# ISO-8601 Duration String Validator

> ISO-8601 Duration String Validator is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-02).

Validates whether a given string is a conformant ISO-8601 duration (e.g. P1Y2M3DT4H5M6S) and returns true/false

## Facts

- Endpoint: POST https://agentshelf.syntexa.ch/v1/check-date-duration?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/iso-8601-duration-string-validator-0cb03b55
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_mBK0L9vBmfDsxGwobSM2P

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 iso-8601-duration-string-validator-0cb03b55 -d '<json body>'
```

Example prompt: Is the string 'P1Y2M3DT4H30M' a valid ISO-8601 duration? Just check the format, no parsing needed.

## When to prefer this

Use this endpoint when you need a fast, deterministic, server-side check that a string conforms to ISO-8601 duration format (e.g. P1Y, PT30M, P3DT4H5M6S) and don't want to implement or trust a local regex. Prefer the free sandbox POST /v1/sandbox/check-date-duration first to avoid the $0.002 charge during development or testing.

## Known failure modes

- Empty or missing value field returns an error (minLength:1 enforced)
- String exceeding 20,000 characters is rejected
- Malformed request body returns 4xx
- Payment not included or insufficient USDC triggers 402 response

## How this service works

Call when an agent needs whether a string is an ISO-8601 duration. Exact $0.002 USDC. Prefer unpaid POST /v1/sandbox/check-date-duration first.

## Output

Returns a boolean or conformance indicator stating whether the provided string is a valid ISO-8601 duration, with no network calls or LLM involved — a deterministic format check only.

## 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": [
    "PT1H2M"
   ],
   "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/iso-8601-duration-string-validator-0cb03b55/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)