# AgentShelf Profile Rel Canonical Extractor

> AgentShelf Profile Rel Canonical Extractor is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.006/call, status unknown (last checked 2026-10-01).

Extracts the canonical URL from link[rel='canonical'] tags in a public webpage or HTML content

## Facts

- Endpoint: POST https://agentshelf.syntexa.ch/v1/profile-rel-canonical?utm_source=zero.xyz
- Price: $0.006/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-01
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agentshelf-profile-rel-canonical-extractor-d69f1d77
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_OoK55SF4JKFPwA3e0Hctp

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-profile-rel-canonical-extractor-d69f1d77 -d '<json body>'
```

Example prompt: Can you extract the canonical URL from https://example.com/blog/my-article — I need the value from its link rel='canonical' tag?

## When to prefer this

Choose this endpoint when you specifically need to extract the canonical URL (link[rel='canonical']) from a webpage or HTML fragment, especially for SEO auditing, deduplication, or metadata enrichment workflows. Prefer the free sandbox endpoint (/v1/sandbox/profile-rel-canonical) for testing. Use this paid endpoint when you need reliable, SSRF-safe extraction in production. If you need other link[rel] values (not just canonical), use the sibling link[rel] extractor instead.

## Known failure modes

- URL is unreachable or returns non-200 status — extraction fails with network error
- HTML does not contain a link[rel='canonical'] tag — returns empty/null result
- URL points to internal/private network resource — blocked for SSRF safety
- HTML content exceeds 200,000 character limit — request rejected
- Malformed HTML prevents tag parsing — may return empty result
- URL string shorter than 8 or longer than 2048 characters — validation error

## How this service works

Call when an agent needs link rel tokens that equal canonical extracted from a public page or HTML (SSRF-safe). Exact $0.006 USDC. Prefer unpaid POST /v1/sandbox/profile-rel-canonical first.

## Output

Returns the value of the href attribute from the link[rel='canonical'] tag found in the page or HTML, typically a fully-qualified canonical URL string. Returns null or an empty result if no canonical tag is 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-profile-rel-canonical-extractor-d69f1d77/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)