# Agent Preflight — Change Check

> Agent Preflight — Change Check is a paid API for AI agents from preflight.lorensaisolutions.com, paid per call via x402, $0.05/call, status unknown (last checked 2026-09-16).

Compares a previous snapshot of a URL or page against its current state to detect changes and recommend actions for AI agents.

## Facts

- Endpoint: POST https://preflight.lorensaisolutions.com/v1/change-check
- Price: $0.05/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-16
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agent-preflight-change-check-c889cf56
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Gcfj_rzig-VI74ZUqIoPY

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 agent-preflight-change-check-c889cf56 -d '<json body>'
```

Example prompt: Check if anything has changed on that product page since last time — here's the previous snapshot I saved: '<previousSnapshot content>' — and tell me what changed and whether I should notify the user.

## When to prefer this

Use this endpoint when an AI agent needs to determine whether a previously captured page or data snapshot has changed over time, especially for price monitoring, content tracking, or e-commerce intelligence workflows. Prefer this over generic scraping endpoints when you already have a baseline snapshot and need field-level diff output with an actionable recommendation.

## Known failure modes

- Missing or malformed previousSnapshot returns a validation error
- Snapshot too large or unparseable may cause a processing error
- Network timeout if the current page is slow to load
- No changes detected returns changed: false with an empty changes array
- Invalid URL in snapshot may result in a fetch failure

## How this service works

Paid URL analysis, CAPTCHA and login detection, API discovery, product intelligence, change monitoring, and batch preflight for AI agents and agent swarms.

## Output

Returns a JSON object with a boolean 'changed' field, an array of 'changes' each describing the field name, before and after values, and a 'recommendedAction' string (e.g. 'notify_user') advising the agent on next steps.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "previousSnapshot": {
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "changed": true,
  "changes": [
   {
    "after": "44.00",
    "field": "priceDetected",
    "before": "49.00"
   }
  ],
  "recommendedAction": "notify_user"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agent-preflight-change-check-c889cf56/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from preflight.lorensaisolutions.com](https://www.zero.xyz/host/preflight.lorensaisolutions.com/llms.txt)