Thomson Reuters CoCounsel MCP Server

Thomson Reuters CoCounsel is a provider-hosted MCP connector that exposes CoCounsel Legal's research and drafting workflows to Claude. Announced May 12, 2026 as part of Anthropic's broader Claude for Legal launch, the integration lets a lawyer working inside Claude pass legal tasks directly to CoCounsel Legal, and lets a user inside CoCounsel route queries back through Claude for broader reasoning. Thomson Reuters CTO Joel Hron has clarified that the connector surfaces CoCounsel capabilities inside Claude but does not replace the standalone CoCounsel Legal platform.

The connector is grounded in Thomson Reuters' authoritative legal content: a corpus of roughly 1.9 billion Westlaw and Practical Law documents, 1.4 billion KeyCite validity signals, and a patent-pending citation ledger that makes every source traceable in one click. Typical tasks the integration is positioned for include Westlaw-grade case law research, Practical Law guidance lookup, KeyCite validity checking, contract review, deposition prep, and brief drafting with validated citations.

The next generation of CoCounsel Legal is rebuilt on Anthropic's Claude Agent SDK, shifting from fixed workflows to an agent that plans, selects tools, retrieves authoritative content, and adapts mid-workflow. The connector is currently in beta, with general availability for the next-generation CoCounsel Legal expected in summer 2026. A paid CoCounsel subscription is required to use it.

Tools

CoCounsel is a directory connector hosted by Thomson Reuters. There is no package to install and no public GitHub repo. You enable it from within Claude.

Prerequisites

• A paid CoCounsel Legal subscription from Thomson Reuters
• A Claude account (Pro, Max, Team, or Enterprise). On Team and Enterprise, an Owner or Primary Owner must enable directory connectors for the organization before individual users can authenticate.

Enable the connector in Claude

• In a Claude chat, click the + button in the lower left, or type / to open the menu and choose Connectors.
• In the Connectors modal, find CoCounsel Legal (Thomson Reuters) under the Legal category.
• Click Connect and complete the OAuth sign in with your Thomson Reuters / CoCounsel credentials.
• Once authenticated, Claude can call CoCounsel tools during chats. You can toggle the connector on or off per conversation.

Status

The integration is in beta as of May 2026. General availability for the next-generation CoCounsel Legal, rebuilt on the Claude Agent SDK, is expected summer 2026. Specific tool names, scopes, and rate limits have not been published in public documentation; refer to Thomson Reuters CoCounsel documentation and the Claude Connectors Directory for the current list.

• Ask Claude a legal question and have CoCounsel run Westlaw-grade research, returning a memo with full case and statute citations.
• Pull Practical Law guidance and standard clauses for a transaction directly into a Claude drafting session.
• Validate every citation in a draft brief against KeyCite before filing, surfacing negative treatment and overruled authority.
• Hand a contract review or deposition prep matter from Claude to CoCounsel and pull the cited, traceable work product back into the chat.
• Triage an inbound matter in Claude, then route the parts that need fiduciary-grade output (research memos, briefs) to CoCounsel for citation-ledger-backed drafting.

• "Use CoCounsel to find Second Circuit cases from the last five years on enforceability of non-competes for software engineers, and summarize the holdings with citations."
• "Pull the Practical Law standard document for a mutual NDA governed by Delaware law and adapt it for a SaaS vendor relationship."
• "Run KeyCite on every case cited in this draft motion and flag any that are no longer good law."
• "Hand this 40 page deposition transcript to CoCounsel, identify the strongest impeachment opportunities, and return a cited summary."
• "Research the elements of a Section 10(b) securities fraud claim under recent Ninth Circuit law using Westlaw, and draft the legal standard section of a brief with citations."

• Official integration built jointly by Thomson Reuters and Anthropic, not a community fork.
• Grounded in authoritative content: Westlaw, Practical Law, and KeyCite, with a citation ledger for source traceability.
• Bidirectional with CoCounsel Legal so work moves between Claude and CoCounsel without switching tools.
• Available as a one click directory connector in Claude with no self-hosting required.

• Requires a paid Thomson Reuters CoCounsel subscription, which is enterprise-priced.
• In beta as of May 2026; specific tool names, rate limits, and OAuth scopes are not publicly documented.
• Surfaces CoCounsel capabilities inside Claude but does not replace the standalone CoCounsel Legal platform, per Thomson Reuters CTO Joel Hron.

• Free Law Project / CourtListener MCP: Open access US case law and PACER data, announced alongside the CoCounsel integration.
• Harvey Claude connector for legal AI workflows at large firms.
• Midpage and Descrybe Claude connectors for AI assisted legal research on public sources.