# Retries and idempotency

Agents crash, time out and try again. Retrying is always safe.

## Idempotency-Key

Every create and fork carries an `Idempotency-Key` of 8 to 200 characters, one per task. Send the same key and body again and you get the same sandbox back, with `Idempotent-Replayed: true`.

| Answer | Meaning |
| --- | --- |
| `201` | Created and running. |
| `200` | This key was answered before. Same sandbox. |
| `202` | Asked for, not yet confirmed. Wait 10 seconds and resend. |
| `409 idempotency_conflict` | Key reused with a different body. Use a new key. |
| `422 create_failed` | Failed for good. Use a new key and try once more. |

## Uncertain operations

The operation is recorded before the host is touched. If a create times out halfway, it is marked uncertain. Send the same key again, or call `POST /v1/reconcile`, and the machine that already exists is adopted. A second one is never created.

## Proxy errors

A `502`, `504`, `52x` or any error without a `code` came from a proxy, not agental. Your request may still be running. Wait 10 seconds. Repeat a create with the same key. For anything else, `GET` the sandbox first.

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Every page of these docs as Markdown: [llms.txt](https://agental.io/llms.txt)