Microsoft Copilot Cowork: What Happened
On March 9, 2026, Microsoft announced Copilot Cowork, a new feature that transforms Microsoft 365 Copilot from a conversational assistant into an autonomous executor of complex tasks. The news spread across the tech world for one specific reason: Copilot Cowork is built in close collaboration with Anthropic and uses Claude as the AI model for reasoning.
This is the first time Microsoft has officially integrated an Anthropic model into a mass consumer/enterprise product like Microsoft 365. Until now, Copilot relied exclusively on OpenAI's GPT models. With Cowork, Microsoft opens the door to Claude Sonnet as an alternative for long-running agentic tasks.
For businesses using Microsoft 365, this is a game changer: the technology behind Claude AI — the same powering Anthropic's Claude Cowork — arrives directly inside Word, Excel, PowerPoint, Outlook and Teams.
How Copilot Cowork Works
Copilot Cowork brings multi-step task execution into Microsoft 365. This is no longer about asking Copilot to write an email or generate a table: with Cowork, you can delegate an entire workflow and the AI executes it autonomously, updating you on progress and asking for confirmation on critical steps.
A practical example: preparing a meeting with a client. With a single prompt, Cowork can assemble a PowerPoint presentation from internal data, gather relevant financial figures from Excel, send a briefing email to the team, and block a calendar slot for preparation. All in the background, while you work on something else.
The underlying technology is the so-called agentic harness — the same framework Anthropic uses for Claude Cowork. The model breaks down the request into sub-tasks, reasons about available tools (files, email, calendar, documents) and orchestrates them in sequence, maintaining context throughout the entire execution.
The Role of Anthropic and Claude AI
The collaboration between Microsoft and Anthropic is at the heart of this announcement. Copilot Cowork uses Anthropic's Claude model as the reasoning engine for agentic tasks. In practice, when Cowork needs to plan, decompose and coordinate a complex task, it is Claude doing the cognitive work.
This is significant for several reasons. First: Microsoft implicitly acknowledges that Claude is superior for long-running agentic tasks — an area where Opus 4.6 and Sonnet 4.6 excel thanks to agent teams and the 1 million token context window. Second: Microsoft makes Claude Sonnet models available to all M365 Copilot users — a historic shift away from GPT exclusivity.
For Anthropic, this is a massive validation. Claude moves from niche alternative to core component of a product used by hundreds of millions of enterprise users worldwide. For businesses, it means that investing in Claude expertise has double value: both for Anthropic's direct ecosystem and for the integration within Microsoft 365.
Work IQ: Microsoft's Competitive Advantage
The key differentiator of Copilot Cowork compared to Anthropic's Claude Cowork is Work IQ: the intelligence built on the enterprise data graph within Microsoft 365. Emails, files, documents, meetings, Teams chats — all of this feeds the context on which Cowork reasons.
While Anthropic's Claude Cowork runs locally on the user's device (macOS), Copilot Cowork operates in the cloud within the company's Microsoft 365 tenant. This means native access to enterprise data, built-in data protection, and no need to configure separate connections.
As Jared Spataro of Microsoft explained, the local approach has limitations in corporate environments — security, governance, and access to distributed data. Copilot Cowork's cloud approach solves these problems but introduces dependency on the M365 tenant. For businesses that live in the Microsoft ecosystem, this is a clear advantage. For those who prefer a more flexible, multi-platform approach, Claude Cowork direct remains the better choice.
Microsoft 365 E7: The New $99/User Plan
Alongside Copilot Cowork, Microsoft announced Microsoft 365 E7 — the most comprehensive enterprise plan ever offered, available from May 1, 2026 at $99 per user per month. The bundle includes Microsoft 365 E5 ($60), Microsoft 365 Copilot ($30), Agent 365 ($15), Microsoft Entra Suite and advanced security tools, with an $18 discount compared to purchasing separately.
For businesses, the math is straightforward. If you're already paying for E5 + Copilot ($90/user), adding $9 to get Cowork, Agent 365, and advanced security is a good deal. If you're on E3 or don't have Copilot yet, the jump to $99/user is significant and requires a clear business case.
It's worth comparing with Claude plans: Claude Team costs $30/user/month and includes Claude Code, Cowork and access to all models. Claude Enterprise has custom pricing but starts at around $60/user. For businesses not tied to the Microsoft ecosystem, Claude offers a competitive value proposition.
Copilot Cowork vs Claude Cowork: Comparison
The two platforms share the same underlying technology — Anthropic's agentic framework — but differ in deployment, ecosystem, and target audience.
Copilot Cowork runs in the M365 cloud, has native access to email/files/calendar via Work IQ, is integrated into Word/Excel/PowerPoint/Teams, and will be available in E7 from May 2026. It's the natural choice for businesses that live in Microsoft 365.
Claude Cowork runs locally on macOS, has access to local files and connected tools via MCP, works with all Claude models (including Opus 4.6), and is already available for Pro and Team plans. It's the right choice for those who want flexibility, local privacy, and access to the most powerful model (Opus).
The crucial difference is the model: Copilot Cowork uses Claude Sonnet for agentic tasks. Claude Cowork can also use Opus 4.6 — significantly more powerful for complex tasks. For advanced coding tasks, deep analysis, and strategic reasoning, Opus remains unmatched.
For many businesses, the answer won't be one or the other, but both: Copilot Cowork for daily work inside M365, and Claude direct for tasks that require the power of Opus and the flexibility of the Model Context Protocol.
What This Means for Businesses
Claude's entry into Microsoft 365 has three direct implications for businesses.
First: it normalizes Claude adoption. Many businesses already use Microsoft 365 and are evaluating Copilot. With Cowork, Claude is no longer a separate technology to discover and integrate — it's inside a tool they already know. This lowers the psychological barrier to adoption and legitimizes investments in Claude expertise.
Second: it creates a natural pathway. A business can start with Copilot Cowork inside M365, discover Claude's capabilities, and then extend adoption to Claude Enterprise or Claude API for more advanced use cases — automation with agent SDK, custom MCP integrations, financial modelling.
Third: it confirms the multi-model strategy. The most advanced businesses will use Claude inside M365 for daily work and Claude direct (via API or Enterprise) for specialized tasks. This hybrid architecture maximizes value while reducing costs. To understand how to structure it, see our guide on how to integrate Claude in your business.