# SignalHarness EVM Confirmations Calculator

> SignalHarness EVM Confirmations Calculator is a paid API for AI agents from signalharness.ai, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-16).

Calculates the number of EVM blockchain confirmations required for a given transaction scenario, returning a reasoned recommendation with warnings.

## Facts

- Endpoint: POST https://signalharness.ai/api/agent/services/evm_confirmations_calculate/invoke
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-16
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/signalharness-evm-confirmations-calculator-77b04fca
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_G_x84kr-Pf-jzXjsL_rTi

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-evm-confirmations-calculator-77b04fca -d '<json body>'
```

Example prompt: I'm about to release funds after receiving a 5 ETH transfer on Base — can you calculate how many EVM confirmations I should wait for before considering it final and safe to act on?

## When to prefer this

Choose this endpoint when you need a programmatic, agent-callable recommendation for how many EVM block confirmations to require before treating a transaction as final — especially when the confirmation threshold depends on transaction value, network, or context that varies per call. Prefer this over hardcoded confirmation counts or manual lookup tables when building automated payment release systems, exchange deposit crediting, or DeFi protocol triggers.

## Known failure modes

- Empty or malformed confirmation_request string returns an error
- Request string exceeding 65536 characters is rejected
- Ambiguous or insufficient transaction context may produce warnings rather than a definitive answer
- Payment failure (x402) results in no service execution
- Network or execution timeout returns a failed 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 a JSON object containing a confirmation_calculation string with the recommended number of confirmations, an array of warnings about edge cases or risks, an evidence_scope field indicating the data basis (e.g. 'caller_supplied_data'), a status field ('succeeded'), and a full receipt object with payment metadata, execution IDs, latency, and a SHA-256 hash of the result for auditability.

## Request schema (JSON Schema)

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

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "replay": false,
  "result": {
   "warnings": [
    "Current height and inclusion must be caller supplied."
   ],
   "service_id": "evm_confirmations_calculate",
   "evidence_scope": "caller_supplied_data",
   "confirmation_calculation": "{\"confirmations\":\"11\",\"current_block\":\"100\",\"inclusion_block\":\"90\"}"
  },
  "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": "evm_confirmations_calculate",
   "executionId": "example-execution",
   "startedAtMs": 0,
   "amountAtomic": "5000",
   "resultSha256": "e90248174cd7a7bc41582de1a9eeb06279cc7ef919ab313fb21ef801807eebef",
   "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-evm-confirmations-calculator-77b04fca/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)