Anthropic has moved Claude Cowork’s execution environment entirely into the cloud. Felix Rieseberg, the engineer who leads Cowork and the Claude Code desktop app, published a post on October 5 explaining the difference between the old and new architecture, and Anthropic’s help center has since been updated: starting October 6, every new Cowork task created by Pro and Max users runs in the cloud, and the old “on your computer only” option has been removed.
The old setup’s weak point was the local VM
The previous version of Cowork was already “half cloud.” Model inference always ran on Anthropic’s servers, but the code Claude actually executed, and the commands it ran, lived in a virtual machine the desktop app pushed down onto the user’s own computer.
Rieseberg didn’t mince words: people disliked the disk space, power draw, and slowdown that local VM caused, and they disliked that closing the laptop lid stopped the work. For a product whose pitch is “hand off a task and go do something else,” that second complaint stung the most.
The new version puts both inference and the VM in the cloud, giving each session its own isolated sandbox that shares no state with any other. The desktop app’s role shrinks to that of a “local agent”: it only steps in to handle a single tool call when the cloud VM needs something that lives on the user’s own device, such as a specific file.
What actually changes for users
The help center lists three main changes:
- Tasks keep running in the background after the laptop is closed;
- Scheduled tasks no longer require the device to be online;
- Sessions and their output files stay in sync across desktop, web, and mobile.
Mobile and web can now also start and manage Cowork tasks. But anything that touches the local machine — reading local files, operating the browser, controlling the computer — still requires the desktop app to stay online for web and mobile to use it. Local file access also has a boundary: it’s limited to folders a user has already connected to Claude, the cloud session only receives a copy of the file, that copy is deleted when the session is deleted, and the original stays on the device.
The design essentially separates “compute” from “touch.” Computation, execution, and waiting all happen in the cloud; only the moment something actually needs to touch the user’s machine comes back to the local side. Rieseberg’s own summary is that this solves, in one move, using Cowork from a phone, letting tasks run without interruption, and no longer draining a laptop’s battery for a VM.
Cowork has changed shape several times over the past six months
Stringing together the milestones this outlet has covered, Cowork has consistently moved toward depending less on the user’s own computer. In April, Anthropic launched an enterprise-facing version of Cowork, pitched as letting Claude run long tasks for knowledge workers inside a controlled virtual machine. May brought the proactive assistant Orbit, along with a public beta of self-hosted sandboxes and MCP Tunnels, the latter letting enterprises run the execution environment on their own infrastructure. In August, Claude was built into the Chrome side panel, the desktop app gained its own built-in browser, and memory was connected to Cowork. By mid-September, chat and Cowork had merged into a single interface, so users no longer had to first decide which tab a task belonged in, and the update also added slide generation and collaborative documents, again rolled out to Pro and Max first.
This move to the cloud is the step in that sequence most noticeable to end users. Previous updates added capability; this one changes where the task actually runs.
What’s still unclear
The help documentation spells out the switchover date for Pro and Max, but for Team and Enterprise it only lists which platforms are supported — it doesn’t say whether the local-run option will also be removed for them.
For companies with compliance requirements, that’s not a small detail. Even if a file only enters a cloud session as a copy, that still means data has left an employee’s computer; IT teams that rely on endpoint security software watching local processes also have no visibility into what happens inside a cloud sandbox. Anthropic offered self-hosted sandboxes as an option back in May, but how that fits together with the new version’s default cloud mode isn’t addressed in any public material so far.
Cost is another variable. Keeping cloud sandboxes running continuously consumes Anthropic’s compute, and the longer a task runs — freed from being tied to whether a device is open or closed — the more resources it uses. Anthropic hasn’t said whether the new version changes how usage limits are calculated for Pro and Max; that will likely only become clear once users have been running it for a few weeks.
Sources: Felix Rieseberg’s explanation as relayed by Simon Willison’s blog, Anthropic’s Claude Help Center documentation on Cowork (checked for the scope of the cloud rollout, per-platform features, and local file access rules), CocoLoop, and TechCrunch (reporting on the merged chat-and-Cowork interface).