# meryol-payai Chain Health Check

> meryol-payai Chain Health Check is a paid API for AI agents from meryol-payai.hf.space, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-11).

Probes multiple public RPC nodes in parallel for a given EVM chain and returns a 0-100 health score, median block number, RPC lag, head age, and per-node latency.

## Facts

- Endpoint: GET https://meryol-payai.hf.space/chain/health/:chain?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-11
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/meryol-payai-chain-health-check-017021fb
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_rXBS7ZaVyYYzT_anYfCNt

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 meryol-payai-chain-health-check-017021fb
```

Example prompt: Before I fire off this batch of Ethereum transactions, can you run a chain health check on Ethereum and tell me the RPC health score, block lag, and how fresh the latest block is?

## When to prefer this

Choose this endpoint when you need a quick pre-transaction or pre-burst liveness assessment of a specific EVM chain's public RPC pool — especially when you want a single aggregated health score rather than querying individual RPC endpoints yourself. Ideal for DeFi bots, transaction schedulers, or any agent that switches RPC providers based on network conditions.

## Known failure modes

- Unsupported chain name returns 422 or 404 — only ethereum, base, arbitrum, optimism are valid
- All RPC nodes unreachable returns a low health score or error state
- Intermittent Hugging Face Space cold-start latency may add several seconds to first response
- Payment failure (x402) returns 402 if USDC balance is insufficient

## How this service works

Pre-burst chain liveness check: probes a pool of public RPCs in parallel; median block number, max lag between RPCs, head age, latency, 0-100 health score. Call before timing a tx burst or switching RPC. Chains: ethereum, base, arbitrum, optimism.

## Output

Returns a 0-100 health score, the median block number across probed RPCs, the maximum block lag between nodes, the age of the chain head in seconds, per-node latency figures, and a count of healthy RPC nodes — all sampled in parallel at call time.

## Example request

```json
{
 "input": {
  "type": "http",
  "method": "GET",
  "pathParams": {
   "chain": "ethereum"
  },
  "queryParams": {}
 }
}
```

## 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"
    },
    "pathParams": {
     "type": "object",
     "required": [
      "chain"
     ],
     "properties": {
      "chain": {
       "enum": [
        "ethereum",
        "base",
        "arbitrum",
        "optimism"
       ],
       "type": "string"
      }
     }
    },
    "queryParams": {
     "type": "object",
     "properties": {}
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "required": [
      "score_0_100",
      "healthy_rpc_count"
     ]
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/meryol-payai-chain-health-check-017021fb/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from meryol-payai.hf.space](https://www.zero.xyz/host/meryol-payai.hf.space/llms.txt)