# ChainRead Transaction Lookup

> ChainRead Transaction Lookup is a paid API for AI agents from api.firstmention.uk, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-29).

Fetches and risk-scores a blockchain transaction by hash on Base or Ethereum, returning flags, a risk score, and a verdict.

## Facts

- Endpoint: POST https://api.firstmention.uk/s/chainread/tx?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-29
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/chainread-transaction-lookup-a3177be6
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_QrZxpbWS88zNH5xHFkoHW

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 chainread-transaction-lookup-a3177be6 -d '<json body>'
```

Example prompt: Can you look up transaction 0x4a3b...c9f2 on Base and tell me if it's risky — I need the risk score and any flags before I proceed?

## When to prefer this

Use this endpoint when you need a quick, pay-per-call risk score and flag breakdown for a specific transaction hash on Base or Ethereum without setting up your own blockchain node or analytics pipeline. It's ideal for agent workflows that need to gate actions on transaction risk before proceeding, or for compliance checks on individual transactions at minimal cost ($0.01 USDC).

## Known failure modes

- Invalid or malformed transaction hash returns an error
- Unsupported chain value (not 'base' or 'ethereum') causes validation failure
- Transaction hash not found on the specified chain returns not-found error
- Insufficient USDC balance or x402 payment failure blocks the call
- Rate limiting or network timeouts on the RPC provider side

## How this service works

Pay-per-call HTTP APIs, paid with x402 in USDC on Base (eip155:8453): agentkit, api-change-check, basedue, basewatch, chainread, check-sanctions, chgwatch, company-facts, composite, edgar, feednews, pageaudit, solcheck, token-dd, txpreflight, walletcheck, webmd, webread, websearch, x402index. Each operation describes its service.

## Output

Returns a JSON object with a numeric risk score (0-100), a verdict string (e.g. CAUTION, SAFE, HIGH_RISK), an array of flag objects each containing a code and severity level, the chain name, the queried address or hash, and metadata including the payer wallet and price paid in USD.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "hash": {
   "type": "string",
   "description": "0x transaction hash (for /tx)"
  },
  "chain": {
   "enum": [
    "base",
    "ethereum"
   ],
   "type": "string"
  },
  "number": {
   "type": "string",
   "description": "Block number or 'latest' (for /block)"
  },
  "address": {
   "type": "string",
   "description": "0x address or ERC-20 contract address"
  },
  "addresses": {
   "type": "array",
   "items": {
    "type": "string"
   },
   "description": "Up to 25 addresses (for /batch)"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "risk": "medium",
  "_meta": {
   "payer": "0x...",
   "price_usd": 0.01
  },
  "chain": "base",
  "flags": [
   {
    "code": "owner_holds_power",
    "severity": "high"
   }
  ],
  "score": 45,
  "address": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
  "verdict": "CAUTION"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/chainread-transaction-lookup-a3177be6/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.firstmention.uk](https://www.zero.xyz/host/api.firstmention.uk/llms.txt)