# SignalHarness Address Checksum

> SignalHarness Address Checksum is a paid API for AI agents from signalharness.ai, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-13).

Converts an Ethereum-style address to its EIP-55 checksummed form and returns any associated warnings

## Facts

- Endpoint: POST https://signalharness.ai/api/agent/services/address_checksum/invoke
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/signalharness-address-checksum-08803642
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_JiIHlWt1bjsUtSHWiTIg1

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 signalharness-address-checksum-08803642 -d '<json body>'
```

Example prompt: Can you checksum this Ethereum address for me: 0xd8da6bf26964af9d7eed9e03e53415d37aa96045? I need the properly capitalized EIP-55 version.

## When to prefer this

Choose this endpoint when you need a simple, fast, paid-per-call API to normalize Ethereum addresses to EIP-55 mixed-case checksum format, especially within agent workflows that already use x402 micropayments on Base. It is purpose-built for blockchain address normalization and returns structured output with a receipt, making it suitable for audit trails in agent pipelines.

## Known failure modes

- Invalid or unparseable address string returns an error or warnings in the result
- Address string too short (under 2 characters) or exceeds 65536 characters will be rejected by schema validation
- Non-hex or malformed address may produce warnings rather than a hard failure
- Network or payment failures may result in a non-succeeded status in the receipt

## How this service works

Explore 330 pay-per-call x402 API services and 27 agent-native digital products, with Base USDC pricing, secure Polar checkout, and free discovery.

## Output

Returns the EIP-55 checksummed version of the submitted Ethereum address, along with any warnings about the input, an evidence scope field indicating the data source, and a service ID. Also includes a full execution receipt with payment details, latency, and a SHA-256 hash of the result.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "address_checksum_request": {
   "type": "string",
   "maxLength": 65536,
   "minLength": 2
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "replay": false,
  "result": {
   "warnings": [
    "Checksum normalization does not prove ownership or contract identity."
   ],
   "service_id": "address_checksum",
   "evidence_scope": "caller_supplied_data",
   "checksummed_address": "{\"address\":\"0x0000000000000000000000000000000000000001\"}"
  },
  "status": "succeeded",
  "receipt": {
   "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
   "usage": [],
   "status": "succeeded",
   "network": "eip155:8453",
   "artifacts": [],
   "endedAtMs": 0,
   "latencyMs": 0,
   "paymentId": "example-payment",
   "receiptId": "example-receipt",
   "requestId": "example-request",
   "serviceId": "address_checksum",
   "executionId": "example-execution",
   "startedAtMs": 0,
   "amountAtomic": "5000",
   "resultSha256": "06bd30b59a10c7002c04b6cd85eb68b782ba7e432fa3224547e7f818f7937fbf",
   "serviceVersion": "1.0.0",
   "settlementReference": "0x0000000000000000000000000000000000000000000000000000000000000000"
  },
  "artifacts": [],
  "requestId": "example-request",
  "executionId": "example-execution"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/signalharness-address-checksum-08803642/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from signalharness.ai](https://www.zero.xyz/host/signalharness.ai/llms.txt)