# Heading Outline Extractor (agentshelf.syntexa.ch)

> Heading Outline Extractor (agentshelf.syntexa.ch) is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-01).

Extracts an h1–h6 heading outline from a public URL or raw HTML, returning structured heading hierarchy.

## Facts

- Endpoint: POST https://agentshelf.syntexa.ch/v1/heading-outline?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-01
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/heading-outline-extractor-agentshelf-syntexa-ch-4d96d6cd
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_sBp1CPeDAw9yMHEec1aub

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 heading-outline-extractor-agentshelf-syntexa-ch-4d96d6cd -d '<json body>'
```

Example prompt: Can you pull the full h1-through-h6 heading outline from this page? The URL is https://example.com/blog/top-10-tips

## When to prefer this

Choose this endpoint when you need a structured h1–h6 outline from a public webpage or HTML blob and want a paid, reliable extraction with a fixed $0.002 USDC cost. Use the free sandbox POST /v1/sandbox/heading-outline first if available. Prefer this over generic scraping tools when only the heading hierarchy (not full page content) is needed.

## Known failure modes

- URL is not publicly accessible or returns a non-200 status — endpoint may return an error or empty outline
- HTML exceeds 200,000 character limit — request rejected
- URL string shorter than 8 characters or malformed — validation error
- Page has no heading elements — returns empty outline
- SSRF-protected: private/internal URLs may be blocked

## How this service works

Call when an agent needs an h1–h6 outline from a public URL or provided HTML. Exact $0.002 USDC. Prefer unpaid POST /v1/sandbox/heading-outline first.

## Output

Returns a structured list or outline of all h1–h6 heading elements found in the page or HTML, preserving their level and text content so the caller can see the document's section hierarchy at a glance.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "url": {
   "type": "string",
   "maxLength": 2048,
   "minLength": 8,
   "description": "Public http(s) URL to fetch. When html is also sent, this is only the base for relative links. Provide url or html."
  },
  "html": {
   "type": "string",
   "examples": [
    "<h1>Hello</h1><h2>Details</h2>"
   ],
   "maxLength": 200000,
   "minLength": 1,
   "description": "HTML to parse locally instead of fetching. When both html and url are set, html is used. Provide html or url."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/heading-outline-extractor-agentshelf-syntexa-ch-4d96d6cd/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)