# x402 Receipt Tier Verifier

> x402 Receipt Tier Verifier is a paid API for AI agents from x402.167-172-95-184.nip.io, paid per call via x402, $0.05/call, status down (last checked 2026-10-03).

Verifies and classifies agent receipt evidence into tiers (transport ACK, handler ACK, semantic reply, domain receipt, human approval) with a confidence score and completion recommendation.

## Facts

- Endpoint: POST https://x402.167-172-95-184.nip.io/receipt/verify?utm_source=zero.xyz
- Price: $0.05/call
- Payment: x402
- Status: down
- Last checked: 2026-10-03
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-receipt-verification-api-edc26c0c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_tkoCgFtyqMdOUF7oilAkp

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 x402-receipt-verification-api-edc26c0c -d '<json body>'
```

Example prompt: Can you verify this receipt payload from my agent swarm and tell me what tier it is, whether the handler ACK and semantic reply are detected, and whether I'm missing anything before marking the task as done?

## When to prefer this

Use this endpoint when you need to programmatically determine whether an agent's task completion evidence meets a sufficient threshold to be marked done — particularly in multi-agent swarms where you need to distinguish between a bare transport acknowledgment and a semantically confirmed, domain-verified receipt. Prefer this over manual inspection when automating agent workflow state transitions.

## Known failure modes

- Malformed or empty receipt payload returns a low score with all detected signals false
- Missing required acknowledgment layers results in a low tier classification with a 'do not mark done' recommendation
- Network field may be absent if receipt does not include chain context
- Ambiguous or partial receipt data may be classified conservatively at a lower tier than actual completion
- Payment failure (insufficient USDC) results in HTTP 402 before the endpoint is reached

## How this service works

Agent-commerce trust/audit API for x402 challenge correctness, receipts, replay/context binding, failed payout triage, mandate readiness, and MCP/A2A discoverability.

## Output

Returns a JSON object with: receipt tier (e.g. R3_SEMANTIC_REPLY), a numeric confidence score (0-100), the network (e.g. 'base'), a detected signals map showing which of transport_ack/handler_ack/domain_receipt/semantic_reply were found, a Unix timestamp, a human-readable recommendation, and a list of missing artifacts required before the task can be marked complete.

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "tier": "R3_SEMANTIC_REPLY",
  "score": 72,
  "network": "base",
  "detected": {
   "handler_ack": true,
   "transport_ack": true,
   "domain_receipt": false,
   "semantic_reply": true
  },
  "timestamp": 1780000000,
  "recommendation": "Do not mark done until public/domain artifact or independent verifier receipt is attached.",
  "missing_for_done": [
   "domain_receipt",
   "verifier_receipt"
  ]
 },
 "description": "Receipt-tier verifier for agent swarms: classifies transport ACK, handler ACK, semantic reply, domain receipt, and human approval evidence."
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-receipt-verification-api-edc26c0c/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402.167-172-95-184.nip.io](https://www.zero.xyz/host/x402.167-172-95-184.nip.io/llms.txt)