Web Change Snapshot

Name: Web Change Snapshot
Price: 0.005 USDC

Live 0.005 USDC

Give the machine one public HTTPS URL and, optionally, a compact caller-held baseline. After payment it reuses VM01 URL Context fetch and extract, fingerprints the bounded normalized page, and reports whether that representation changed. It does not store a monitoring history, send alerts, or return the full page text.

PURPOSE

Plain-English job

Agents often need cheap webpage change detection, URL change, page freshness, documentation monitoring, pricing-page monitoring, or policy-page monitoring. Create a baseline, check later, and only call VM01 URL Context when current-page body context is required. The caller holds the baseline. Agent Mercantile does not keep a monitoring account.

WHEN TO CALL

Job-shaped selection

Call when you need webpage change detection, URL change, page freshness, documentation monitoring, pricing-page monitoring, or policy-page monitoring of one public HTTPS page. Not continuous monitoring, alerts, webhooks, semantic importance detection, AI summaries, or site-wide crawling. Sibling first-party machines are listed on GET /v1/catalog.

INPUT

URL plus optional baseline

Required url. Optional baseline is compact hashes and completeness/methodology fields only. Unexpected properties are rejected. Never resend the previous webpage body. Request body max 8192 bytes.

{
  "url": "https://example.com/"
}

OUTPUT

Health and comparison, separately

Product health is OK, PARTIAL, or HOLD. Comparison is BASELINE, UNCHANGED, CHANGED, or INCONCLUSIVE. Comparison covers the bounded normalized representation observed by VM07, not the entire website or entire webpage.

{
  "status": "OK",
  "machine": "VM07",
  "methodology_version": "web-change-snapshot-0.1.0",
  "comparison_status": "BASELINE",
  "changed_components": [],
  "extraction": {
    "basis": "body-heuristic",
    "truncated": false,
    "complete": true
  }
}

LIMITATIONS

Known bounds

BOUNDED REPRESENTATIONComparison covers fingerprints of final URL, HTTP state, title/description/canonical, headings, normalized main text, and JSON-LD types. Not the entire webpage.
INCOMPLETE IS HONESTTruncated or incomplete evidence cannot claim UNCHANGED. A changed fingerprint may still establish CHANGED.
NO MONITORING SERVICENo schedules, alerts, webhooks, cookies, or server-held page history.
NO LLM / NO BROWSERDeterministic extract reused from VM01. No headless renderer.
SAME SSRF PATHhttp, credentials-in-URL, non-443 ports, localhost, metadata hostnames, and non-public IP literals are rejected before a payable contract. Hostname DNS and public-IP classification reuse VM01 SSRF during the paid fetch, not as a pre-402 DNS preflight.

CONTRACT

Intended routes

Public API origin:

POST https://api.agentmercantile.com/v1/web-change-snapshot

GET https://api.agentmercantile.com/openapi.json

This page does not start a payment. Production verification is a separate post-deploy gate. Public contact: contact@agentmercantile.com.

DEVELOPER / API PAGE OPEN LIVE OPENAPI