Anthropic Pushes Claude Cowork Into Big Law With 20+ Integrations and an M365 Agent

Anthropic is going hard at the legal market, rolling out more than 20 new Claude Cowork integrations and 12 role-specific AI plugins built around the way law firms and in-house teams actually work — contract review, redlining, M&A due diligence, employment handbook drafting, and litigation matter management. The push, unveiled around an Anthropic webinar that drew more than 20,000 legal professionals on May 15, is the company's largest vertical-specific Cowork expansion to date and lands legal at the top of the power-user leaderboard inside its agentic platform.

The headline integration is a cross-app Microsoft 365 agent. Claude now embeds across Microsoft 365 — Word, Outlook, Excel, and PowerPoint — as a single context-carrying agent, so a lawyer can move from drafting a brief to summarizing a discovery email thread to building a deal model without losing state. That matters because the workflow context, not raw model quality, has historically been the bottleneck for AI in legal: every app handoff was a fresh prompt and a fresh chance to hallucinate.

Anthropic is also leaning hard on grounding. Claude Cowork now connects through plugins to Westlaw, CourtListener, and iManage repositories, anchoring outputs in verified primary sources rather than free-form generation. "In litigation, an authoritative-sounding hallucination is worse than no answer," Eve's CEO told Fortune — a line that captures both the technical bet and the liability calculus driving the design.

The early adopter list is unusually heavyweight: Freshfields, Quinn Emanuel Urquhart & Sullivan, Holland & Knight, and Crosby Legal are all running Claude on active matters. Quinn Emanuel partner Christopher Kercher, describing how the firm built its litigation platform, said the unlock was philosophical: "The breakthrough was treating Claude like a member of the case team." Anthropic is also citing a 90.9% score for Claude Opus 4.7 on Harvey's BigLaw Bench, the closest thing the industry has to a frontier-model legal benchmark.

The strategic read is that Anthropic is doing for legal what it just did for finance with the PwC Office of the CFO deal: pick a high-margin, regulated, document-heavy function, build the connectors and plugins that match the workflow, and stake out the category before OpenAI or Microsoft's own Copilot Legal Agent can lock it down. Combined with the Big Law adopter list and the M365 cross-app agent, Cowork for legal is positioned as one of the most concrete agentic deployments in the enterprise market right now.