CoCounsel Legal connector for Claude: what it does, what access it gets, how to connect

Thomson Reuters runs a hosted CoCounsel Legal connector for Claude: legal research, review and drafting, with file uploads to CoCounsel. It does not cover tax research. Verified 21 Oct 2026.

This is a legal connector. None of the sources we checked describe Checkpoint or CoCounsel Tax content, so it is not a tax research tool. Thomson Reuters calls it a pilot that may change or be withdrawn without notice.

Claude connector · read, plus uploads to CoCounsel

Hosting: Remote HTTP, hosted by Thomson Reuters. The Claude directory lists the server as https://cocoagent-service.cocounsel.thomsonreuters.com/mcp. No local or open-source server.
Auth: Thomson Reuters sign-in window with your own account, authorised once (Thomson Reuters doesn't name the protocol); Claude may ask you to sign in again periodically.
Read / write: Reads Westlaw and Practical Law through CoCounsel. Uploads documents into a CoCounsel session and generates drafts there. No documented writes to any other system.
Works with: Claude.ai, Claude Desktop and Cowork sessions, per Thomson Reuters. Not documented for Claude Code or ChatGPT.
Plan requirement: An active Thomson Reuters account with a CoCounsel Legal package subscription; the Claude listing also asks for the next generation of CoCounsel. A Claude admin adds the connector for the organisation.
Last changed: May 2026: connector launched and listed in the Claude directory
Verification: Verified 21 Oct 2026 by theFinanceStack · confidence: high

What can an agent do with CoCounsel through MCP?

Claude hands a legal task to the CoCounsel agent and returns its cited result: research across up to 3 US jurisdictions, document review, drafting, chronologies and follow-up questions.

Tools

The current connector centres on one tool, Ask CoCounsel.

Tool	What it does
Ask CoCounsel	Sends your request and any uploaded files to CoCounsel.
Supporting tools	Start a session, upload and list files, and fetch a finished deliverable. Claude calls them for you.

Good to know

Thomson Reuters says research draws on Westlaw and Practical Law, with links back to the cited sources.
Expect each run to take minutes.
Thomson Reuters' older connector guide still describes an earlier set of 4 deep-research tools. The Claude directory and the newer guide show the agent tools above.

Can

Run legal research with jurisdiction targeting, up to 3 US jurisdictions per request
Review, summarise, compare or extract key terms from uploaded contracts and case files
Draft memos, correspondence or sections of legal documents inside CoCounsel
Build chronologies and extract structured data from a document set
Answer follow-up questions in the same conversation

Cannot

Read files attached with Claude's own paperclip button; files must go through the Upload File tool (per Thomson Reuters)
Run fully as intended in Cowork yet; Thomson Reuters plans more work in Q4 2026
Be used with another professional AI tool on Thomson Reuters content, including through an MCP (per Thomson Reuters' terms)
Change any accounting, tax or practice system: no such tools are documented

What access does it get?

Whatever your own Thomson Reuters account is entitled to in CoCounsel Legal; Thomson Reuters does not publish scope names.

Where	Scopes and permissions (as documented)	Admin requirement
CoCounsel Legal Claude connector (remote)	Not documented by the vendor. You sign in to Thomson Reuters and authorise the connector once. Thomson Reuters says a file uploaded through the connector stays available to CoCounsel for the rest of that chat; it points to its privacy policy for storage and retention and doesn't publish a retention period.	A Claude administrator adds CoCounsel Legal from the directory under Settings › Organization › Connectors (or the equivalent admin area for your plan) and makes it visible to the right groups. Each user needs a CoCounsel Legal package subscription; Thomson Reuters points access questions to your firm's administrator, your Westlaw Account Manager or cocounselsupport@thomsonreuters.com.

How do I connect it?

Add CoCounsel Legal from the Claude connector directory and sign in with Thomson Reuters; an admin enables it for the organisation first.

Admin, once: in Claude go to Settings › Organization › Connectors, add CoCounsel Legal from the directory, save, and check which groups can see it.
User: open Claude Desktop (or Claude.ai), go to Settings › Connectors, search for CoCounsel Legal and click Connect.
Complete the Thomson Reuters sign-in and authorise the connector.
In a chat, pick CoCounsel Legal from the connectors menu and name CoCounsel in your request. To share a document, ask Claude to use the Upload File tool.

Thomson Reuters writes the steps for Claude Desktop and lists Claude.ai and Cowork as supported. If new tools don't appear, use Refresh tools list on the connector page.

