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FactStamp Watch Portfolio
x402
FactStamp Watch Portfolio is a paid API for AI agents from factstamp.agentrails.workers.dev, paid per call via x402, $5/call, status unknown (last checked 2026-10-16).
Starts a 30-day standing re-check subscription for up to 25 citations or package versions at once, returning signed receipts for any detected changes
Price / call$5
Success—
StatusUnknown
How this service works
Watch a whole list at once, when a bibliography or a dependency manifest has to stay true: up to 25 citations or package versions re-checked every day for 30 days under one token. US$5 a portfolio — 20 cents a reference, under a cent a check. Every reference is answered and signed on purchase, and each real change gets its own signed receipt. Nothing is sent when nothing changed. Pay per call here, or redeem a prepaid pack code (100 credits).
Output
Returns a one-time portfolio token, a portfolio ID, a read URL for polling current status, a stop URL to cancel, the expiry timestamp (30 days out), the item count, pricing breakdown, and payment settlement confirmation. Subsequent signed receipts are generated per item only when a real change is detected; nothing is sent when nothing changed.
Example use cases
Monthly bibliography integrity monitor
“I'm submitting a paper next month and want to make sure none of my 20 cited sources get retracted or updated before then — can you set up a 30-day FactStamp portfolio watch on all of them so I get signed receipts if anything changes?”
Dependency manifest continuous verification
“We have a requirements.txt with 18 packages that our production build depends on — please start a 30-day FactStamp portfolio watch on all of them so we're immediately alerted with a signed receipt if any version status changes.”
Legal document source monitoring
“I've got a contract that references 12 regulatory documents and I need to know within 30 days if any of those sources are amended or removed — can you set up a FactStamp portfolio watch on all 12 and give me the read URL to check status?”
Technical details
Endpoint
POSThttps://factstamp.agentrails.workers.dev/watch/portfolio?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need to monitor a whole bibliography or dependency manifest — not just a one-time check — and want daily automated re-checks with cryptographically signed change receipts over 30 days. It is more cost-effective than calling single-reference watch endpoints repeatedly for large lists (up to 25 items at $5 flat vs $5 per item). Prefer it over batch single-check endpoints when persistence and change alerting matter, not just a point-in-time answer.
Side effects
- Payment failure via x402 results in no portfolio being created
- Exceeding 25 references in the list returns a validation error
- Invalid or malformed citation/package identifiers may cause individual items to fail verification
- Prepaid pack code invalid or exhausted returns a redemption error
- Portfolio token lost after creation cannot be recovered (shown once only)
- Network timeout during creation may result in ambiguous payment state
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| outputrequired | object |
Output
Schema · Response
{
"type": "json",
"example": {
"token": "fp_7c2a… (shown once)",
"per_unit": "US$5 for 25 references over 30 days: US$0.20 a reference, about 0.67 of a cent a check.",
"read_url": "https://factstamp.agentrails.workers.dev/portfolio/3a91c05f8d21e44077",
"stop_url": "https://factstamp.agentrails.workers.dev/portfolio/3a91c05f8d21e44077/stop",
"paid_with": {
"rail": "x402_pay_per_call",
"settlement": {
"success": true
},
"list_price_usd": 5
},
"expires_at": "2026-11-05T06:30:00.000Z",
"item_count": 25,
"portfolio_id": "3a91c05f8d21e44077"
}
}Tags
x402
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