I’ve been spending a lot of time with Copilot Cowork over the past few days. And let me tell you — this one feels different. Not “nice incremental improvement” different. More like “this changes how I think about M365 Copilot” different.
Let me walk you through what Cowork actually is, how it works under the hood, and why I think it matters for everyone in the Microsoft ecosystem.
From Chat to Execution
Here’s the thing about M365 Copilot so far: it’s been great at generating content within a single app. Draft an email in Outlook. Summarize a meeting in Teams. Create a slide in PowerPoint. Solid, useful — but always one app, one task, one turn.
Copilot Cowork breaks that pattern entirely. Instead of asking Copilot to do one thing and getting a response, you describe an outcome — and Cowork builds a plan, coordinates across multiple apps, and executes step by step. In the background. While you do something else.
Think of it less like a chat assistant and more like delegating work to a capable colleague. You say “prepare a competitive analysis including a Word briefing doc, an Excel comparison sheet, and a customer-facing slide deck” — and Cowork actually does it. Creates the files. Saves them in OneDrive. Asks you to review before it sends anything.
That plan-to-action loop is what makes this fundamentally different from anything Copilot has done before.
The Anthropic Connection
Here’s where it gets technically interesting. Copilot Cowork is built in close collaboration with Anthropic. Specifically, it uses Claude’s agentic model and the same execution framework that powers Anthropic’s own Claude Cowork product.
Yes, you read that right. Microsoft — the company that poured billions into OpenAI — built its most ambitious Copilot feature on Anthropic’s brain. You can even choose between Claude models (Sonnet 4.6 or Opus 4.6) or just let Cowork pick automatically.
Microsoft calls this the “multi-model advantage.” Instead of being locked to a single AI provider, Copilot routes work to whatever model handles the job best. For Cowork’s long-running, multi-step tasks, that model happens to be Claude.
But here’s the crucial difference: while Claude Cowork runs locally on your desktop, Copilot Cowork runs in the cloud within your M365 tenant. That means it has access to Work IQ — Microsoft’s intelligence layer that draws signals from your Outlook emails, Teams chats, calendar events, SharePoint files, and more. Your AI coworker doesn’t just process files blindly. It understands the context of your work the same way you do.
What Cowork Can Actually Do
Cowork ships with 13 built-in skills: Word, Excel, PowerPoint, PDF, Email, Scheduling, Calendar Management, Meetings, Daily Briefing, Enterprise Search, Communications, Deep Research, and Adaptive Cards.
In practice, these skills combine in ways that feel genuinely useful.
Calendar triage. Tell Cowork to review your week. It flags conflicts, identifies low-value meetings, proposes changes — and once you approve, it actually declines, reschedules, and adds focus blocks to your calendar. I’ve used this multiple times already and it’s surprisingly good at identifying which meetings I don’t really need to attend.
Meeting prep end-to-end. Ask it to prepare you for a customer meeting. Cowork pulls relevant email threads, cross-references meeting notes, creates a briefing document, builds a slide deck, and schedules prep time on your calendar. One prompt. Multiple coordinated deliverables.
Document quality. The Word documents and PowerPoint presentations Cowork creates are noticeably better than what regular Copilot produces. Several early testers have noted the same thing — these Anthropic models are genuinely strong at document creation. The output looks professional, not like an AI first draft you need to rewrite from scratch.
Parallel task queuing. You don’t have to wait for one task to finish before starting the next. While Cowork is running your competitive analysis, you can already queue up “now draft me an email to the customer team with the key findings attached.” It handles the pipeline.
Custom Skills — This Is Where It Gets Really Powerful
Out of the box, Cowork is already useful. But the custom skills system is what turns it into something truly personal.
You create a SKILL.md file in your OneDrive under /Documents/Cowork/Skills/your-skill-name/ — a YAML frontmatter block with name and description, followed by Markdown instructions. If you’ve worked with GitHub Copilot agent skills or Claude skill files, the format is immediately familiar.
Cowork discovers your custom skills automatically at the start of each conversation. No admin configuration. No registration. You can have up to 20 custom skills, each up to 1 MB. And you can reference supplementary files in OneDrive or SharePoint from within a skill.
Here’s what makes this so powerful: the description field is what Cowork uses to decide whether to load a skill for a given conversation. So if you write a skill called weekly-status-report with a description like “Use this when creating weekly team status reports for leadership,” Cowork will automatically apply it whenever you ask for a status update — without you having to mention the skill by name.
I’ve already started building custom skills for my most repetitive workflows, and the time savings compound fast. Imagine baking your team’s document templates, communication standards, and reporting formats directly into the AI’s context. That’s what custom skills enable.
Cowork vs. Claude Cowork — Same Brain, Different Bodies
Since both products run on Claude under the hood, the natural question is: which one should you use?
The answer depends on where your work lives.
Claude Cowork runs locally on your desktop. It’s fantastic for individual knowledge workers who deal with local files — researchers, content creators, consultants working with documents on their machine. It requires no IT procurement, no tenant setup, no corporate cloud subscription. It’s fast, it’s capable, and at $20/month it’s accessible.
Copilot Cowork runs in the cloud within your M365 tenant. It has full access to your organizational context — emails, meetings, Teams messages, SharePoint files. Everything runs within Microsoft’s security, identity, and governance framework. For enterprise teams that live in M365 all day, the integration depth is unmatched.
The trade-offs are real on both sides. Claude Cowork can’t access cloud-based enterprise data. Copilot Cowork can’t interact with local files or applications outside M365. Choose based on where your critical work data actually lives.
For many of us in the Microsoft Partner ecosystem, the answer is clear: our data lives in M365, our customers’ data lives in M365, and an AI coworker that natively understands that entire context is exactly what we’ve been waiting for.
Prerequisites and Availability
Cowork is currently available through the Microsoft 365 Copilot Frontier program. Here’s what you need:
- A Microsoft 365 Copilot license
- Your tenant enrolled in the Frontier program (Copilot Settings in Admin Center)
- For EU/UK tenants: Anthropic models enabled as a sub-processor in M365 Admin Settings
- The Cowork Agent allocated to users from the Agent Store
It’s available in the browser at m365.cloud.microsoft and in the M365 Copilot desktop app for Windows and Mac. Mobile support isn’t there yet.
One important note: Cowork can only work with files in OneDrive and SharePoint. No local file access, no encrypted files, and attachments are capped at 200 MB.
My Take
I’ve tested a lot of Copilot features since the initial launch. Many were promising. Some were underwhelming. Cowork is the first feature where I genuinely changed how I work within the first few days.
The shift from “Copilot helps me write things” to “Copilot does the work while I focus on something else” is not incremental. It’s a different mental model. And the custom skills system gives you the lever to make it truly yours.
Is it perfect? No. It’s still in preview. Some tasks take longer than expected. The approval flow for sensitive actions (sending emails, posting in Teams) adds friction — but honestly, I want that friction. I don’t want an AI sending emails on my behalf without my explicit OK.
What I find most compelling is the trajectory. We went from single-turn chat, to in-app assistance, to a genuine execution layer that coordinates work across your entire M365 environment. That’s a meaningful evolution.
If you have M365 Copilot licenses and your admin can enable Frontier — give Cowork a serious try. Not a quick test. Spend a few days delegating real work to it. Build a custom skill or two. I think you’ll be surprised how quickly it becomes part of your daily routine.
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