What should a finance team watch for?

Licensing limits on where Thomson Reuters content can go, pilot status, slow runs, and untrusted text in the documents you upload.

Thomson Reuters' terms prohibit using its content with another Professional AI Tool, which the Claude listing defines as a third-party legal, audit, tax, compliance or accounting AI service. In practice, don't enable CoCounsel in the same chat as accounting or tax connectors, and keep per-tool approval on for it: the listing says not to rely on "always allow" or "auto-approve" settings.
Per the Claude listing, Thomson Reuters content is for your organisation's ordinary internal business use only and may not be used as a knowledge base, index, embeddings store or retrieval source for any AI system. Don't drop outputs into Claude Projects or other retrieval stores, and check your licence before sharing output with clients.
Responses are licensed content: Thomson Reuters asks users not to redistribute them outside the current Claude session in ways their licence doesn't allow.
Pilot status: Thomson Reuters says it may modify, suspend or withdraw the connector at any time without notice.
Runs are slow: several minutes for concise research and 10 minutes or more for expanded research, per Thomson Reuters.
Deep research targets up to 3 US jurisdictions per request; other coverage follows your CoCounsel jurisdiction settings, per Thomson Reuters. Thomson Reuters doesn't publish file size or rate limits.
In its 12 May 2026 launch press release (see sources), Thomson Reuters said "Customer data is not used to train third-party models." The connector guide and help page don't repeat this; read its privacy policy and your Claude terms for retention.
Uploaded contracts and case files are untrusted input: an instruction hidden in a document could steer Claude's next steps, so review what it proposes to do with other tools.

How could finance teams and accounting firms use it?

It reviews documents and researches US law, and it has no tools that touch the books. That makes it a fit for contract and research questions that a lawyer or reviewer then checks.

Inside a company

Extract payment terms, renewal dates and termination clauses from a batch of uploaded vendor or customer contracts into a table for a person to check.
Compare two versions of a contract and list what changed before it goes to signature.
Build a dated chronology from the documents in a billing dispute to brief in-house or outside counsel.
Ask a research question across up to 3 US jurisdictions and take the cited report to counsel.

At an accounting firm

Summarise the key terms of a client's loan agreement or lease that the engagement team needs to read.
Pull defined terms and obligations from a set of client contracts into structured data for review.
Draft a first-pass memo on a legal question for a licensed professional to review and sign off.
Check access first: each person needs a CoCounsel Legal subscription, and outputs stay under Thomson Reuters licence terms.

Whatever the use, treat CoCounsel output as research for a qualified person to verify, and keep a person approving anything that changes your books or client records.

Want CoCounsel connected to Claude for your team?

We configure scoped connections and a review step before anything changes your books, for a fixed fee.

Book a 30-minute setup call

Change log

Date	Change	Source
2026-10-21	Re-verified: the directory connector now uses the CoCounsel agent tools (Ask CoCounsel, file upload, deliverables). The older guide still describes 4 deep-research tools	cocoagent-service.cocounsel.thomsonreuters.com/mcp/guide
2026-05-12	Thomson Reuters and Anthropic announce the MCP integration connecting Claude with CoCounsel Legal	www.thomsonreuters.com/en/press-releases/2026/may/thomson-re
2026-05	CoCounsel Legal added to the Claude connector directory as a Thomson Reuters pilot	claude.com/connectors/cocounsel-legal

FAQ

Is this official?

Yes. Thomson Reuters publishes the connector, and the Claude directory lists it as Anthropic verified.

Is it free?

Thomson Reuters doesn't list a separate price for the connector. It needs a CoCounsel Legal package subscription, and the pages checked don't publish that price.

Does it change data in CoCounsel?

Only inside CoCounsel: it starts sessions, makes files you upload available to CoCounsel for the rest of that chat and generates drafts. No tools write to accounting, tax or other systems.

Is my data used to train models?

Thomson Reuters said in its 12 May 2026 launch press release that customer data is not used to train third-party models; the connector guide and help page don't address training. Check its privacy policy and your AI provider's terms for retention and training.

Can my accountant use it on my behalf?

Thomson Reuters doesn't document this. Each user signs in with their own Thomson Reuters account and needs their own CoCounsel Legal subscription.

Something wrong or out of date? Tell us and we'll email you when it's fixed.

Sources

Verified by theFinanceStack, 21 Oct 2026. Vendor list on the CFO Software Market Map courtesy of Jason Staats; AI connectivity data by theFinanceStack. Not tax, compliance or financial advice.