MCP Connectors for Legal: Harvey, Westlaw, and Claude (2026)

The Short Answer

Yes, there is an official Harvey connector for Claude, and yes, there is a Thomson Reuters connector that reaches Westlaw content, both shipped in May 2026 as part of Anthropic's Claude for Legal launch, which lists more than 20 legal connectors in total. But "connector" oversells what most of them do today. The Harvey connector lets Claude ask Harvey questions; it does not let Claude run Harvey. The Thomson Reuters connector runs deep research over Westlaw and Practical Law content but does not expose KeyCite. Most of the legal connectors in the toolkit are read-only and scoped to a few tools, and many are gated to Team and Enterprise workspaces through Claude's Cowork agent. Below is what MCP is, which legal platforms have official connectors as of September 2026, what each one actually does, and what to do when the system you need has none.

What MCP Is, in One Paragraph

The Model Context Protocol (MCP) is an open standard, originally published by Anthropic and now adopted by OpenAI, Google, and Microsoft among others, that defines how an AI assistant talks to an outside system. A vendor runs an "MCP server" that exposes a small set of named tools (search this, fetch that, list these), and an assistant like Claude can call those tools mid-conversation, with the user's own login and permissions. Think of it as a standard plug: instead of every legal platform writing a bespoke Claude integration and a bespoke ChatGPT integration, it writes one MCP server and any compliant assistant can connect. A "connector" in Claude's directory is simply an MCP server Anthropic has listed and made one-click to enable. Our Claude for Legal plugin setup guide covers the practical side of turning them on.

Which Legal Platforms Have Official Claude Connectors (September 2026)

Anthropic's Claude for Legal announcement (May 12, 2026) and the LawSites coverage of it list the following connectors. We report them here as factual entries; inclusion is not a recommendation, and most solo and small firms will use only a few of them.

• Legal research and legal AI: Thomson Reuters (CoCounsel Legal, which reaches Westlaw and Practical Law content), Harvey, Midpage, Trellis, Legal Data Hunter, Solve Intelligence (patent work).
• E-discovery: Relativity, Everlaw, Consilio.
• Contracts and signatures: Ironclad, DocuSign (including DocuSign CLM), Definely.
• Document management and deal rooms: iManage, NetDocuments, Box, Datasite.
• Expert networks: Lawve AI, The L Suite (Lloyd and TopCounsel).
• Public service and access to justice: CourtListener (Free Law Project), Courtroom5, Descrybe, BoardWise.

Two things are notably absent. LexisNexis has no listed Claude connector as of this writing, so Lexis+ AI and Shepard's are not reachable from a Claude conversation. And there is no connector for Clio or any other practice-management or billing system in the toolkit; Claude for Legal does not touch time entries or invoices. Anthropic's open-source CONNECTORS.md file also maintains a "wanted" list of integrations it does not yet have, including USPTO, PACER write access and state e-filing, eCFR and other regulatory primary sources, and a fuller Thomson Reuters Westlaw connector for all plugins.

The Harvey Connector: What It Actually Does

The queries that bring most readers here are "harvey mcp," "harvey plugin," and "harvey claude connector," so here is the precise answer. Harvey publishes an MCP server, documented at developers.harvey.ai, that works with Claude (web and desktop), Google Gemini, and Microsoft 365 Copilot. It exposes a handful of tools: ask Harvey a general legal question, ask a question about documents in one of your Harvey Vault projects, run a question against a selected knowledge source, and list which Vaults and knowledge sources you can see. Authentication is per user over OAuth, and the server can only reach data the authenticated user already has permission to view in Harvey. Tool calls are stateless; Harvey keeps no conversation history between requests.

What that means in practice: the Harvey connector is a question-answering bridge, not a control surface. Claude can pull a Harvey answer, with Harvey's citations, into a broader workflow it is running (say, a Cowork agent assembling a diligence memo that also reads a data room). It cannot create Vault projects, upload documents into Harvey, run Harvey workflows, or edit anything on the Harvey side through the documented tools. It also presupposes a Harvey subscription and an admin who has enabled MCP for the organization, which puts it well outside the reach of most solo and small firms; our Harvey pricing analysis explains why. For firms that do have Harvey, the connector is a genuinely useful way to let Claude's agents consult Harvey's research layer, and Harvey's decision to join Claude's ecosystem rather than stay outside it is the more interesting story; we cover the relationship in does Harvey use Claude and the broader comparison in Claude vs Harvey.

