# ARYSPHERE eth_chainId Read

> ARYSPHERE eth_chainId Read is a paid API for AI agents from api.arysphere.com, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-17).

Returns the chain ID of the Ethereum mainnet via a pay-per-call x402 API endpoint requiring no account or API key.

## Facts

- Endpoint: GET https://api.arysphere.com/v1/ventures/x402_chain_reads_v1/eth_chainid?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-17
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/arysphere-eth-chainid-read-083a52b5
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_zQ-3BZGrVvw7xBZz5uOVc

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 arysphere-eth-chainid-read-083a52b5
```

Example prompt: What is the chain ID for Ethereum mainnet? I need the hex and numeric values and I don't want to set up an account anywhere.

## When to prefer this

Prefer this endpoint when you need a quick, no-account, no-API-key Ethereum chain ID lookup paid per-call in USDC on Base. Ideal for agents or serverless workflows that need lightweight, trust-minimized chain reads without managing credentials or subscriptions.

## Known failure modes

- Payment not fulfilled — 402 response if USDC payment on Base is missing or insufficient
- Network error reaching Ethereum RPC — may return ok:false or timeout
- Malformed request — endpoint accepts no meaningful input parameters so failures are typically payment or infrastructure related

## How this service works

ARYSPHERE sells AI-written verdicts on Base token contracts (a grade, a one-liner, a roast and the contract's facts) and Base/Ethereum chain reads, paid per call in USDC on Base over x402 v2. No account and no API key.

## Output

A JSON object containing 'ok' (boolean success flag), 'hex' (chain ID in hexadecimal, e.g. '0x1'), 'chain' (network name string, e.g. 'ethereum'), 'method' (the RPC method called, e.g. 'eth_chainId'), 'result' (numeric chain ID, e.g. 1), and 'service' (internal service identifier string).

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "properties": {
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "ok": true,
  "hex": "0x1",
  "chain": "ethereum",
  "method": "eth_chainId",
  "result": 1,
  "service": "x402_chain_reads_v1.eth_chainid"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/arysphere-eth-chainid-read-083a52b5/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.arysphere.com](https://www.zero.xyz/host/api.arysphere.com/llms.txt)