that creates research plans, executes them iteratively, and delivers reports grounded in Westlaw proprietary content. Capabilities include legal research, document drafting (privacy policies, employee policies, complaints, discovery requests), deposition transcript review, and federated search across law firm document management systems. The platform now serves 1M+ users across legal, tax, audit, and accounting professions. In legal specifically, the customer base spans the majority of Am Law 100 firms, all US federal courts, 100% of Fortune 100 companies, and 97% of Fortune 1000. Thomson Reuters is a $70B+ publicly traded company (NYSE: TRI) with a 225-year heritage in legal information. CoCounsel integrates deeply with the Thomson Reuters legal ecosystem: Westlaw (the gold standard legal research database with proprietary editorial enhancements), Practical Law (practice notes and standard documents), iManage (leading legal document management system), SharePoint, and Google Drive. The Vault feature stores up to 100,000 documents with federated search across connected firm DMS systems. Deep Research queries Westlaw content iteratively with transparent reasoning chains. Within the legal domain, Westlaw integration alone represents the deepest possible research grounding, and the addition of iManage and firm DMS connectivity means CoCounsel operates inside the tools law firms already use daily. No MCP server or public developer API is published. Pricing is subscription-based, typically bundled with Westlaw Precision. Per a Maryland State Bar Association reference, a one-attorney one-year contract for Westlaw Precision with CoCounsel runs $428/month. Actual rates vary by jurisdiction, headcount, modules selected, and contract length. Firms must engage Thomson Reuters sales for specific quotes. The bundling with Westlaw means some buyers pay for legal research infrastructure they may not need if they already use an alternative research platform. CoCounsel is designed for firms and departments already in or willing to enter the Westlaw ecosystem. Firms committed to alternative research platforms (Lexis+, vLex) will find the Westlaw bundling creates switching costs. For plaintiff-specific workflows (medical chronologies, demand letters, mass tort screening), Eve (custom pricing, $163M raised) provides deeper plaintiff lifecycle coverage. Spellbook (from $99/month) focuses specifically on contract review and negotiation. Harvey AI (custom pricing, $2B+ valuation) serves firms wanting legal AI independent of any single research database. The subscription cost with Westlaw bundling represents a significant annual commitment for smaller practices. As of Q2 2026, CoCounsel expanded from legal-only to serve tax, audit, and accounting professionals under the same brand, reaching 1M+ total users. G2 shows 75 reviews at 4.8/5 under the CoCounsel Legal profile (claimed by Thomson Reuters). The platform holds SOC 2 Type II, ISO 27001, and ISO 42001 certifications with zero-retention API architecture, no cross-client data contamination, and encrypted data in transit and at rest hosted on Azure. Customer data is never used to train models. 63% time reduction is reported for document review and contract drafting tasks. The AI Agents, Deep Research, and document drafting workflows represent the most comprehensive legal AI offering from any single vendor in the market.