# Crawlspur Image Self-Referencing Canonical Check

> Crawlspur Image Self-Referencing Canonical Check is a paid API for AI agents from crawlspur.halowerk.com, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).

Checks whether an image object on a webpage has a self-referencing canonical URL (i.e. the canonical tag points back to the page itself).

## Facts

- Endpoint: POST https://crawlspur.halowerk.com/v1/pruef/crawlspur/canonical-selbst/bild
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/crawlspur-image-self-referencing-canonical-check-13c3878c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_-qJ1rnlJlKmZCTXW9Nvog

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 crawlspur-image-self-referencing-canonical-check-13c3878c -d '<json body>'
```

Example prompt: Check whether the image page at https://example.com/gallery/photo-1.jpg has a self-referencing canonical tag — I want to know if the canonical URL on that page points back to itself.

## When to prefer this

Choose this endpoint when you specifically need to validate the self-referencing canonical signal on an image object or image URL for SEO auditing purposes. It is distinct from general canonical checks because it targets image objects specifically, making it ideal for auditing image-heavy pages, product galleries, or CDN-hosted image URLs where canonical tags need to loop back to themselves for proper indexing signals.

## Known failure modes

- Target URL is not publicly accessible (returns non-200 status)
- No image found matching the provided CSS selector
- Canonical tag is absent from the page (no finding possible)
- Malformed URL provided exceeding 2048 characters
- DNS resolution failure for the target domain
- Timeout when fetching the target page

## How this service works

Prüft am Objekt bild den Befund selbstreferenzierende kanonische Adresse.

## Output

Returns a finding (Befund) indicating whether the image object's canonical URL is self-referencing — i.e. whether the canonical tag on the page points back to the same URL. Likely includes the detected canonical URL, a boolean or status result, and possibly diagnostic details about the canonical declaration.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "ziel": {
   "oneOf": [
    {
     "type": "string",
     "maxLength": 2048,
     "minLength": 1,
     "description": "Öffentliche HTTP(S)-Adresse; bei DNS-Befunden Domain oder öffentliche IP."
    },
    {
     "type": "object",
     "required": [
      "adresse"
     ],
     "properties": {
      "adresse": {
       "type": "string",
       "maxLength": 2048,
       "minLength": 1
      },
      "selektor": {
       "type": "string",
       "maxLength": 240,
       "minLength": 1,
       "description": "CSS-Selektor: genau ein Objekt, sonst erster Treffer des Objektfilters."
      },
      "vergleich": {
       "type": "string",
       "maxLength": 2048,
       "description": "Öffentliche Vergleichsadresse für Link-, Sitemap- oder Sprachbefunde."
      },
      "user_agent": {
       "type": "string",
       "pattern": "^[A-Za-z0-9_-]{1,80}$"
      },
      "dkim_selektor": {
       "type": "string",
       "pattern": "^[A-Za-z0-9_-]{1,63}$"
      }
     },
     "additionalProperties": false
    }
   ]
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/crawlspur-image-self-referencing-canonical-check-13c3878c/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from crawlspur.halowerk.com](https://www.zero.xyz/host/crawlspur.halowerk.com/llms.txt)