Sandboxes and previews

Each chat session gets a sandbox. It boots from a template, runs the project's services, and is reachable at its own preview subdomain behind a proxy that gates access. Sandboxes pause when idle and resume on demand, and they cost money while awake, which is why a workspace has a concurrent sandbox limit and why paused sandboxes are never woken just to answer a read.

Asking for a preview URL starts the sandbox if it is not running. That is the supported way to wake one.

A preview can be shared with somebody who has no Kosuke account. One link covers a project's main preview, one link covers a chat session's preview, and either is minted and revoked through the API as well as the interface. Opening the link resumes a paused sandbox the way a member's visit would, so the spend is the workspace's either way. The visitor gets the running app and nothing else in Kosuke, and cannot trigger an agentic deploy.