Claude Cowork cloud sessions are the default on every surface now, and the consequence is easy to miss: the session you started is not stored on the computer you started it from. It follows your Claude account. Close the laptop and it keeps working. Open your phone and it is there.
That is genuinely useful, and it is also narrower than it sounds. Two things follow your account. A third thing, the environment the work actually happens in, does not.
What follows you and what does not
Anthropic’s documentation is unusually clear on the first half. "Sessions in the cloud follow your account, so you can switch surfaces mid-task," and "the same sessions and files are available on desktop, web, and mobile." The July launch post put it more plainly still: close your laptop, it keeps going.
So your conversation follows you, and your files follow you, because both are saved to your Claude account rather than to a device.
Now the part almost nobody reports. The architecture overview states that "each session gets its own sandbox, created when the session starts and destroyed when it ends." The sandbox is a temporary isolated environment on Anthropic’s infrastructure holding "only session-scoped tokens that expire within hours."
That is a different kind of persistence from the one people assume. Your work is durable. The machine your work ran on is not. If you have installed packages, built a scratch directory or set up state inside a session, that lives inside a sandbox with a stated lifetime of exactly one session.
Claude Cowork cloud is not a choice you make
This is where our own earlier framing was wrong, and where most explanations of Cowork are wrong too.
Claude Cowork cloud and local execution both exist and both are documented, but as architecture rather than as a setting you pick. In Anthropic’s words, cloud means "the agent loop and code execution run on Anthropic’s servers," and local means they "run on the member’s device."
There is no documented per-task picker and no documented end-user toggle. The help center states flatly that sessions run in the cloud on every surface, and describes cloud as the beta default. The only documented control is an organization-level admin toggle, "Run Cowork in the cloud," which is on by default for Team plans and off by default for Enterprise, where it must be enabled and then granted to groups through custom roles.
One automatic routing rule is documented, and it is not your choice either: a scheduled task that requires local files or apps will only run locally.
So the honest description is not "here is how to choose." It is that the choice has largely been made for you, and on Enterprise it was made by your administrator.
What the desktop app is actually for now
If sessions run in the cloud everywhere, it is fair to ask what the desktop app still does. The answer is that it is the bridge to your own files, and the boundary is drawn precisely.
A cloud session can read and write files in folders you have connected, but only while the desktop app is open on that computer. The documentation is worth quoting exactly, because this single sentence is the whole trade: "If the app is closed, the session keeps running but can’t reach your local files."
Read that twice. The work does not stop when you close your laptop. It just goes blind to your disk. A session mid-way through processing a folder of documents will carry on doing whatever it can do without them.
Access is scoped rather than general. Only connected folders are reachable, and each local file or tool a session uses is checked against those permissions before it runs, over what Anthropic calls a brokered connection.
Two further details matter for anyone handling other people’s material. Files genuinely leave your machine: a changelog entry from July 21 updated the folder-access prompts specifically "to note that files Claude uses leave your device and are processed on Anthropic’s servers." And outputs come back as downloads rather than being written to your disk, since Cowork delivers finished outputs to the session where you preview and download them. If you assumed a cloud session was quietly saving into your folder, it is not.
Scheduled tasks are a different animal
Worth separating, because the naming invites confusion with the session portability above.
A scheduled task runs as its own Cowork session. It does not resume yours. Each firing is fresh, which means nothing you established in a previous conversation carries into it, and the instruction you schedule has to stand entirely on its own.
Scheduled tasks also run remotely, "so they run on their cadence even when your computer is asleep or the Claude Desktop app is closed," and they cannot be tied to a folder on your computer. They work with connectors and with files saved to your Claude account instead.
That contrasts with Dispatch, which is local: it "runs your tasks on your desktop, so your computer needs to be awake and the Claude Desktop app open while Claude works." Two features that both sound like sending work away, with opposite requirements.
The limits that are documented
Several, and they cluster around the network.
The sandbox cannot reach private, internal, link-local or cloud-metadata addresses. All traffic leaving it passes through a mandatory proxy with allow-listed destinations only, and no network access is the default for Enterprise organizations. One operational sharp edge: egress policy changes made mid-conversation will not take effect in that session, so a new conversation is required. And the egress permissions do not apply to web fetch, web search, or MCP connections including Claude in Chrome, which is a meaningful carve-out if you were treating the allow-list as your perimeter.
