Overview
CoCounsel is Thomson Reuters' AI legal assistant, built on GPT-4 combined with Thomson Reuters' proprietary legal content — including Westlaw's case law database and Practical Law's practice resources. It operates as a conversational interface that executes complex legal tasks when given plain-language instructions. CoCounsel's core capabilities include document review, legal research, deposition preparation, contract analysis, and contract drafting. For document review, attorneys upload a document set and ask CoCounsel to identify specific issues — privilege concerns, breach triggers, or particular fact patterns — across hundreds of documents simultaneously. The platform returns organized results with source citations rather than leaving review to manual assessment. For legal research, CoCounsel queries Westlaw's verified database rather than the open web, eliminating hallucinated citations. Deposition preparation is a standout feature: CoCounsel generates targeted question outlines based on prior testimony, expert reports, or contract terms. Contract analysis identifies non-standard provisions and potential risk items against a specified playbook. CoCounsel is available as a standalone subscription and as an add-on within Westlaw. Thomson Reuters has announced deep integration between CoCounsel and its broader product ecosystem, including HighQ and Practical Law. Best for mid-size to large law firms and corporate legal departments performing high-volume work.
Key features
Legal Research with Verified Citations
Ask legal questions in natural language; receive structured answers citing KeyCite-verified Westlaw authorities. Significantly faster than Boolean searching for preliminary research.
Contract Review Against Checklist
Upload a contract and a review checklist (or use a standard one), and CoCounsel flags issues, identifies missing provisions, and summarizes findings. Reduces time from playbook to first markup.
Deposition and Document Summarization
Summarize deposition transcripts, expert reports, or large document productions. Extracts key facts, contradictions, and relevant testimony into structured summaries.
Research Memo Drafting
Generate a structured research memo draft with citations from a legal question. Requires attorney editing but addresses the blank-page problem for initial drafts.
Multi-Document Q&A
Upload a set of documents and ask questions across them — useful for reviewing deal data rooms, discovery productions, or regulatory submissions.
Westlaw Integration
Works directly within the Westlaw interface — research results, citations, and KeyCite status are available without leaving the platform.
Pros and cons
Pros
- Grounded in Westlaw with KeyCite verification — lower hallucination risk on legal citations than ungrounded AI tools
- Contract review against a custom checklist saves hours on due diligence — go from playbook to markup faster
- Deposition and transcript summarization handles large document volumes that would take associates hours to digest
- Research memo drafting from a legal question is faster than blank-page drafting, even accounting for review time
- Seamlessly integrated with Westlaw — no separate context-switching for Westlaw users
Cons
- Sold as a premium add-on to an already-expensive Westlaw subscription — combined cost is significant
- AI outputs require mandatory attorney review — cannot substitute for legal judgment
- Lags Harvey on breadth of legal drafting tasks beyond research and document review
- No published pricing — requires a sales conversation
- Only available to Westlaw subscribers — firms on LexisNexis-only cannot access it
Pricing
Pricing current as of May 2026; verify with vendor before purchasing.
Who it's best for
Best fit for
- Westlaw subscribers wanting AI-accelerated research, memo drafting, and document review
- Litigators who do heavy contract or deposition review work on each matter
- Associates doing initial research and due diligence who need a structured starting point
- Firms already in the Thomson Reuters ecosystem wanting AI without switching platforms
Not a fit for
- Firms on LexisNexis-only subscriptions (use Lexis+ AI instead)
- Attorneys needing broad legal drafting and deal AI beyond research (Harvey covers more ground)
- Solo and small firm attorneys who cannot justify the combined Westlaw + CoCounsel cost
- Anyone expecting AI to replace attorney review — not suitable for that use case
Frequently asked questions
CoCounsel does not publish pricing. It is sold as a premium add-on to a Westlaw subscription. Contact Thomson Reuters sales for firm-specific pricing.
More accurate than general-purpose AI for legal research because it is grounded in Westlaw and cites KeyCite-verified authorities. Attorney review is still required — no AI legal tool is reliable enough to use without verification.
CoCounsel is stronger for legal research (Westlaw grounding) and document review against a checklist. Harvey has broader capabilities including drafting, M&A due diligence, and custom workflows. Large BigLaw firms often use both.
Both are AI research assistants grounded in legal databases with citation verification. CoCounsel uses Westlaw and KeyCite; Lexis+ AI uses LexisNexis and Shepard's. CoCounsel is generally considered stronger for document review capabilities.
Yes. CoCounsel is a Westlaw add-on and requires an active Westlaw subscription.