# IntentFence x402 Quote Verifier

> IntentFence x402 Quote Verifier is a paid API for AI agents from agentpass-protocol.rmalka06.chatgpt.site, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-15).

Verifies an x402 payment quote before an AI agent pays, checking the asset, price, payee, and resource binding for safety.

## Facts

- Endpoint: POST https://agentpass-protocol.rmalka06.chatgpt.site/api/x402-assessments
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/intentfence-x402-quote-verifier-8ae2e360
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_2dI0gEiFoPlgTv1E5EJKq

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 intentfence-x402-quote-verifier-8ae2e360 -d '<json body>'
```

Example prompt: Before you pay this x402 quote, run it through IntentFence first — check that the asset is Base USDC, the price looks right, and the payee and resource are legitimately bound, and only proceed if you get a safe_to_proceed status.

## When to prefer this

Use this endpoint when an AI agent is about to authorize an x402 micropayment and needs a caller-observed safety check before funds are sent. It is specifically designed for the x402 protocol on Base USDC, and is the right choice when you want a signed receipt and a structured IntentFence score rather than a simple format validation. Prefer it over no-op checks or generic schema validators when financial risk from a tampered payee or mispriced quote is a concern.

## Known failure modes

- Quote fails validation — payee or resource binding mismatch returns a non-safe status
- Asset is not Base USDC — quote is flagged as unsafe
- Price deviation detected — quote price does not match expected amount
- Malformed or missing x402 payment requirements in the request body
- Network or service errors returning non-200 responses
- Stale or replayed quote with mismatched SHA-256 hash

## How this service works

Fail-closed, action-bound authorization for AI agents with five-minute ES256 receipts, MCP risk scanning, and x402 payment safety.

## Output

A JSON object with a safety status (e.g. 'safe_to_proceed'), an IntentFence score, a verification tier, a SHA-256 hash of the observed payment requirements, a signed receipt with assurance label, and a unique request ID. This lets the agent confirm whether the quote is safe to pay before committing funds.

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "status": "safe_to_proceed",
  "receipt": {
   "signed": true,
   "assurance": "caller-observed-x402-quote-assessment"
  },
  "observed": {
   "x402_version": 2,
   "payment_requirements_sha256": "6902df25de3f5724ff75332b01efab618f7082e69cb3b541a99b6cd4cbf3a2a6"
  },
  "request_id": "7d7fbf44-3c39-4eca-89d6-b44d756c8df1",
  "intentfence": "0.6",
  "verification_tier": "x402-quote-assessment+x402-settled"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/intentfence-x402-quote-verifier-8ae2e360/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agentpass-protocol.rmalka06.chatgpt.site](https://www.zero.xyz/host/agentpass-protocol.rmalka06.chatgpt.site/llms.txt)