# ONE Engine Query Builder

> ONE Engine Query Builder is a paid API for AI agents from one-search.one-engine.workers.dev, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-02).

Builds a structured search query string from a value object for use with the ONE Engine search API.

## Facts

- Endpoint: POST https://one-search.one-engine.workers.dev/v1/query/build?utm_source=zero.xyz
- Price: $0.001/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-query-builder-cc1e3220
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_9-FjJMph7cVr5wN_KMT5x

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-query-builder-cc1e3220 -d '<json body>'
```

Example prompt: Build me a ONE Engine search query from these parameters: search for 'autonomous agents x402' on page 2.

## When to prefer this

Use this endpoint when you need to programmatically construct well-formatted query strings for ONE Engine searches, especially in agentic workflows where search parameters are dynamic or derived from prior steps. Prefer this over manual string concatenation to ensure correct URL encoding and formatting.

## Known failure modes

- Missing or malformed value object in request body returns an error or empty query
- Unexpected field types in the value object may produce malformed query strings
- Network or worker-side errors may return 5xx responses
- Payment failure via x402 protocol results in 402 Payment Required before query is built

## How this service works

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

## Output

A JSON response containing a formatted query string (e.g. 'q=ONE+Engine&page=2') suitable for use as URL query parameters in a ONE Engine search request.

## Request schema (JSON Schema)

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

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "query": "q=ONE+Engine&page=2"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/one-engine-query-builder-cc1e3220/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)