idempotency

It copies a small Python program to the target over SSH, runs it, and deletes it. Once that is clear, the agentless claim, the performance characteristics and the idempotency requirement all stop being separate topics.

A billion-row backfill is a deployable, throttled, resumable job with checkpoints and verification gates. Ad-hoc scripts against prod are how it becomes an incident.

Wall-clock schedules meet daylight-saving transitions: spring forward deletes an hour of cron targets, fall back repeats one. Schedule in UTC, add idempotency keys, rehearse in staging.

Cron is the most-deployed scheduler on earth and the worst-behaved at scale. The scored content is everything crontab cannot do: exactly-once firing, thundering herds, and what happens when the scheduler itself dies.

Timeouts guarantee uncertainty, not failure: the first request may have succeeded after the client gave up. The idempotency key pattern is the industry answer; the scored details are storage, expiry and concurrency.

The difficult decisions are preserving offline intent and enforcing rules that span devices. Name the conflict classes and handle each deliberately rather than proposing a CRDT framework on instinct, because most of these conflicts have a domain answer that no merge algorithm can supply.

Trace a retry through the broker, database and external provider. The guarantee changes at each boundary, and a recorded intent does not prove a payment or email completed.

A disputed invoice needs a reproducible calculation. Retain raw usage events and versioned pricing so each line can be explained and corrected.

Cron fires at wall-clock times; a scheduler reasons about data intervals and blocked frontiers. The scored details are per-partition idempotency and catch-up semantics.