# x402 Trust Layer Buy Advisor

> x402 Trust Layer Buy Advisor is a paid API for AI agents from x402trustlayer.xyz, paid per call via x402, $0.08/call, status unknown (last checked 2026-10-01).

Evaluates an API purchase intent against policy limits and returns ranked quotes with a recommended provider, cost, and action for x402-paid API calls

## Facts

- Endpoint: POST https://x402trustlayer.xyz/api/market/buy-advisor?utm_source=zero.xyz
- Price: $0.08/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-01
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-trust-layer-buy-advisor-d9f763ab
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_OjlyCl6qNKacoGDAgpbOo

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-trust-layer-buy-advisor-d9f763ab -d '<json body>'
```

Example prompt: I need to call an ETH/USD spot price oracle — can you check what the best x402 API option is for that, make sure it's within my daily spending policy, and tell me where to send the payment on Base?

## When to prefer this

Use this endpoint when an AI agent needs to decide which x402-compatible API to call for a given intent before committing to a micropayment — especially when policy compliance (daily/per-call spend limits) must be checked first, or when multiple competing providers exist and cost comparison is needed. Prefer over direct API calls when the agent doesn't already know the best provider or network for a capability.

## Known failure modes

- Policy disallowed: returns allowed=false with a policy summary explaining limit exceeded
- No matching providers: quotes array empty, recommendation may be absent
- Invalid HTTP method supplied (only GET, HEAD, DELETE allowed): schema validation error
- Service unavailable: non-200 response with ok=false
- Low confidence recommendation: confidence score below threshold with weak rationale

## How this service works

68 paid x402 trust infrastructure APIs: guard, semantic escrow, mandate diff, certified seller network, KYM, mandates, compliance, disputes, and orchestration.

## Output

Returns a policy evaluation (allowed/denied with summary), ranked quotes from available providers with all-in USDC cost, and a top recommendation including the endpoint URL, network (e.g. eip155:8453), required action (e.g. pay_external), confidence score, rationale, and total cost in USDC.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {}
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "required": [
      "status",
      "ok",
      "allowed",
      "summary",
      "intent",
      "checkedAt",
      "recommendation",
      "quotes",
      "policy"
     ],
     "properties": {
      "ok": {
       "type": "boolean"
      },
      "intent": {
       "type": "string"
      },
      "policy": {
       "type": "object",
       "required": [
        "evaluated",
        "allowed",
        "summary"
       ],
       "properties": {
        "allowed": {
         "type": "boolean"
        },
        "summary": {
         "type": "string"
        },
        "evaluated": {
         "type": "boolean"
        }
       }
      },
      "quotes": {
       "type": "array",
       "items": {
        "type": "object",
        "required": [
         "rank",
         "name",
         "allInCostUsdc",
         "requiresPayment"
        ],
        "properties": {
         "name": {
          "type": "string"
         },
         "rank": {
          "type": "number"
         },
         "allInCostUsdc": {
          "type": "number"
         },
         "requiresPayment": {
          "type": "boolean"
         }
        }
       }
      },
      "status": {
       "type": "string"
      },
      "allowed": {
       "type": "boolean"
      },
      "summary": {
       "type": "string"
      },
      "checkedAt": {
       "type": "string"
      },
      "recommendation": {
       "type": "object",
       "required": [
        "action",
        "url",
        "network",
        "allInCostUsdc",
        "confidence",
        "rationale"
       ],
       "properties": {
        "url": {
         "type": "string"
        },
        "action": {
         "type": "string"
        },
        "network": {
         "type": "string"
        },
        "rationale": {
         "type": "string"
… (truncated)
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "ok": true,
  "intent": "ETH USD spot price oracle",
  "policy": {
   "allowed": true,
   "summary": "Within daily and per-call limits",
   "evaluated": true
  },
  "quotes": [
   {
    "name": "Example API",
    "rank": 1,
    "allInCostUsdc": 0.05,
    "requiresPayment": true
   }
  ],
  "status": "ok",
  "allowed": true,
  "summary": "Best catalog match: Mycelia ETH/USD Oracle at ~$0.05 on eip155:8453.",
  "checkedAt": "1970-01-01T00:00:00.000Z",
  "recommendation": {
   "url": "https://api.example.com/oracle/eth/usd",
   "action": "pay_external",
   "network": "eip155:8453",
   "rationale": "Best catalog match within policy caps",
   "confidence": 0.85,
   "allInCostUsdc": 0.05
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-trust-layer-buy-advisor-d9f763ab/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402trustlayer.xyz](https://www.zero.xyz/host/x402trustlayer.xyz/llms.txt)