Make the Free Server a Lease-Bound Executor Before Your Agent Double-Fires

Description and use

The pattern ensures external side-effects are performed at most once even if the process dies on a free server, by persisting lease and status in durable storage.

Problem

AI agents on disposable free-tier servers lose in-memory state on reboot, causing duplicate side-effects when a model call is retried after a crash.

Outcome

By persisting lease and side-effect status outside the disposable server, the pattern guarantees at-most-once execution of side-effects, eliminating duplicates caused by process restarts.

Workflow

• Place task in durable queue via orchestrator
• Free server acquires lease in external storage
• Write side-effect record as pending
• Call model endpoint (retryable)
• Apply external side-effect (e.g., create GitHub issue)
• Mark side-effect record as done
• If server dies, lease expires and orchestrator re-enqueues task
• New executor checks side-effect status: skip if done, finish if pending, start from step 3 if absent

Evidence

The executor writes a side-effect record with status pending to the same external store.

Source

If the server dies after applying effect, before marking done, the new executor sees pending and re-applies the effect.

Source