# SignalHarness Base Event Log Decoder

> SignalHarness Base Event Log Decoder is a paid API for AI agents from signalharness.ai, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-15).

Decodes and analyzes raw Base blockchain event logs, returning structured event data including event name, arguments, block context, and network metadata

## Facts

- Endpoint: POST https://signalharness.ai/api/agent/services/base_event_log_decode/invoke
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/signalharness-base-event-log-decoder-12e5e251
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_KRqXTHkAy2gEcxVAij88B

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-base-event-log-decoder-12e5e251 -d '<json body>'
```

Example prompt: Can you decode this Base blockchain event log for me and tell me what event was emitted, who the sender and receiver were, and what value was transferred? Here's the raw log JSON: {"address":"0xabc...","topics":[...],"data":"0x...","blockNumber":"0x1234"}

## When to prefer this

Choose this endpoint when you need to decode raw EVM event logs specifically from the Base L2 network (mainnet chain ID 8453 or testnet 84532) into human-readable structured data. It is particularly useful when working with OP Stack-based transaction receipts and you need event name, argument extraction, and Base-specific network context in a single call. Prefer alternatives if you need full transaction tracing, multi-chain log decoding across arbitrary networks, or on-chain verification of log authenticity.

## Known failure modes

- Malformed or invalid log JSON causes parsing failure
- Unrecognized ABI or event signature results in undecoded output
- Caller-supplied logs are not independently verified — results may reflect tampered data
- Log from unsupported network (non-Base chain) may return incorrect network context
- Missing required fields in request_json returns validation error

## 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 the decoded event name, structured argument key-value pairs (e.g. from, to, value for a Transfer), block number, log index, transaction hash, removed flag, and network context metadata for Base (chain IDs 8453 and 84532, OP Stack protocol family). Also includes warnings if logs are caller-supplied and not independently verified.

## Request schema (JSON Schema)

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

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "replay": false,
  "result": {
   "warnings": [
    "Supplied logs are not independently verified."
   ],
   "service_id": "base_event_log_decode",
   "analysis_json": "{\"address\":\"0x0000000000000000000000000000000000000001\",\"args\":{\"from\":\"0x0000000000000000000000000000000000000001\",\"to\":\"0x0000000000000000000000000000000000000002\",\"value\":\"100\"},\"block_number\":1,\"event_name\":\"Transfer\",\"log_index\":0,\"network_context\":{\"accepted_chain_ids\":[\"8453\",\"84532\"],\"deposit_transaction_type\":\"0x7e\",\"fee_model\":\"L2 execution plus caller-supplied L1 data/operator components\",\"protocol_family\":\"OP Stack\"},\"removed\":false,\"transaction_hash\":\"0x1111111111111111111111111111111111111111111111111111111111111111\"}",
   "evidence_scope": "caller_supplied_data",
   "analyzed_network": "base"
  },
  "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": "base_event_log_decode",
   "executionId": "example-execution",
   "startedAtMs": 0,
   "amountAtomic": "10000",
   "resultSha256": "0eff082e3b6078abc126260c0ee9d8583e92645d3e05feaaadccf6d659cde91b",
   "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-base-event-log-decoder-12e5e251/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)