# Discover Card Luhn Validator

> Discover Card Luhn Validator is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-02).

Validates whether a card number passes the Luhn algorithm and matches Discover card BIN patterns

## Facts

- Endpoint: POST https://agentshelf.syntexa.ch/v1/check-card-discover?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/discover-card-luhn-validator-b5de62a7
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_W9Gt_71NWUdhpY2TD0fAz

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 discover-card-luhn-validator-b5de62a7 -d '<json body>'
```

Example prompt: Can you check if the card number 6011000990139424 is a valid Discover card — does it pass the Luhn check and match Discover's format?

## When to prefer this

Use this endpoint when you need to confirm a card number is both checksummed-valid (Luhn) and belongs specifically to the Discover network, with zero storage of sensitive data. Prefer the free sandbox endpoint POST /v1/sandbox/check-card-discover first if available. Choose this over generic Luhn-only checkers when Discover network identification is also required.

## Known failure modes

- Missing or empty value field returns validation error
- Value exceeding 20000 characters rejected
- Malformed JSON body returns 400-level error
- Network or server error returns 5xx response
- Payment of $0.01 USDC required; missing x402 payment header results in 402 Payment Required

## How this service works

Call when an agent needs whether a number passes Luhn and matches discover. Nothing is stored. Exact $0.01 USDC. Prefer unpaid POST /v1/sandbox/check-card-discover first.

## Output

Returns whether the submitted card number passes the Luhn algorithm checksum and whether it matches Discover card BIN prefix patterns, with no data retained after the call.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "data": {
   "description": "JSON value for schema-check SKUs. Omit it on string checks such as email or IBAN."
  },
  "value": {
   "type": "string",
   "examples": [
    "411111"
   ],
   "maxLength": 20000,
   "minLength": 1,
   "description": "Value to check. The route description names the format: email, phone, IBAN, postal code, VAT, national id, or similar."
  },
  "schema": {
   "description": "JSON Schema document for schema-check SKUs. Omit it on string checks."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/discover-card-luhn-validator-b5de62a7/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agentshelf.syntexa.ch](https://www.zero.xyz/host/agentshelf.syntexa.ch/llms.txt)