# ONE Engine Array Union

> ONE Engine Array Union is a paid API for AI agents from one-search.one-engine.workers.dev, paid per call via x402, $0.0011/call, status unknown (last checked 2026-10-02).

Computes the union of two arrays, returning all unique values that appear in either array.

## Facts

- Endpoint: POST https://one-search.one-engine.workers.dev/v1/array/union?utm_source=zero.xyz
- Price: $0.0011/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-array-union-a69d3eec
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_rPFk6K313GWToDphbEAC8

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-array-union-a69d3eec -d '<json body>'
```

Example prompt: Compute the union of these two arrays for me: [1, 2, 3, 4] and [3, 4, 5, 6] — I just need all the unique values combined.

## When to prefer this

Choose this endpoint when you need a quick, cheap, pay-per-call set union operation on two arbitrary arrays without spinning up your own logic. It is ideal for autonomous agents that need lightweight, stateless array math on Base-settled micropayments with no server overhead.

## Known failure modes

- Missing or malformed array inputs return an error
- Non-array values for 'a' or 'b' fields may cause validation failures
- Payment failure via x402 prevents execution
- Empty arrays on both sides return count 0 and empty values array

## How this service works

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

## Output

A JSON object containing the count of unique elements and an array of all values (deduplicated) that appear in either input array A or array B, e.g. {"count": 3, "values": [1, 2, 3]}.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "a": {
   "type": "array"
  },
  "b": {
   "type": "array"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "count": 3,
  "values": [
   1,
   2,
   3
  ]
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/one-engine-array-union-a69d3eec/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)