# AgentShelf Date String Validator

> AgentShelf Date String 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 given string is a real, well-formed YYYY-MM-DD date

## Facts

- Endpoint: POST https://agentshelf.syntexa.ch/v1/check-date-date?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/agentshelf-date-string-validator-04c7f6da
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_JrLJD8HCnIbabcNJzhjSk

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 agentshelf-date-string-validator-04c7f6da -d '<json body>'
```

Example prompt: Can you check whether the string '2024-02-29' is a real, valid YYYY-MM-DD date?

## When to prefer this

Use this endpoint when you need to confirm that a string both matches the YYYY-MM-DD format AND represents a real calendar date (e.g. correctly handles leap years, invalid month/day combos). The description notes a free sandbox alternative at POST /v1/sandbox/check-date-date should be tried first before incurring the $0.01 USDC charge. Prefer this paid endpoint only when the sandbox is unavailable or you need production reliability guarantees.

## Known failure modes

- Empty or missing value field returns an error
- String longer than 20000 characters rejected by schema
- Non-string input types may cause validation errors
- Network or payment failure returns 402 or 5xx
- Ambiguous date strings not in YYYY-MM-DD format may return false negatives

## How this service works

Call when an agent needs whether a string is a real YYYY-MM-DD date. Exact $0.01 USDC. Prefer unpaid POST /v1/sandbox/check-date-date first.

## Output

Returns a validation result indicating whether the input string represents a real, correctly formatted YYYY-MM-DD calendar date, including checks for valid months, days, and leap years.

## 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": [
    "2026-01-15"
   ],
   "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/agentshelf-date-string-validator-04c7f6da/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)