# E2B 2.63.0 adds strict mode to sandbox pause()

published: 2026-11-04T17:05:41.092Z
topic: infrastructure
source: https://github.com/e2b-dev/E2B/releases/tag/e2b%402.63.0
url: https://aiagentnews.io/stories/e2b-2-63-0-adds-strict-mode-to-sandbox-pause

E2B has released version 2.63.0 of its e2b package, adding an optional strict flag to pause(). With strict mode on, a pause is refused while the sandbox's guest agent is not responding, and the sandbox keeps running.

The release, tagged e2b@2.63.0 on GitHub, lists one change under Minor Changes. The new strict option defaults to false. When it is set to true in TypeScript or True in Python, a pause fails with ServiceBusyError or ServiceBusyException if the guest agent does not respond.

Without strict mode, the API's default applies: the memory snapshot is still taken and the sandbox is marked. Sandbox info exposes that mark as envdUnresponsiveAtPause or envd_unresponsive_at_pause. Resuming a marked sandbox without onResume set to 'reboot' or on_resume set to "reboot" now throws GuestUnresponsiveError or GuestUnresponsiveException.

## Why it matters if you build agents

Code that pauses sandboxes can now choose strict mode to refuse a pause instead of saving a snapshot from an unresponsive guest, and should handle the new ServiceBusyError or ServiceBusyException.

Resume logic that does not pass a reboot option may now raise GuestUnresponsiveError on sandboxes marked at pause, so it should check the mark and handle that error.