# Annalist x402 Seller Reputation Check

> Annalist x402 Seller Reputation Check is a paid API for AI agents from api.annalist.dev, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-14).

Returns reputation, payment history, and service grades for an x402 seller address, helping agents evaluate trustworthiness of x402 API providers

## Facts

- Endpoint: GET https://api.annalist.dev/v1/checks/seller?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/annalist-x402-seller-reputation-check-b4a3b9d3
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_1JAAe9LhQ3aqWZIhXnBce

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 annalist-x402-seller-reputation-check-b4a3b9d3
```

Example prompt: Before I start paying this x402 seller at 0xde48...abcd, can you check their Annalist reputation — how many payments they've processed in the last 30 days and what grade their services have?

## When to prefer this

Use this endpoint when an AI agent needs to independently verify the trustworthiness of an x402 API seller before committing to paid calls. It is uniquely suited for pre-flight checks in agentic workflows that autonomously spend USDC via x402, where integrating an unvetted seller could waste funds or expose the agent to unreliable services. Prefer this over general blockchain explorers because it aggregates payment volume and service-level grades specific to the x402 ecosystem.

## Known failure modes

- Invalid or malformed Ethereum address returns a 400 or validation error
- Unknown address with no recorded activity returns empty services array and zero payment count
- Network or upstream data unavailability may return a 503 or timeout
- Payment failure via x402 protocol prevents access to results

## How this service works

Signed data for AI agents, paid per call over x402. Hyperliquid crowd state, smart money and liquidations with what historically happened next, plus independent checks of x402 services and MCP servers.

## Output

Returns a JSON object with the seller's Ethereum address, 30-day payment count, and a list of services hosted under that seller with per-host letter grades (e.g. A, B, C) reflecting service quality and reliability checks.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "address"
     ],
     "properties": {
      "address": {
       "type": "string",
       "pattern": "^0x[0-9a-fA-F]{40}$"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "data": {
   "usage": {
    "payments_30d": 900
   },
   "address": "0xde48...",
   "services": [
    {
     "host": "api.example.com",
     "grade": "B"
    }
   ]
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/annalist-x402-seller-reputation-check-b4a3b9d3/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.annalist.dev](https://www.zero.xyz/host/api.annalist.dev/llms.txt)