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Agent Embassy — Prove URL Live (Signed Receipt)
x402
Agent Embassy — Prove URL Live (Signed Receipt) is a paid API for AI agents from agent-embassy.fly.dev, paid per call via x402, $0.25/call, status unknown (last checked 2026-10-11).
Fetches a given HTTPS URL and returns a signed, on-chain-verifiable receipt proving the page was live and returned HTTP 200 at a specific moment in time.
Price / call$0.25
Success—
StatusUnknown
How this service works
Agents pay for work and prove what happened.
Output
A JSON object containing: the tool name ('prove_it'), a chain array documenting the steps taken (request, authorization, action, proof, liability_boundary), a status field ('complete'), the payer account address, a verdict ('pass' or 'fail'), a unique receipt_id (e.g. 'emb_stu901'), and a receipt_version string ('embassy-receipt/1'). This receipt is signed and re-checkable, providing machine-verifiable proof of the URL's liveness at call time.
Example use cases
Freelance deliverable proof of publication
“I need to prove to my client that the landing page I built at https://clientsite.example.com/launch is live and returning a 200 — can you fetch it and give me a signed receipt they can verify independently?”
Agent pipeline audit trail
“After my agent posted the report to https://reports.internal.example.com/q2-summary, can you get a cryptographic receipt proving it was reachable and returned HTTP 200, so we have an auditable record?”
Smart contract condition verification
“Before we release escrow, I need a machine-verifiable proof that https://vendor.example.com/invoice/12345 is live — can you fetch it and return a signed outcome receipt?”
Technical details
Endpoint
POSThttps://agent-embassy.fly.dev/v1/check/prove?utm_source=zero.xyzWhen to prefer
Choose this endpoint when an AI agent needs tamper-evident, third-party-verifiable proof that a specific URL was live and returned HTTP 200 at a given moment — especially for smart contract conditions, freelance deliverable verification, audit trails, or any workflow where a human or system must independently verify that a web resource existed. Prefer this over a simple HTTP HEAD check when a signed, replayable receipt is required as evidence.
Side effects
- URL times out after 10 seconds — returns failure verdict
- URL returns non-200 HTTP status — verdict is 'fail' rather than 'pass'
- URL body exceeds 1MB cap — fetch is truncated or rejected
- More than 3 redirects encountered — fetch aborted
- Idempotency key reuse — returns original receipt without re-running the action
- Published/known example idempotency keys are rejected
- Credentials embedded in the URL are rejected
- Payment failure via x402 — request not processed
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| url | string | HTTPS URL to prove live (max 2000 chars; no credentials in URL). Fetched once; up to 3 redirects followed, 10s timeout, 1MB body cap. Default expectation: HTTP 200 |
| idempotency_key | string | Idempotency key: UUID v4, client-generated, one per logical request. Replaying the same key on this tool returns the original receipt — the action is not re-run, and the first request's receipt wins even if you resend different inputs. Published example keys are rejected. Keys are scoped per tool and per payer account: a key never returns another wallet's receipt. |
Output
Schema · Response
{
"type": "json",
"example": {
"tool": "prove_it",
"chain": [
"request",
"authorization",
"action",
"proof",
"liability_boundary"
],
"status": "complete",
"account": "0x1111111111111111111111111111111111111111",
"verdict": "pass",
"receipt_id": "emb_stu901",
"receipt_version": "embassy-receipt/1"
}
}Tags
x402
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