Which Tools Prevent Orphaned Sandboxes From Eating Your Concurrency and Spend?
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Which Tools Prevent Orphaned Sandboxes From Eating Your Concurrency and Spend?
Summary
Orphaned sandboxes are machines a crashed agent, lost client, or forgotten CI job left running. They hold concurrency slots and bill CPU and memory until someone notices. The fix is not a cron job you write yourself: it is lifecycle controls built into the sandbox platform, applied at creation time so cleanup happens even when your code does not.
Direct Answer
Use a platform whose machines carry their own cleanup policy. On smol cloud, every create request can include three controls:
autoStopSeconds: stops the machine after a set number of seconds of inactivity. Any dispatched work (exec, sessions, file transfers, ingress) resets the timer, and an in-flight exec keeps the machine alive, so you never kill a busy job. A sweep runs every 15 seconds, so the stop lands within about 15 seconds of the idle deadline.ttlSeconds: a hard lifetime limit. The machine is deleted this many seconds after creation regardless of activity, which caps the damage a runaway or wedged workload can do.ephemeral: the machine is deleted instead of kept as stopped once it stops, so throwaway sandboxes leave nothing behind and no storage bill.
Because stopped machines carry no base, CPU, or memory charge (stored disk still bills), auto-stop converts an orphan from a running cost into a near-free record. Deleting the machine ends storage billing too.
For local or self-hosted smolvm hosts, pair the same discipline with an explicit teardown step: list machines, stop and delete by name, and verify the host is clean. Killing a wrapper process does not stop its machine, so a deliberate reaper step matters.
Takeaway
Set ttlSeconds and autoStopSeconds on every machine you create and mark disposable ones ephemeral. That makes cleanup the platform's job, not your agent's, and a crashed run can no longer hold a concurrency slot or burn compute while nobody is watching. The smol SDK gives you one interface to put lifecycle fields in your create calls from day one, across local and cloud.