# X402 Delivery Schema Check

> X402 Delivery Schema Check is a paid API for AI agents from api.delx.ai, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-13).

Validates delivered x402/agent result objects against a caller-specified required field list, returning acceptance or rejection status with mismatch reasons and normalized evidence.

## Facts

- Endpoint: POST https://api.delx.ai/api/v1/x402/x402-delivery-schema-check
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-delivery-schema-check-3610a415
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_5KjPrS5rlPDU03R5FnQFd

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-delivery-schema-check-3610a415 -d '<json body>'
```

Example prompt: Before I pay for this x402 delivery, check the result object against my required fields list — ['invoice_id', 'amount', 'recipient', 'timestamp'] — and tell me if it passes or should be rejected.

## When to prefer this

Use this endpoint when you need a lightweight, in-memory, no-external-dependency schema check on an x402 or agent delivery result before committing to payment or downstream processing. Prefer this over custom validation logic when you want a standardized acceptance/rejection decision with explicit mismatch reasons, especially in agentic pipelines where result completeness must be gated before payment release.

## Known failure modes

- Result object exceeds 128 properties limit — request rejected
- Required fields array exceeds 256 items limit — request rejected
- Individual field name exceeds 8192 character limit — request rejected
- Malformed result object (not a valid JSON object) — validation error
- Empty required_fields array — may return acceptance trivially
- Payment of 0.001 USDC not fulfilled — 402 response returned

## How this service works

X402 Delivery Schema Check: X402 Delivery Schema Check checks delivered object fields against a caller-required field list from bounded caller-supplied values without an external provider. Call X402 Delivery Schema 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 Delivery Schema Check as versi…

## Output

Returns a structured response containing an explicit acceptance or rejection status for the delivered object, contract-specific field checks, normalized evidence of what was found, and detailed mismatch reasons for any fields that failed validation.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "result": {
   "type": "object",
   "description": "Result supplied to X402 Delivery Schema Check; used only for this bounded calculation and processed in memory without retention.",
   "maxProperties": 128,
   "additionalProperties": true
  },
  "required_fields": {
   "type": "array",
   "items": {
    "type": "string",
    "maxLength": 8192
   },
   "maxItems": 256,
   "description": "Required Fields supplied to X402 Delivery Schema Check; used only for this bounded calculation and processed in memory without retention."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "result": {
   "schema_valid": true,
   "missing_fields": []
  },
  "schema": "delx/util-x402-delivery-schema-check/v1",
  "status": "pass",
  "evidence": {
   "retained": false,
   "input_sha256": "5a2d2f997e6dd8109bb4a094caded4b79eb4c788696584b9ac0b919395398f9b",
   "external_calls": 0
  },
  "operation": "delivery_contract:x402_delivery_schema_check"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-delivery-schema-check-3610a415/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)