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Umpire Witness Verdict
x402
Umpire Witness Verdict is a paid API for AI agents from umpire.vimabrosta.com, paid per call via x402, $0.25/call, status unknown (last checked 2026-09-14).
Probes a live public URL against your expectation and returns a cryptographically signed Ed25519 verdict with network-level evidence (TLS fingerprint, resolved address, response headers, body hash, timestamp).
Price / call$0.25
Success—
StatusUnknown
How this service works
Proof that the world changed the way your agent says it did. One live probe of a public URL against your expectation (HTTP status, keyword, CSS selector, JSON path), answered synchronously as an Ed25519 signed verdict that embeds a signed observation: final URL, resolved address, TLS certificate fingerprint, response headers, raw body sha256, timestamp. A stake free witness against false success, priced to clear unattended wallet caps. $0.25 per verdict, no account.
Output
A synchronously returned Ed25519-signed verdict object containing: pass/fail result, the specific checks run, the final resolved URL, the IP address, TLS certificate fingerprint, response headers, a SHA256 hash of the raw body, and a timestamp — all cryptographically signed to prevent tampering or fabrication.
Example use cases
Verify agent-claimed task completion
“My AI agent says it posted a report to https://myapp.com/output/run-42.json — can you get a signed witness verdict confirming that URL is reachable and the JSON field 'completed' is true? Use job_ref 'run-42-verify'.”
Confirm live payment page before releasing funds
“Before I approve the payout, can you probe https://vendor.com/invoice/INV-2024 and get a cryptographically signed verdict verifying it returns HTTP 200 and contains the keyword 'INV-2024'?”
Audit a content deliverable URL
“I need tamper-evident proof that https://cdn.partner.com/assets/final-logo.png exists right now and matches SHA256 hash abc123def456 — can you run a content_hash check and get me the signed verdict with the TLS fingerprint and timestamp?”
Technical details
Endpoint
POSThttps://umpire.vimabrosta.com/v1/verdicts/witnessWhen to prefer
Choose this endpoint when you need cryptographic, tamper-evident proof that a URL returned specific content at a specific time — especially in agentic workflows where one agent must verify another agent's claims, or when releasing payments contingent on a deliverable being live. Prefer this over simple HTTP checks when non-repudiation and signed evidence matter, and over monitoring services when you need a one-shot synchronous verdict rather than continuous polling.
Side effects
- URL is unreachable or returns non-200 status — verdict will reflect failure with observed status
- Check condition not met (keyword absent, JSON path missing) — verdict returns fail with evidence
- TLS handshake failure or invalid certificate — probe fails with TLS error details
- Invalid check type or malformed spec — 400 error returned before probe is attempted
- Payment not provided or insufficient — 402 response, no verdict issued
- Webhook URL provided but unreachable — probe may still succeed but delivery fails
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Tags
x402
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