# X402 Retry Safety Check

> X402 Retry Safety Check is a paid API for AI agents from api.delx.ai, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-20).

Checks whether retrying after an x402 challenge or delivery failure risks double settlement, given payment status, delivery status, and idempotency key presence.

## Facts

- Endpoint: POST https://api.delx.ai/api/v1/x402/x402-retry-safety-check?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-20
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-retry-safety-check-33755996
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_5qvze2XkStatTJR0ao4Qc

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability x402-retry-safety-check-33755996 -d '<json body>'
```

Example prompt: Before I retry this x402 agent call, check whether it's safe to do so — the payment has already been settled, the delivery was not received, and there is no idempotency key present.

## When to prefer this

Use this endpoint when your agent or payment orchestration layer needs a lightweight, stateless check before re-attempting an x402-protected request or agent delivery call, especially when you cannot reliably determine from your own state whether a prior payment settled. Prefer this over manual state inspection when working with caller-supplied challenge and result metadata that may be inconsistent.

## Known failure modes

- Missing required boolean fields returns validation error
- Ambiguous flag combinations may yield inconclusive rejection with mismatch reasons
- Network timeout returns no result — caller should not assume safe to retry

## How this service works

X402 Retry Safety Check: X402 Retry Safety Check checks whether retrying after challenge or delivery failure risks double settlement from bounded caller-supplied values without an external provider. Call X402 Retry Safety Check before paying for or accepting an x402 or agent delivery assembled from caller-supplied challenge and result metadata. Returns contract-specific checks, normalized evidence, mismatch reasons, and an explicit acceptance or rejection status for X402 Retry Safety Check as v…

## Output

Returns an explicit acceptance or rejection status indicating whether retry is safe, along with contract-specific checks, normalized evidence from the supplied flags, and mismatch reasons explaining why retry is or is not recommended.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "payment_settled": {
   "type": "boolean",
   "description": "Payment Settled supplied to X402 Retry Safety Check; used only for this bounded calculation and processed in memory without retention."
  },
  "delivery_received": {
   "type": "boolean",
   "description": "Delivery Received supplied to X402 Retry Safety Check; used only for this bounded calculation and processed in memory without retention."
  },
  "idempotency_key_present": {
   "type": "boolean",
   "description": "Idempotency Key Present supplied to X402 Retry Safety Check; used only for this bounded calculation and processed in memory without retention."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "result": {
   "safe_to_retry": true,
   "payment_settled": false,
   "delivery_received": false,
   "idempotency_key_present": true
  },
  "schema": "delx/util-x402-retry-safety-check/v1",
  "status": "pass",
  "evidence": {
   "retained": false,
   "input_sha256": "24c9a576b2e74386a2f828e8dd25d82245eaf5949169fae8a42b46b075a9b953",
   "external_calls": 0
  },
  "operation": "delivery_contract:x402_retry_safety_check"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-retry-safety-check-33755996/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.delx.ai](https://www.zero.xyz/host/api.delx.ai/llms.txt)