The Claude Code development team announced the change on its ClaudeDevs account on X on 6 November. The team said the change makes it easier to get a user’s own repository running in a cloud session. In a cloud session, Claude Code runs code on an Anthropic virtual machine rather than on the user’s own computer.

API keys are saved securely, so Claude never sees them, the team said. The post does not explain how Claude works out what is needed. Nor does it say whether the user approves the choices before they are saved.

What an environment stores

According to the Claude Code documentation, every cloud session runs in a cloud environment: a saved set of settings covering the network access level, environment variables and a setup script. The script runs before Claude starts work. The default environment has no variables or script, and the session’s network access allows only package registries and other hosts on the allowlist.

If the setup script finishes in roughly five minutes or less, Anthropic snapshots the filesystem, and later sessions start from that snapshot. The snapshot keeps installed packages and files but not running processes such as a database. If setup takes longer, the environment is not cached. The cache expires after roughly seven days and is also rebuilt when the setup script or allowed hosts change.

Keys go through a proxy

The documentation says API keys are stored securely as a network secret. Anthropic’s proxy adds the key to a request only after the request has left the session’s virtual machine, so the key does not appear in the session’s environment variables or files. A saved value cannot be viewed again.

The protection has limits. The proxy does not attach secrets to requests from the setup script or, for example, to requests to GitHub, the Anthropic API or public package registries. A key the proxy cannot attach stays in an environment variable, the documentation says, and anyone using the environment can read environment variables. A secret also grants access to its assigned hosts even if the environment’s network access level would not otherwise allow them.

The post says the update applies to Pro, Max and Ultra plans. Cloud sessions can be started at claude.ai/code, in the Claude mobile app, in the desktop app and in the terminal, the documentation says. Sessions count towards the plan’s usage limit, with no separate charge for the virtual machine. Users can edit environment settings from the environment selector on the claude.ai/code start screen. A network secret shows only its hosts and cannot be edited: changing it means deleting the secret and adding it again.