# agentshelf.syntexa.ch HTTP Headers Fetcher

> agentshelf.syntexa.ch HTTP Headers Fetcher is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-01).

Fetches response headers from a public URL using an SSRF-safe HEAD or GET request

## Facts

- Endpoint: POST https://agentshelf.syntexa.ch/v1/http-headers?utm_source=zero.xyz
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-01
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agentshelf-syntexa-ch-http-headers-fetcher-b5e70f52
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_ZwVOXPCHcZ9pPPycm9gbD

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-syntexa-ch-http-headers-fetcher-b5e70f52 -d '<json body>'
```

Example prompt: Can you fetch the response headers for https://example.com using a HEAD request so I can see what server and cache settings it uses?

## When to prefer this

Use this endpoint when an agent needs to inspect HTTP response headers for a public URL without downloading the full body. Prefer it over full-page scraping endpoints when only header metadata (Content-Type, server info, CORS, redirects, caching) is needed. If a free sandbox version is available at POST /v1/sandbox/http-headers, prefer that first to save cost.

## Known failure modes

- URL is blocked by SSRF protection (private IP range, localhost, internal hostname)
- Target server times out or is unreachable
- URL is malformed or under 8 characters
- Unsupported method value (not HEAD or GET)
- Target returns non-standard or empty headers

## How this service works

Call when an agent needs response headers from an SSRF-safe HEAD or GET of a public URL. Exact $0.003 USDC. Prefer unpaid POST /v1/sandbox/http-headers first.

## Output

Returns the HTTP response headers from the target URL as key-value pairs, including headers like Content-Type, Server, Cache-Control, X-Frame-Options, Location, and others returned by the server.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "url": {
   "type": "string",
   "examples": [
    "https://example.com/"
   ],
   "maxLength": 2048,
   "minLength": 8,
   "description": "Public http(s) URL. Private hosts are rejected."
  },
  "method": {
   "enum": [
    "HEAD",
    "GET"
   ],
   "type": "string",
   "examples": [
    "HEAD"
   ],
   "description": "HEAD or GET. Omit it to try HEAD and fall back to GET."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agentshelf-syntexa-ch-http-headers-fetcher-b5e70f52/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)