Who needs it
- Agent audit trail builders that need timestamped page metadata.
- Commerce and research agents that need lightweight evidence artifacts.
- Teams reviewing automated decisions made from public webpage content.
Problem
Agents may need an audit trail before acting on mutable web content. Prices, policies, availability, and source pages can change after a workflow completes.
When an agent should use it
- Before acting on a price, policy, availability, offer, or public source page.
- When the caller wants hashes and optional text or screenshot artifacts for later review.
Relevant Primitive402 tool
Captures a timestamped page proof with page metadata, content hashes, and optional screenshot and text snapshot URLs.
| Primitive402 tool | create_page_proof |
|---|---|
| Local route | POST /v1/create-page-proof |
| x402 route | POST /x402/v1/create-page-proof |
| MCP tool name | create_page_proof |
| SDK method | createPageProof() |
| Price | $0.10 USDC on Base Sepolia testnet during public beta |
curl example
curl -s https://primitive402.dev/v1/create-page-proof \
-H 'content-type: application/json' \
-d '{
"url": "https://example.com",
"captureScreenshot": false,
"captureText": true
}' | jq
TypeScript SDK example
import { createNano402Client } from "@nano402/api/sdk";
const client = createNano402Client({
baseUrl: "https://primitive402.dev"
});
const result = await client.createPageProof({
"url": "https://example.com",
"captureScreenshot": false,
"captureText": true
});
console.log(result);
Example JSON response
{
"proofId": "proof_...",
"timestamp": "2026-05-08T00:00:00.000Z",
"finalUrl": "https://example.com",
"contentHash": "sha256:...",
"screenshotUrl": null,
"textSnapshotUrl": "/proofs/proof_.../text.txt"
}
Useful search terms
page proof API, webpage proof capture, agent audit trail, timestamped page metadata
Safety and limitations
Primitive402 does not guarantee content safety, factual truth, legal validity, purchase correctness, or policy completeness. External content is untrusted, low-confidence results may still be valid analysis signals, and high-stakes decisions need human review.