There is also a governance asymmetry that cuts against the local option. Local sessions store conversation history on the user’s machine and, per Anthropic, "cannot be centrally managed or exported by admins." Cloud sessions appear in compliance APIs. Cloud sessions are correspondingly invisible to endpoint detection tooling. Whichever way your organization leans, it is giving something up.
A few things are documented as unavailable outside the desktop app: live artifacts are desktop-only, and local file access, browser use and computer use from web or mobile all require the desktop app to be open. Computer use, the screen-control feature, is desktop-only and Pro and Max only, with Team and Enterprise excluded.
What this changes in practice
Three things, and the first is the one worth internalizing.
Treat the environment as disposable and the outputs as the deliverable. Because the sandbox is created and destroyed per session, anything you want to keep needs to end up in a file that lands in your account or on your disk. Setup work inside a session is not an investment.
Expect the local bridge to be the fragile part, not the Claude Cowork cloud session itself. In practice the connection to your own machine is the thing that comes and goes, while the session itself is stable. Work that can be done from connectors and account-saved files is more robust than work that depends on a folder on a laptop that might close.
Read the scheduled-task instruction as though the reader has amnesia, because it does. Every firing starts fresh.
For the wider picture of what Cowork is and who it is for, our introduction to Claude Cowork covers the product, and our look at Cowork on web and mobile covers the surfaces. The comparison with ChatGPT’s work surface covers the competitive picture, and our explainer on what AI agents are covers the underlying pattern.
Frequently Asked Questions
Where does a Claude Cowork session actually run?
In the cloud, on every surface, as the documented default. Anthropic describes two architectures: cloud, where the agent loop and code execution run on its servers, and local, where they run on your device. Web and mobile always use cloud. There is no published per-task picker, and the only documented control is an organization-level admin toggle called “Run Cowork in the cloud.”
Can I start a task on my laptop and finish it on my phone?
Yes, and this is well documented. Sessions in the cloud follow your account rather than your device, so you can switch surfaces mid-task, and the same sessions and files are available on desktop, web and mobile. What does not travel is access to your local files, which requires the desktop app to be open on the machine holding them.
Does my work keep running if I close my laptop?
Yes. The documentation states that if the desktop app is closed, the session keeps running but cannot reach your local files. So the work continues; it simply loses access to any connected folder on that machine until the app is open again. Scheduled tasks are unaffected because they run remotely by design.
What happens to files I create during a session?
Sessions and files are saved to your Claude account, which is why they appear across devices. The environment they were made in does not persist: each session gets its own sandbox, created when the session starts and destroyed when it ends. Treat anything inside the sandbox as temporary and make sure what matters ends up as a delivered file.
How long does a cloud session last before it expires?
Anthropic does not publish an inactivity timeout, a session-length cap or a storage quota. What is documented is that the sandbox is destroyed when the session ends, and that it holds only session-scoped tokens expiring within hours. Since the end of a session is not defined in the documentation, test this against your own workload rather than planning around an assumption.
Do my files leave my computer when a cloud session uses them?
Yes. A changelog entry from July 21, 2026 records that folder-access prompts were updated specifically to note that files Claude uses leave your device and are processed on Anthropic’s servers. Access is limited to folders you connect and each file or tool is permission-checked before use, but the processing happens on Anthropic’s infrastructure.
Does a scheduled task continue my existing conversation?
No. Each scheduled task runs as its own Cowork session, so every firing starts fresh with no memory of previous runs. Write the instruction so it stands alone. Scheduled tasks also run remotely and cannot be tied to a folder on your computer, working instead with connectors and files saved to your account.
Can my administrator control whether sessions run in the cloud?
On Team and Enterprise plans, yes. The documented setting is an organization-level toggle called “Run Cowork in the cloud,” on by default for Team and off by default for Enterprise, where it must be enabled and then granted to groups through custom roles. There is a governance trade-off either way: cloud sessions appear in compliance APIs, while local session history is stored on the user’s machine and cannot be centrally managed or exported.
