# SIMULATION.md starters

Copy one, change the numbers, run it. Every tool is a mock and every number is a made-up example. A result describes the file, not reality, and is not a test, a safety assessment or advice. Terms: https://simulation.md/terms

- [refund-retry](https://simulation.md/worlds/refund-retry.md) (plan): Two ways to handle a refund that times out. Plan A retries after a short wait. Plan B waits for things to settle, checks the status, and retries only if nothing moved.
- [send-once](https://simulation.md/worlds/send-once.md) (plan): A notice that should reach someone exactly once. Plan A retries a plain send. Plan B sends with an idempotency key.
- [bulk-update](https://simulation.md/worlds/bulk-update.md) (plan): Updating 1,000 records. Plan A writes them all at once. Plan B writes in two batches and reads back before going on.
- [stale-read-decision](https://simulation.md/worlds/stale-read-decision.md) (plan): An agent acts on a value it read. Plan A acts on the first read. Plan B reads twice and acts only if they agree.
- [webhook-duplicates](https://simulation.md/worlds/webhook-duplicates.md) (plan): A webhook can arrive twice. Plan A applies every delivery. Plan B records the event id and applies it once.
- [ask-before-send](https://simulation.md/worlds/ask-before-send.md) (plan): Whether to wait for a person. Plan A asks and waits. Plan B sends and tells the person after. The measure weighs delay against a wrong send.
- [fanout-workers](https://simulation.md/worlds/fanout-workers.md) (world): 200 model calls under a rate limit and a spend cap. Change the workers and the limit.
- [warehouse-docks](https://simulation.md/worlds/warehouse-docks.md) (world): Trucks and unloading docks. Change the docks and the arrival rate.
- [support-desk](https://simulation.md/worlds/support-desk.md) (world): Tickets and people answering them. Change the staff and the handling time.
- [booking-race](https://simulation.md/worlds/booking-race.md) (world): Several agents try to book one slot by checking first, then booking.
- [approval-queue](https://simulation.md/worlds/approval-queue.md) (world): Requests waiting on a small group of approvers.