# Annalist x402 Service Checker

> Annalist x402 Service Checker 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 an independent reliability and trust grade for an x402-compatible HTTP service, including uptime share, organic payer count, and flag reasons.

## Facts

- Endpoint: GET https://api.annalist.dev/v1/checks/service?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-service-checker-4d61ffb1
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_dwd8_XiqRSK5EK_e8M81-

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-service-checker-4d61ffb1
```

Example prompt: Can you check whether api.example.com is a trustworthy x402 service — I want to know its grade, uptime, and how many real users are actually paying for it before I integrate it?

## When to prefer this

Choose this endpoint when an AI agent needs to independently verify the trustworthiness, reliability, and organic usage of an x402-compatible HTTP service or MCP server before committing to paid calls. It is especially valuable when evaluating unfamiliar APIs discovered through x402scan or bazaar marketplaces, or when building agent workflows that require automated due diligence on third-party paid services.

## Known failure modes

- Unknown host: host not found in Annalist's index, returns empty or low-confidence result
- Invalid URL or host parameter: missing required query param returns error
- Service too new: insufficient data to grade, may return null reliability fields
- Network timeout: upstream check takes too long, returns partial data
- Non-x402 service queried: endpoint may return flags indicating service is not x402-compatible

## 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

A JSON object containing the host, a letter grade (e.g. 'B'), a list of flags (issues detected), human-readable reasons supporting the grade, organic payer count over the past 30 days, and a 7-day uptime share ratio — all independently assessed by Annalist.

## 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",
     "properties": {
      "url": {
       "type": "string",
       "description": "or any URL on the service"
      },
      "host": {
       "type": "string",
       "description": "host name, for example api.example.com"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "data": {
   "host": "api.example.com",
   "flags": [],
   "grade": "B",
   "usage": {
    "organic_payers_30d": 41
   },
   "reasons": [
    "quoted price matches listing"
   ],
   "reliability": {
    "up_share_7d": 0.98
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/annalist-x402-service-checker-4d61ffb1/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)