Claude in a browser answers questions about uploaded files. Claude Cowork, in the Claude Desktop app, can create and edit files inside an approved project folder on the computer. Same model. Different place the work lives.
What Claude Cowork is
Cowork is a workspace in Claude Desktop. You choose a project or folder. Claude can read and write inside that scope. The output stays on the machine, in the files your team already opens in Excel, Word, or a deal folder.
That is the whole distinction. claude.ai is a conversation that can receive an attachment. Cowork is a conversation that can keep working on the attachment after the chat ends, because the file never left the folder.
Keep the scope deliberate. Give it the folder it needs, not the entire machine.
Files and local work
Most teams think they are having Claude do real work when they are still using it like a browser chatbot. The file goes up. A result comes down. Someone reopens it, fixes a formula, and sends it back in.
With Cowork, you create a project, drop the source files in, and ask Claude to build or edit the deliverable in place. The underwriting model, the memo, the checklist — it exists on disk. The next person on the team can open it without reconstructing the chat.
Cowork does not replace judgment. A person still owns the output. It replaces the shuttle between tabs.
How a team actually uses it
The useful version is not "everyone opens Cowork and sees what happens." It is one process, one folder, one person accountable for the result.
A working pattern:
- Pick a recurring deliverable with a known file shape: a model, a research memo, a first-pass review.
- Put the inputs the team already has into a project folder. Not licensed data you are not allowed to share. Files you own.
- Write or load a Skill so Claude follows the same steps every time, instead of improvising.
- Run the work in Cowork. Review the file. Keep the file.
If the process also needs a live system — CRM, property management, internal tools — that is MCP, not Cowork. Cowork is local files. MCP is reach. Skills tell Claude how; MCP is the door.
CRE example
Commercial real estate teams underwriting on claude.ai still bounce a spreadsheet through download and re-upload. In Cowork, the same request can create the model directly in the project folder and keep editing it there.
We walked through that setup, including how to create the project and run an office-condo underwriting request against local files, in Claude in CRE: Cowork. That note is part of the four-part CRE field guide, alongside Skills, Connectors, and Scheduled Tasks.
The CRE version is the same rule in a deal folder: Claude sits in the files the analyst already uses. Someone still reviews the model before it goes to a principal.
The real upgrade is not a better answer. It is a model that can continue working on the same approved files your team will actually use.