The Thomson Reuters Connector: Westlaw Content, Not KeyCite

Thomson Reuters' CoCounsel Legal MCP connector guide is unusually candid about scope, and lawyers should read it before assuming "Westlaw in Claude." As of September 2026 the connector requires an active CoCounsel Legal subscription with MCP enabled, supports Claude Desktop, and exposes one capability: deep legal research. Its four tools start a research session targeting up to three U.S. jurisdictions, check progress, retrieve a cited report in markdown with Westlaw links, and ask follow-up questions against the finished research. Runs take several minutes for a concise report and twenty minutes or more for an expanded one. The guide states that the connector is not optimized for drafting, for retrieving a specific known document, for exhaustive result lists, or for non-U.S. law, and that KeyCite is not currently exposed, with more capabilities promised over time.

The KeyCite point deserves emphasis. A connector that runs research over Westlaw content but does not surface citator treatment cannot tell you whether a case is still good law, which is why our post on whether Claude can check good law still ends at "go to the citator." The connector shortens research; it does not replace the citator run.

The Read-Only, Partial-Scope Reality

The Harvey and Thomson Reuters examples are typical rather than exceptional. In the open-source toolkit's connector table, most legal entries are marked read-only: CourtListener, Descrybe, Definely, Solve Intelligence, TopCounsel, Ironclad, Everlaw, Trellis, Courtroom5, and Lawve AI, among others. Read/write access appears mainly on the general-purpose systems (Slack, Google Drive, Box) and a few legal ones (iManage, DocuSign). Anthropic's own guidance for connector authors explains why: it asks for read-heavy tools, explicit client-side confirmation on any write, provenance in every result (source, retrieval date, citation-ready identifiers), and resistance to instruction-like content in returned data. For a law firm that is the right design. A connector that can silently write into a document-management system or an e-signature workflow is a confidentiality and malpractice surface, and read-only scoping is how the ecosystem keeps the lawyer in control.

The other constraint is plan gating. Per Anthropic's announcement, the commercial connectors (Harvey, Thomson Reuters, the e-discovery and contract platforms) are available to Team and Enterprise workspaces through Cowork, where an admin enables them; the public-service connectors (CourtListener, Courtroom5, Descrybe, BoardWise) are available to individual Claude users. A solo on Claude Pro can therefore connect CourtListener today for free, per the Free Law Project's announcement, and get case law, PACER dockets, citation networks, and citation-verification tools; the same solo cannot use the Harvey connector without a Harvey contract and a Team-or-above workspace. In our experience this is the single most common misunderstanding about Claude for Legal: the plugins are free and open source on any paid plan, but several of the headline connectors require both a paid third-party subscription and a business-tier Claude workspace.

Custom Connectors: The Path When Nothing Exists

If the system your firm lives in is not on the list (LexisNexis, Clio, your state's e-filing portal, a county records site, a practice-specific database), the answer is a custom MCP server, and it is more attainable than it sounds. Two routes:

• Vendor-published servers not yet in the directory. Claude supports adding a remote MCP server by URL under Settings, subject to workspace policy. If your vendor has shipped an MCP endpoint but has not been listed by Anthropic, you can often connect it directly; ask the vendor for its MCP documentation before assuming there is none.
• Build your own. An MCP server is a small web service that wraps an API you already have access to, exposing a few read-only tools. Anthropic's connector guidelines linked above are a good specification: OAuth or API-key auth, search/fetch/list tools, provenance on every result, no writes without confirmation. A developer can stand one up against most legal APIs in days, and Anthropic's open-source repository accepts submissions that pass its retrieval-quality and injection-resistance checks, so a connector your firm builds for a common system may end up in the default toolkit.

Either way, apply the same discipline you would to any vendor: know what the connector can read, confirm it cannot write without your say-so, and run it on a business-tier workspace where the data terms are contractual. Our reusable Claude Project workflow shows how to fold a connector into a matter workspace once it is enabled.