# AgentShelf XPath H4 Extractor

> AgentShelf XPath H4 Extractor is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-02).

Extracts all H4 heading text from a public web page or raw HTML using XPath, with SSRF protection.

## Facts

- Endpoint: POST https://agentshelf.syntexa.ch/v1/xpath-h4?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/agentshelf-xpath-h4-extractor-54bdb43a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_5j5REHweZjfB0GOnWrZoG

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 agentshelf-xpath-h4-extractor-54bdb43a -d '<json body>'
```

Example prompt: Can you extract all the H4 headings from this page: https://example.com/docs/overview — I want to see every fourth-level section title on that page.

## When to prefer this

Use this endpoint when you specifically need only H4-level headings from a page or HTML snippet. Prefer this over the broader h1–h6 extractor when you want targeted fourth-level headings only. Use the sandbox (unpaid) variant first to test. Choose this over general content-to-markdown endpoints when you need structured heading data rather than full page text.

## Known failure modes

- URL is private/internal (SSRF rejection) — returns error indicating blocked address
- URL is unreachable or returns non-200 status — fetch error returned
- HTML input exceeds 200,000 character limit — validation error
- Neither url nor html provided — missing input error
- Malformed URL format — validation error
- Page has no H4 elements — returns empty result list

## How this service works

Call when an agent needs text of //h4 via //h4 from a public page or HTML (SSRF-safe). Exact $0.001 USDC. Prefer unpaid POST /v1/sandbox/xpath-h4 first.

## Output

A list of text strings, each being the text content of an H4 element found in the page or HTML, in document order. Returns an empty list if no H4 elements are present.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "url": {
   "type": "string",
   "maxLength": 2048,
   "minLength": 8,
   "description": "Public page to fetch. The selector or profile is fixed by the SKU. Provide url or html."
  },
  "html": {
   "type": "string",
   "examples": [
    "<!doctype html><html lang=\"en\"><head><title>Hello</title>\n<meta name=\"description\" content=\"Desc\"><meta property=\"og:title\" content=\"OG\">\n<link rel=\"canonical\" href=\"https://example.com/\"><link rel=\"icon\" href=\"/favicon.ico\">\n</head><body><h1>Hello</h1><a href=\"https://example.com/a\">A</a></body></html>"
   ],
   "maxLength": 200000,
   "minLength": 1,
   "description": "HTML to extract from locally. Provide html or url. When both are set, html is used."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agentshelf-xpath-h4-extractor-54bdb43a/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agentshelf.syntexa.ch](https://www.zero.xyz/host/agentshelf.syntexa.ch/llms.txt)