# x402-tools Null Score 21 Diagnostic

> x402-tools Null Score 21 Diagnostic is a paid API for AI agents from openclawproductions.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-11).

Returns a paid diagnostic JSON payload (SKU: nullscore21) via the x402 micropayment protocol, requiring $0.02 USDC per call through the OpenX402 facilitator.

## Facts

- Endpoint: GET https://openclawproductions.com/api/v1/nullscore21?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-11
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-tools-null-score-21-diagnostic-2d06f356
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_YZfXmcCiDnyuyGupVJQFB

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-tools-null-score-21-diagnostic-2d06f356
```

Example prompt: Run the nullscore21 x402 diagnostic against OpenX402 and show me the paid JSON response — I want to confirm the SKU, price, and title come back correctly after the $0.02 USDC payment goes through.

## When to prefer this

Use this endpoint specifically when you need to test or validate the x402 micropayment protocol flow — particularly eip3009-based payment gating — with a low-cost ($0.02 USDC) real paid SKU through the OpenX402 facilitator. Prefer this over mock or free endpoints when you need an end-to-end live payment confirmation.

## Known failure modes

- HTTP 402 returned with eip3009 extras when payment has not been submitted
- Facilitator mismatch: only OpenX402 is accepted; other facilitators will be rejected
- Malformed or missing properties parameter may result in an error response
- Network timeout or service unavailability at openclawproductions.com

## How this service works

Paid x402 diagnostics. Unpaid paid-SKU requests return HTTP 402 with eip3009 extras. Facilitator: OpenX402 only.

## Output

A JSON object containing the SKU name ('nullscore21'), a human-readable title ('Null Score 21'), the price ('$0.02'), and a diagnostic note clarifying it is an example paid shape. Unpaid requests receive HTTP 402 with eip3009 payment extras instead.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "properties": {
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "sku": "nullscore21",
  "note": "Example paid JSON shape. Not a live settle.",
  "price": "$0.02",
  "title": "Null Score 21"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-tools-null-score-21-diagnostic-2d06f356/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from openclawproductions.com](https://www.zero.xyz/host/openclawproductions.com/llms.txt)