Quoting Felix Rieseberg
Anthropic's Felix Rieseberg described a change to how Cowork runs, according to a quote published by Simon Willison. In the "old" version of Cowork, model inference ran in the cloud while tool calls executed in an Anthropic-provided VM that was shipped to the user's computer. Rieseberg said the VM was added for capability, safety, and security reasons, and that it mapped in only the data a user explicitly added to a session.
Rieseberg said users liked what they could do with Claude but disliked the disk, battery, and performance cost of running the VM locally. He also said users disliked that closing a laptop meant work stopped.
In the "new" version, model inference and the VM both run in the cloud. Each session gets its own sandbox and does not share state with other sessions. When the VM needs something on the user's device, such as a file, the desktop app is responsible for that file access tool call.
Rieseberg said the change is intended to solve several reported problems, including using Cowork from a phone, keeping work running, and getting the same power without losing battery to the VM. The item was attributed to Felix Rieseberg of Anthropic, with a reference to a help page. It was tagged claude-cowork, anthropic, claude, generative-ai, ai, general-agents, and llms.
Based on reporting from the original publisher. Visit the source for full context and later updates.
Publisher excerpt
The "old" version of Cowork runs model inference in the cloud, executing tool calls in an Anthropic-provided VM we shipped to your computer. We added the VM for capability, safety, and security reasons - mapping in just the data you explicitly added to your session. People loved what they were able to do with Claude but didn't love the disk, battery, and performance cost of running the VM locally. Also, people didn't love that closing your laptop means the work stops. The "new" version of Cowork runs model inferenc