CoCounsel is Thomson Reuters’ AI legal research assistant, built on the Casetext platform acquired for $650M in 2023. It combines GPT-powered legal AI with Westlaw’s case law database — the first major integration of generative AI into a traditional legal research platform.
Previously known as Casetext, which challenged the legal research market with Parallel Search (AI-powered concept matching) and pricing that undercut Westlaw and LexisNexis. Now bundled with Westlaw as CoCounsel, the standalone pricing advantage is gone, but the AI capabilities have expanded significantly.
What It Does
- Legal research — AI-powered case law search across 50 states and federal courts
- Contract review — Automated clause analysis and risk flagging
- Document review — Concept-based search across document sets (AllSearch)
- Brief drafting — AI-assisted memo and brief generation
- Deposition preparation — Automated question generation from case files
Who It’s For
10,000+ organisations from solo practitioners to Am Law 200 firms. Now positioned as the AI layer on top of Westlaw, targeting both existing Thomson Reuters customers and new adopters looking for AI-assisted research.
What We Haven’t Verified
- Current pricing structure post-acquisition (standalone vs. Westlaw bundle)
- Accuracy benchmarks for AI-generated legal research vs. manual Westlaw search
- Whether the original Casetext standalone product remains available
Workflows
Based on practitioner evidence, CoCounsel is used in these workflows:
What practitioners struggle with
Real frustrations from legal professionals — the problems CoCounsel addresses (or should address). Sourced from practitioner reviews, Reddit threads, and case studies.
Legal research costs $400-600/hour in associate time and takes hours of manual digging — searching Westlaw/Lexis, reading irrelevant results, synthesizing case law. Clients increasingly refuse to pay for research hours on invoices. AI can compress a 4-hour research memo into 20 minutes, but most firms have no approved tool
Law firm knows attorneys are quietly using ChatGPT for legal work — risk of hallucinated citations (Mata v. Avianca sanctions), client confidentiality breaches, and bar ethics complaints. Firm needs a secure, approved AI platform with ethical walls, data isolation, and audit trails, not a ban that everyone ignores
Solo/small firm needs case law research but Westlaw and LexisNexis charge $300-500/month per user — either pay and bleed, negotiate a discount every year, or go without and risk missing relevant authority. Free alternatives (Google Scholar, Fastcase) have gaps in coverage and no citator
Where it fits in your workflow
Before CoCounsel
Attorney has legal research question → opens CoCounsel (via Westlaw or standalone) → describes the issue in natural language → CoCounsel searches Westlaw's case law + statutory databases
After CoCounsel
CoCounsel generates research memo with cited authorities → attorney verifies citations → incorporates findings into brief/motion/memo → also: contract analysis, document review, due diligence tasks via agentic AI capabilities (Aug 2025 launch)
Integrations & hand-offs
CoCounsel → Westlaw (integrated case law database). CoCounsel → attorney workstation (research output). CoCounsel Legal (Aug 2025) → agentic AI with deep research capabilities. Thomson Reuters ecosystem → Practical Law, Drafting Assistant (cross-product). No integration with non-TR research platforms.
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Community Data
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