# ONE Engine Z-Score Calculator

> ONE Engine Z-Score Calculator is a paid API for AI agents from one-search.one-engine.workers.dev, paid per call via x402, $0.018/call, status unknown (last checked 2026-10-02).

Computes z-scores (standard scores) for an array of numeric values, with optional scaling and offsetting controls.

## Facts

- Endpoint: POST https://one-search.one-engine.workers.dev/v3/numeric/z-score/t9?utm_source=zero.xyz
- Price: $0.018/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/one-engine-z-score-calculator-f7f6417e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_XMv_anfX9VfpAKZ5Ugk1t

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 one-engine-z-score-calculator-f7f6417e -d '<json body>'
```

Example prompt: Can you calculate the z-scores for these values: [12, 45, 7, 89, 23, 56, 34, 78, 11, 67]? Round the results to 3 decimal places.

## When to prefer this

Choose this endpoint when you need a fast, cheap, pay-per-call z-score computation without standing up your own statistical infrastructure. Ideal for AI agents that occasionally need statistical normalization as part of a larger pipeline — the $0.018 USDC per-call pricing makes it economical for low-to-moderate volume. Prefer this over general-purpose math APIs when you specifically need z-score standardization with optional output clamping and scaling built in.

## Known failure modes

- Empty or missing 'values' array returns a validation error
- Array exceeds 1000 elements triggers a size limit error
- Non-finite numbers (NaN, Infinity) in the array cause computation failure
- All values identical (zero standard deviation) may return NaN or division-by-zero error
- Payment failure via x402 returns HTTP 402 before computation occurs

## How this service works

Low-cost pay-per-call utility APIs for autonomous agents using x402 on Base.

## Output

Returns a JSON object containing the z-scores for each input value, computed as (value - mean) / standard deviation. May include the computed mean, standard deviation, and the transformed array of standardized scores. Optional parameters allow clamping (min/max), controlling decimal precision (digits), and applying a scale factor and offset to the output scores.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "values"
 ],
 "properties": {
  "max": {
   "type": "number"
  },
  "min": {
   "type": "number"
  },
  "size": {
   "type": "integer"
  },
  "digits": {
   "type": "integer"
  },
  "factor": {
   "type": "number"
  },
  "offset": {
   "type": "number"
  },
  "values": {
   "type": "array",
   "description": "Finite numbers, maximum 1000"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object",
 "additionalProperties": true
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/one-engine-z-score-calculator-f7f6417e/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from one-search.one-engine.workers.dev](https://www.zero.xyz/host/one-search.one-engine.workers.dev/llms.txt)