Two products share the “Cowork” name right now, and that shared branding creates real confusion. Anthropic’s Claude Cowork and Microsoft’s Copilot Cowork both promise an AI that handles multi-step work autonomously, but they approach that promise from fundamentally different positions. Understanding the distinction matters before you commit workflows to either platform.
Desktop vs. Cloud: The Foundational Split
Claude Cowork runs as a native desktop application on macOS and Windows, with direct access to the local file system. That means you can point it at a folder of receipts, an Obsidian vault, or any locally synced cloud storage like Dropbox or Google Drive, and it works immediately. Microsoft 365 Copilot Cowork, by contrast, lives in the cloud. There is no local application with local file access. Files need to live in OneDrive before Cowork can touch them.
This distinction cuts both ways. The local model means Claude Cowork’s scheduled tasks only run when the machine is on and awake. Copilot Cowork’s scheduled tasks run in the cloud regardless of whether your laptop is open. If you travel frequently and want background automation to continue without leaving a desktop running, the cloud-native approach has a genuine advantage.
Data Access and Ecosystem Connectivity
Copilot Cowork connects directly to Microsoft 365 data through Microsoft Graph, which means your email, calendar, Teams chats, SharePoint sites, and OneDrive files are all immediately available without configuration. For organizations with strict compliance requirements, Purview auditing and existing governance controls extend naturally to Cowork activity, which makes it a much easier sell to security teams.
Claude Cowork can reach Microsoft 365 data through Model Context Protocol servers, but that requires configuration work, and the performance difference is noticeable. What Claude Cowork offers in return is broader MCP connectivity overall, including local MCP servers that Copilot Cowork currently cannot access at all. For professionals who depend on tools like Azure DevOps or custom data sources, the absence of MCP support in Copilot Cowork is a real constraint.
Context Windows and Model Access
Claude Cowork runs on the latest Claude models with context windows that can reach into the millions of tokens. Copilot Cowork operates with a significantly smaller context window, around 16,000 characters, which limits how much grounding information you can provide when defining complex tasks or custom skills. Microsoft does allow model selection within Copilot, and recent Claude releases have appeared there quickly, but the context ceiling remains a meaningful ceiling for sophisticated workflows.
Custom Skills: Where Copilot Cowork Gets Interesting
Copilot Cowork ships with a set of built-in skills covering email, calendar management, Word, Excel, PDF manipulation, and deep research. These are accessible through what appears to be a standard attachment button, but clicking through reveals a richer “add work context” menu with file, people, and meeting selectors alongside the skill library. It is easy to miss.
More interesting is the custom skill system. Skills are defined as Markdown files stored in a specific OneDrive folder structure: Documents, then Cowork, then Skills, with a subfolder per skill containing a skill.md file. This puts skill authoring within reach of anyone comfortable with Markdown, and those skills can be scheduled to run autonomously against your Microsoft 365 data. The built-in skill definitions are not exposed for inspection or modification, which limits how much you can learn from the existing implementations before writing your own.
Choosing the Right Tool
The honest answer is that these tools are not interchangeable, and the right choice depends on where your data lives and what your workflows require. Copilot Cowork fits naturally into organizations already standardized on Microsoft 365, particularly where compliance and governance are priorities. Claude Cowork remains the stronger option for anyone who needs local file access, broad MCP connectivity, or the head
