MCP Connector
CoCounsel Legal
Thomson Reuters' AI for legal professionals, in Claude
What is the CoCounsel Legal MCP Connector?
The CoCounsel Legal MCP Connector brings Thomson Reuters CoCounsel Legal into Claude. CoCounsel Legal is Thomson Reuters' AI for legal professionals, designed to work at the level of a senior associate, with Westlaw and Practical Law content natively embedded in how it reasons.
Deep legal research is the first CoCounsel Legal capability available in Claude. Attorneys can launch jurisdiction-aware research runs across US federal and state law, monitor agent progress, retrieve fully cited reports with Westlaw source links, and ask follow-up questions in the same conversation. Coverage spans statutes, case law, regulations, secondary sources, and Practical Law commentary, with every citation linked back to authoritative Thomson Reuters content for verification.
Additional CoCounsel Legal capabilities will be added to the same connector over time. You will not need to reconnect or reinstall, new tools become available automatically as they ship.
What you can do with it today
- Use CoCounsel Legal to run jurisdiction-aware deep legal research on a question and receive a cited memo.
- Compare treatment of an issue across up to three US jurisdictions in a single research run.
- Return to a completed research conversation and retrieve the report later in Claude.
- Ask a follow-up question against an existing research conversation without restarting.
Set up in Claude Desktop
- Open Claude Desktop and sign in to your Claude account.
- Go to Settings → Connectors.
- Search for CoCounsel Legal and click Connect.
- When the Thomson Reuters sign-in window opens, complete the sign-in and authorize the connector. You only need to do this once.
- CoCounsel Legal will now appear in the connectors menu inside your Claude conversations and is ready to use.
Once connected, describe the legal research you want done in plain English. Claude will pick the right CoCounsel Legal tool for you.
Available tools
Today, the CoCounsel Legal connector exposes deep legal research through four tools. Claude calls them on your behalf, you do not need to invoke them by name.
| Tool | What it does | Example use |
|---|---|---|
| Start Deep Legal Researchstart_deep_research | Start a new deep legal research session for the given query with optional US jurisdiction targeting. Returns a conversation reference used to poll status and retrieve the final report. | "Research how California courts have treated non-compete agreements for executive employees since 2020." |
| Check Deep Research Statuscheck_deep_research_status | Check the progress of an ongoing deep legal research session. Returns the current research plan and percent complete. | "Is the research done yet?" |
| Get Deep Research Reportget_deep_research_report | Retrieve the final cited report for a completed deep legal research session. Returns markdown answer text with Westlaw citation links and citation metrics. | "Show me the full report with the citations." |
| Follow Up on Deep Researchfollow_up_deep_research | Start a follow-up legal research question against an existing completed deep research conversation. Use to clarify or extend an earlier research run on the same topic. | "How does Texas law differ on the same question?" |
As additional CoCounsel Legal capabilities are added to the connector, you will see new tools appear here.
Example prompts
These three prompts demonstrate the typical flow: start research, retrieve the cited report, then ask a follow-up — all in one Claude conversation.
Research how California courts have treated non-compete agreements for executive employees since 2020. Give me a concise memo.
What Claude does: Starts a concise deep research run scoped to California, tracks progress, and returns a cited memo summarizing recent California treatment of executive non-competes.
I asked you to research California non-competes earlier. Can you now retrieve the full report?
What Claude does: Retrieves the completed report for the saved conversation, rendering the markdown body with Westlaw citation links intact and appending citation metrics.
Follow up on that research: how does Texas law differ on executive non-competes for the same period?
What Claude does: Starts a follow-up research run against the same conversation, polls status, and returns the follow-up report comparing Texas treatment of executive non-competes to the prior California analysis.
What CoCounsel Legal in Claude is good for today — and what to use a different tool for
CoCounsel Legal in Claude currently covers deep legal research. For other CoCounsel Legal capabilities and other Westlaw workflows, use the matching tool.
Optimized for
- Initiating a legal research project with jurisdiction targeting (up to three US jurisdictions).
- Building a thorough, nuanced understanding of a legal issue, with arguments and counterarguments.
- Synthesizing case law, statutes, regulations, and administrative decisions into a cohesive narrative.
- Choosing between concise (several minutes) and expanded (20+ minute) research depths.
- Asking follow-up questions in the same conversation without restarting research.
Use a different tool for
- Drafting documents, summarizing files, or other CoCounsel work. Use CoCounsel directly.
- Retrieving a specific document. Use the search box on Westlaw.
- Getting an exhaustive list of results. Use Boolean search or Precision Research on Westlaw.
- Reviewing every case discussing a specific fact pattern. Use Precision Research on Westlaw.
- Identifying potential causes of action. Use Claims Explorer on Westlaw.
- Comparing how each jurisdiction treats an issue. Use AI Jurisdictional Surveys on Westlaw.
- Litigation analytics or judge, court, attorney, and firm profiles. Use Litigation Analytics on Westlaw.
- Non-US law. Use the country-specific version of Westlaw (UK, Canada, or Westlaw International).
Privacy and citations
Thomson Reuters legal research data accessed through this connector is proprietary and subject to licensing restrictions. Reports may include markdown citation links back to authoritative Thomson Reuters sources such as westlaw.com and 1.next.westlaw.com so you can verify each citation in Westlaw.
Do not redistribute connector responses outside your current Claude session in ways that would violate your CoCounsel Legal licensing terms. The full privacy policy describes what is collected, how it is used and stored, retention, and how to contact the owner.
Support
Support is provided by the Thomson Reuters CoCounsel support team. If a tool reports an error or a research run fails, the message Claude shows you will indicate whether to retry, sign in again, or contact support.
Email cocounselsupport@tr.com for help with access, entitlements, or connector issues.
Frequently asked questions
What subscription do I need to use this?
You need a CoCounsel Legal subscription with the MCP connector enabled for your account. Reach out to cocounselsupport@tr.com with questions about access or entitlements.
Will more CoCounsel Legal capabilities be added to the connector?
Yes. The CoCounsel Legal connector launches with deep legal research. Additional CoCounsel Legal capabilities will be added to the same connector over time, you'll see new tools become available without needing to reconnect or reinstall.
How long does a research run take?
A concise report typically takes several minutes. An expanded report runs deeper analysis across more sources and often takes 20 minutes or more. Claude will tell you when to expect results and can check progress along the way.
Can I ask follow-up questions on the same research?
Yes. Once a research run completes, you can ask follow-ups in the same Claude conversation. Claude will use the follow-up tool against the existing conversation so you do not have to restart research from scratch.