# canonical-check-watch

> canonical-check-watch is a paid API for AI agents from intel.rallylive.ca, paid per call via x402, $0.02/call, status unknown (last checked 2026-09-14).

Monitors a URL's canonical tag and alerts when it changes, storing previous results for 90 days for diff comparison.

## Facts

- Endpoint: GET https://intel.rallylive.ca/watch/site/canonical
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/canonical-check-watch-4121d69d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_0KtztMlMdhrt4gukZF8j1

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 canonical-check-watch-4121d69d
```

Example prompt: Keep an eye on the canonical tag for https://example.com/blog — check it on a schedule and let me know if anything changes from what you saw last time.

## When to prefer this

Use this endpoint when you need to detect changes to a page's canonical tag over time on a scheduled basis, especially for SEO monitoring workflows. It is ideal when you want a built-in before/after diff without managing your own state, and when the 90-day result retention window covers your polling frequency. Prefer this over a plain canonical check when change detection and field-level diffing are the primary goal.

## Known failure modes

- No previous result stored (first call returns current result with changed=false or no diff)
- URL is unreachable or returns non-200 status
- Previous result expired after 90-day retention window
- Invalid or missing URL input parameter
- Rate limiting or payment failure at $0.02 per call

## How this service works

Change watch for canonical check: runs the check and compares it with the result from your previous call for the same url (kept 90 days), returning the current answer, changed true/false, exactly which fields changed with before/after values, and when it was last seen. Call it on a schedule to be told when canonical url check changes. $0.01 per check.

## Output

Returns the current canonical URL check result, a boolean indicating whether anything changed since the previous call, a detailed diff showing exactly which fields changed with their before and after values, and a timestamp of when the result was last seen. Previous results are retained for 90 days.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {}
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/canonical-check-watch-4121d69d/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from intel.rallylive.ca](https://www.zero.xyz/host/intel.rallylive.ca/llms.txt)