CoCounsel Legal is Thomson Reuters' AI assistant for legal research, document review and drafting, grounded in Westlaw and Practical Law with citations you can click and check. It is our first choice for small firms that want AI they can verify, but prices are not published, so its value depends on the quote you get. You still need to read every case it cites.
What CoCounsel Legal is
CoCounsel Legal is an AI assistant for lawyers from Thomson Reuters, the company behind Westlaw and Practical Law Thomson Reuters ↗. You describe what you need in plain language, and it builds a step by step plan you can inspect before it researches, analyzes and drafts Thomson Reuters ↗.
Its answers draw on Westlaw primary law, Practical Law guidance and your own firm's documents, with linked citations so you can verify each point Thomson Reuters ↗. Workspaces keep documents, templates, conversations and matter history together so you can pick a matter back up later Thomson Reuters ↗. Thomson Reuters markets it to solo practitioners and small firms as well as larger ones Thomson Reuters ↗.
What it does well
Grounding is the main reason to choose it. A general chatbot can invent a case. A tool tied to a real legal database, with links you can click, is easier to check Thomson Reuters ↗. That is why we rank it first for small firm research and drafting.
It covers the jobs a small litigation or transactional practice does every week. Westlaw Brief Builder supports brief writing from framing the issue to structuring the argument, while the attorney reviews facts, picks arguments and validates citations Thomson Reuters ↗. Tabular Analysis can review up to 10,000 documents against 100 questions, with results in one sortable table and answers traced to the source Thomson Reuters ↗. Deep Research and a Litigation Document Analyzer are also listed Thomson Reuters ↗.
It fits into tools lawyers already use. It works in Microsoft Word, Outlook and Teams and connects to iManage, NetDocuments, SharePoint, Box, Smokeball, Litify and other systems Thomson Reuters ↗. There is also an MCP connection for Claude Thomson Reuters ↗.
Security claims are solid. Thomson Reuters says CoCounsel Legal is SOC 2 and ISO 42001 certified and that it never uses client data to train the underlying models Thomson Reuters ↗. It also cites a Forrester study, commissioned by Thomson Reuters, reporting a 33 percent average cut in time spent on review, research and drafting Thomson Reuters ↗. Treat vendor funded numbers with caution. Hands on testing is in progress.
Where it falls short
Prices are not published. The product page sends you to a plans page and to sales, and offers a free demo rather than a free trial Thomson Reuters ↗. That makes it hard to compare with tools that list a price.
Grounding does not mean error free. A Stanford study published in May 2024 found that Thomson Reuters' earlier Westlaw AI-Assisted Research tool hallucinated more than 34 percent of the time on its test questions, and Ask Practical Law AI gave incorrect information more than 17 percent of the time Stanford HAI ↗. The researchers concluded that linking AI to legal sources does not fully fix made up answers Stanford HAI ↗. CoCounsel Legal is a newer product, but the lesson stands: read every authority it cites before you rely on it.
It is also a research and drafting tool, not practice management. You will still need separate software for billing, calendars and client intake.
Pricing and plans
Thomson Reuters does not list prices for CoCounsel Legal on its product page Thomson Reuters ↗. It links to plan pages for law firms, corporate counsel and government Thomson Reuters ↗.
The plans it names for smaller firms include Westlaw Edge, Westlaw Advantage, CoCounsel Essentials and several tiers of CoCounsel Legal Thomson Reuters ↗. Which features each tier includes, and what it costs, comes through sales Thomson Reuters ↗.
There is no free trial listed. You can request a free demo or try an interactive demo Thomson Reuters ↗. Ask for written terms on contract length, number of users and price increases at renewal before you sign.
Who should (and shouldn't) use it
- Good fit: small firms that want research and drafting backed by Westlaw with citations they can check.
- Good fit: litigators who review large document sets and write briefs.
- Good fit: firms already paying for Westlaw or Practical Law.
- Skip it if: you need a published price before talking to sales.
- Skip it if: you mainly want AI inside case management and billing software.
Alternatives worth a look
- MyCase: AI inside practice management software, with AI plans from $100 per user a month billed yearly MyCase ↗.
- Clio: practice management and legal AI from one large vendor, from $49 per user a month Clio ↗.
- Spellbook: AI contract review inside Microsoft Word, with a 7 day free trial Spellbook ↗.
Where it appears
Our pickThe Best AI Tools for Lawyers at Small FirmsWhat’s good
- Grounded in a major legal database
- Works inside Office
- Client data not used for training
What to know
- No published price
- AI research errors found in earlier Thomson Reuters tools
Key features
- Research grounded in Westlaw and Practical Law with linked citations
- Inspectable step by step plans
- Westlaw Brief Builder
- Tabular Analysis of up to 10,000 documents
- Works in Word, Outlook and Teams
Works with
Questions people ask
How much does CoCounsel Legal cost?
Thomson Reuters does not publish the price. You request a quote or demo through its plans page and sales team Thomson Reuters ↗.
Does CoCounsel Legal have a free trial?
No free trial was listed when we checked. Thomson Reuters offers a free demo and an interactive demo Thomson Reuters ↗.
Is CoCounsel Legal accurate?
It grounds answers in Westlaw and Practical Law with linked citations, but a 2024 Stanford study found frequent errors in earlier Thomson Reuters AI research tools, so check every citation Thomson Reuters ↗ Stanford HAI ↗.
Does CoCounsel Legal use my client data for training?
Thomson Reuters says it never uses customer data to train the underlying models and that the product is SOC 2 and ISO 42001 certified Thomson Reuters ↗.
Where this comes from
Checked Oct 9, 2026. Vendor pages describe their own products; independent sources add outside views. Hands on testing is in progress.
01