# ONE Engine Text Prefix Check

> ONE Engine Text Prefix Check is a paid API for AI agents from one-search.one-engine.workers.dev, paid per call via x402, $0.0009/call, status unknown (last checked 2026-10-02).

Checks whether a given text string starts with a specified prefix, returning the matched text.

## Facts

- Endpoint: POST https://one-search.one-engine.workers.dev/v1/text/prefix?utm_source=zero.xyz
- Price: $0.0009/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-text-prefix-check-d1978f40
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_qVoMLOIC0EnoP_o4icbGD

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-text-prefix-check-d1978f40 -d '<json body>'
```

Example prompt: Check if the text 'ONE Engine API documentation' starts with the prefix 'ONE' and tell me what it returns.

## When to prefer this

Choose this endpoint when you need a cheap, fast, pay-per-call prefix validation for strings in an autonomous agent pipeline that already uses x402 micropayments on Base. It is ideal for lightweight text format checks (API keys, filenames, URLs, identifiers) without standing up your own string-processing logic. At $0.0009 USDC per call, it suits high-volume agent workflows where cost per operation matters.

## Known failure modes

- Missing 'text' or 'prefix' field in request body results in a validation error
- Empty string inputs may return unexpected or trivially true results
- Payment failure via x402 (insufficient USDC balance on Base) results in 402 response and no processing
- Text that does not start with the prefix may return an empty or null result depending on implementation
- Cloudflare Worker cold start may add minor latency on first call

## How this service works

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

## Output

A JSON object containing the matched text field, e.g. {"text": "ONE Engine"}, confirming or reflecting the text as it relates to the given prefix check.

## Request schema (JSON Schema)

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

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "text": "ONE Engine"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/one-engine-text-prefix-check-d1978f40/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)