# AgentShelf CSS H1 Extractor

> AgentShelf CSS H1 Extractor is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-01).

Extracts the text content of the first H1 element from a public URL or raw HTML, with SSRF protection.

## Facts

- Endpoint: POST https://agentshelf.syntexa.ch/v1/css-h1?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-01
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agentshelf-css-h1-extractor-50d42f91
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_kpumJPXAQ6Vdxylxt1UGn

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-css-h1-extractor-50d42f91 -d '<json body>'
```

Example prompt: What's the H1 heading text on this page: https://example.com/blog/some-article? Just pull the h1 element content for me.

## When to prefer this

Use this endpoint when you need to reliably extract only the H1 heading text from a public webpage or a known HTML blob, with built-in SSRF safety for server-side URL fetching. Prefer the free sandbox endpoint POST /v1/sandbox/css-h1 for testing or unpaid use cases. Choose this paid endpoint for production pipelines where SSRF protection and reliability matter. It is more focused than general HTML scraping services — ideal when all you need is the H1, not full-page content.

## Known failure modes

- URL is unreachable or returns a non-200 status — extraction fails
- No H1 element present in the HTML — returns empty or null result
- HTML exceeds 200,000 character limit — request rejected
- URL string shorter than 8 characters or longer than 2,048 characters — validation error
- SSRF protection blocks private/internal IP ranges — request rejected
- Malformed HTML may cause unexpected parsing results

## How this service works

Call when an agent needs h1 text via h1 from a public page or HTML (SSRF-safe). Exact $0.01 USDC. Prefer unpaid POST /v1/sandbox/css-h1 first.

## Output

Returns the text content of the first H1 element found in the provided URL's page or the supplied HTML string. If no H1 is present, the response likely returns an empty or null value. The extraction is SSRF-safe, meaning server-side request forgery protections are applied when fetching URLs.

## 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 charset=\"utf-8\"><meta name=\"description\" content=\"Desc\">\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-css-h1-extractor-50d42f91/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)