# Delx Set Union

> Delx Set Union is a paid API for AI agents from api.delx.ai, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).

Returns the order-preserving union of two JSON arrays, with a count of the resulting items.

## Facts

- Endpoint: POST https://api.delx.ai/api/v1/x402/set-union
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/delx-set-union-174ffcff
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_QXU7nDGGR8grnhn9UGAKc

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 delx-set-union-174ffcff -d '<json body>'
```

Example prompt: Merge these two allowlists into a single deduplicated, order-preserving union: ["read", "write", "delete"] and ["write", "execute", "read"].

## When to prefer this

Choose this endpoint when you need a fast, stateless, order-preserving set union of two JSON arrays — especially for merging allowlists, permission sets, or tag lists in an agent workflow — and you don't need a full general-purpose data processing pipeline. Ideal for lightweight agentic set math where no external data, authentication, or side effects are needed.

## Known failure modes

- Non-array inputs for a or b will likely cause a validation error
- Missing required fields (a or b) may return a 400 error
- Payment failure via x402 will prevent the response from being returned
- Very large arrays may increase latency or hit size limits

## How this service works

Set union of two lists (order-preserving). Call when you merge agent allowlists. Returns union items and count for $0.001 USDC via x402 on Base. No network, no keys, no retention; first-party local JSON only. Results are advisory; the caller owns budgets, auth, and production controls.

## Output

Returns the order-preserving union of the two input arrays (items from array A first, then any items from array B not already in A), along with the total count of items in the resulting union.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "a": {
   "type": "array",
   "description": "Input field: a."
  },
  "b": {
   "type": "array",
   "description": "Input field: b."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "count": 3,
  "items": [
   1,
   2,
   3
  ],
  "schema": "delx/util-set-union/v1"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/delx-set-union-174ffcff/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.delx.ai](https://www.zero.xyz/host/api.delx.ai/llms.txt)