# AgentShelf CSS Header Extractor

> AgentShelf CSS Header Extractor is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.007/call, status unknown (last checked 2026-10-02).

Extracts the primary header text (H1/H2 CSS header) from a public URL or raw HTML string, with SSRF protection.

## Facts

- Endpoint: POST https://agentshelf.syntexa.ch/v1/css-header?utm_source=zero.xyz
- Price: $0.007/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agentshelf-css-header-extractor-d7224602
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_QtVDMfjybTta7WCtYfX0E

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-header-extractor-d7224602 -d '<json body>'
```

Example prompt: Can you grab the main header text from https://example.com/product-page for me?

## When to prefer this

Use this endpoint when you need to quickly extract just the primary header/heading text from a webpage or HTML blob, without needing full page content or metadata. Prefer this over general scrapers when header-only extraction is sufficient and cost efficiency matters. Use the unpaid sandbox POST /v1/sandbox/css-header first to test; fall back to this paid endpoint ($0.007 USDC) for production use or when the sandbox is unavailable.

## Known failure modes

- URL is unreachable or returns non-200 status — extraction fails with an error
- Provided HTML has no detectable header element — returns empty or null result
- URL points to a private/internal address blocked by SSRF protection — request rejected
- HTML content exceeds 200,000 character limit — input rejected
- URL shorter than 8 characters or longer than 2048 characters — validation error
- Page requires JavaScript rendering to display header — static extraction may return empty

## How this service works

Call when an agent needs header text via header from a public page or HTML (SSRF-safe). Exact $0.007 USDC. Prefer unpaid POST /v1/sandbox/css-header first.

## Output

Returns the extracted header/heading text found in the page or HTML, typically the H1 or primary CSS-styled header element. The response is a text string representing the most prominent heading on the page.

## 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-header-extractor-d7224602/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)