003: Boxes live until their thread ends or they are released

Status: accepted, 30 September 2026.

Context

Agents work asynchronously. A thread may sit idle for hours while you review its work, then carry on. If a box expires or is reclaimed for idleness, the agent loses its running apps, its build caches and your place in the desktop.

Decision

• A box is released only when:
  • you or the agent release it;
  • its thread is archived or deleted.
• There is no maximum age and no idle timeout.
• The only limit is the provider’s capacity. A limit on boxes per thread is a setting, off by default.
• Stopping and starting a box, where a backend supports it, is an action you or the agent take. It never happens automatically.

Consequences

• Capacity is the real constraint. Backends report it before acquiring, and the message says what is full and what to release.
• The panel shows every box a thread holds, so forgotten boxes are visible.
• A crash must never lose track of a box. Ownership is recorded with the provider where possible (for example tags), and a sweep releases the boxes of ended threads (architecture).