# BlindOracle Receipt Verifier

> BlindOracle Receipt Verifier is a paid API for AI agents from api.craigmbrown.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-12).

Verifies a BlindOracle receipt end-to-end: checks proof_id presence in the append-only proof rail, validates payload hash, verifies HMAC-SHA256 signature, recomputes content_sha256, and confirms the Base payment — returning a structured PASS/FAIL verdict.

## Facts

- Endpoint: POST https://api.craigmbrown.com/v1/services/trust.receipt-verify?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-12
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/blindoracle-receipt-verifier-7225143d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_7A7aZbh4U2G-4MkuZtTmu

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 blindoracle-receipt-verifier-7225143d -d '<json body>'
```

Example prompt: Can you fully verify this BlindOracle receipt for me — check that the proof_id is in the proof rail, confirm the payload hash and HMAC-SHA256 signature are valid, and verify the Base payment? Here's the receipt: {paste receipt JSON here}.

## When to prefer this

Use this endpoint when you have received a BlindOracle receipt from a counterparty and need a single, authoritative, server-side verification covering the parts a buyer cannot self-check alone — specifically: proof rail membership, HMAC-SHA256 signature validation against the signing key, and Base payment confirmation. Prefer this over the free self-checkable skill (RQ-BO-RECEIPT-VERIFY-01) when you need the seller-side checks that require access to BlindOracle's internal signing key and proof database.

## Known failure modes

- proof_id not found in BlindOracle proof rail — returns FAIL verdict
- payload hash mismatch — content has been tampered with, returns FAIL
- HMAC-SHA256 verification failure — signing key mismatch, returns FAIL
- Base payment not confirmed on-chain — returns FAIL or INCONCLUSIVE
- Malformed or incomplete receipt input — may return INCONCLUSIVE
- BlindOracle proof rail temporarily unavailable — returns INCONCLUSIVE

## How this service works

Verify a BlindOracle receipt against the parts a buyer cannot check alone: is the proof_id really in BlindOracle's append-only proof rail, does its payload still hash to the stored row, and does the row's HMAC-SHA256 verify against the signing key. Also recomputes content_... | BlindOracle by Craig M. Brown (craigmbrown.com) - counterparty-risk infrastructure sold to autonomous AI agents; self-built multi-agent framework (42+ agents); ERC-8004 agent passport #60979; paid via x402 in USDC on Base

## Output

A JSON object containing a verdict enum (PASS, PASS_WITH_GAPS, FAIL, or INCONCLUSIVE), an array of individual check results, a bo_trust object with BlindOracle-specific trust data, a list of seller-side checks performed, and a list of self-checkable checks — giving a complete picture of receipt authenticity.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "prompt": {
   "type": "string",
   "example": "{\"tx\": \"0x0252f07f66af83c4196428fdb52c4e351bf74091be735d0ffd7249b3e55ad5e2\"}"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "schema": {
  "type": "object",
  "properties": {
   "checks": {
    "type": "array",
    "items": {
     "type": "object"
    }
   },
   "verdict": {
    "enum": [
     "PASS",
     "PASS_WITH_GAPS",
     "FAIL",
     "INCONCLUSIVE"
    ],
    "type": "string"
   },
   "bo_trust": {
    "type": "object"
   },
   "seller_side_checks": {
    "type": "array",
    "items": {
     "type": "string"
    }
   },
   "self_checkable_checks": {
    "type": "array",
    "items": {
     "type": "string"
    }
   }
  }
 },
 "example": {
  "verdict": "PASS"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/blindoracle-receipt-verifier-7225143d/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.craigmbrown.com](https://www.zero.xyz/host/api.craigmbrown.com/llms.txt)