# OnHub URL Context Q&A

> OnHub URL Context Q&A is a paid API for AI agents from x402.onhub.ai, paid per call via x402, $0.4/call, status unknown (last checked 2026-10-11).

Fetches and reads up to 3 public URLs, then answers a specific question grounded in their content with cited sources.

## Facts

- Endpoint: POST https://x402.onhub.ai/v1/url-context?utm_source=zero.xyz
- Price: $0.4/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-11
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/onhub-url-context-q-a-1e92f3e1
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_HdHESnQ1rFijROgQp9X_x

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 onhub-url-context-q-a-1e92f3e1 -d '<json body>'
```

Example prompt: Look at https://developers.cloudflare.com/changelog/ and https://blog.cloudflare.com/ and tell me: what are the most significant product changes Cloudflare announced this month?

## When to prefer this

Choose this endpoint when you need a factual, cited answer drawn from specific known URLs rather than a general web search. It is ideal when you already have the authoritative source URL and want an answer grounded in that exact content — such as reading documentation, changelogs, press releases, or public reports. Prefer it over a general search endpoint when source control and citation accuracy matter, and over raw scraping when you need a direct answer rather than raw HTML. Not suitable for video/audio URLs, paywalled content, or dynamically rendered single-page applications.

## Known failure modes

- URL is unreachable or returns non-200 status — source status will reflect failure, answer may be partial or empty
- URL points to paywalled, login-gated, or private network content — retrieval fails silently or returns empty body
- URL is a video or audio file — explicitly excluded by schema, will fail or be ignored
- Query is fewer than 3 characters — rejected by schema validation
- More than 3 URLs provided — rejected by schema validation
- Answer may be empty or low-quality if page content is JavaScript-rendered and not accessible via static fetch
- Query is unrelated to the URL content — answer returned but evidence_status may not be 'grounded'

## How this service works

OnHub is the pay-per-request API layer for agents. Text inference paid per request with USDC on Base.

## Output

A JSON object containing a grounded natural-language answer to the query, an array of source objects with the URL and retrieval status (e.g. URL_RETRIEVAL_STATUS_SUCCESS), and an evidence_status field (e.g. 'grounded') indicating whether the answer is supported by the fetched content. Inline citations like [1] appear in the answer text referencing source order.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "urls": {
   "type": "array",
   "items": {
    "type": "string",
    "format": "uri",
    "description": "A public HTTPS URL. No localhost, private networks, paywalled content, or video/audio."
   },
   "maxItems": 3,
   "minItems": 1
  },
  "query": {
   "type": "string",
   "maxLength": 2000,
   "minLength": 3,
   "description": "The question to answer using the content of the given URLs."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "query": "Summarize the key changes on this page",
  "answer": "The changelog highlights new Workers Builds. [1]",
  "object": "url_context.result",
  "sources": [
   {
    "url": "https://developers.cloudflare.com/changelog/",
    "status": "URL_RETRIEVAL_STATUS_SUCCESS"
   }
  ],
  "evidence_status": "grounded"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/onhub-url-context-q-a-1e92f3e1/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402.onhub.ai](https://www.zero.xyz/host/x402.onhub.ai/llms.txt)