# Base Contract Interaction Summary

> Base Contract Interaction Summary is a paid API for AI agents from signalharness.ai, paid per call via x402, $0.02/call, status unknown (last checked 2026-09-13).

Analyzes a Base blockchain transaction and returns a structured summary of contract calls, token transfers, logs, selectors, and network context

## Facts

- Endpoint: POST https://signalharness.ai/api/agent/services/base_contract_interaction_summary/invoke
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/base-contract-interaction-summary-ae84a446
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_nhv9dYgJZ2LhrLdIXNBh7

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 base-contract-interaction-summary-ae84a446 -d '<json body>'
```

Example prompt: Analyze this Base transaction for me and give me a summary of what contracts were called, how many token transfers happened, and what function selectors were used — here's the transaction JSON: {paste transaction JSON}.

## When to prefer this

Choose this endpoint when you need a fast, structured breakdown of a Base (or Base Sepolia) transaction's on-chain mechanics — contract addresses, selectors, transfers, and logs — without needing full ABI decoding or contract intent inference. It is well-suited for agent workflows that need to audit, log, or route based on what happened in a transaction, and it operates on caller-supplied data so no RPC node access is required.

## Known failure modes

- Malformed or invalid transaction JSON input returns an error
- Transaction data referencing unsupported chains (non-Base) may not be analyzed correctly
- Service explicitly warns it does not infer contract intent or safety — agent must not rely on it for security judgments
- Empty or minimal transaction JSON may yield sparse results with no transfers or logs detected

## 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 analysis object containing the transaction hash, target contract address, list of all contract addresses touched, function selectors called, token transfer count, log count, a flow ledger, call count, and Base/OP Stack network context (accepted chain IDs, fee model, deposit transaction type). Also includes warnings that the service does not infer contract intent or safety.

## 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": [
    "Does not infer contract intent or safety."
   ],
   "service_id": "base_contract_interaction_summary",
   "analysis_json": "{\"call_count\":0,\"contracts\":[\"0x0000000000000000000000000000000000000002\",\"0x0000000000000000000000000000000000000001\"],\"flow\":{\"ledger\":[],\"transfer_count\":0},\"log_count\":1,\"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\"},\"selectors\":[\"0xa9059cbb\"],\"to\":\"0x0000000000000000000000000000000000000002\",\"transaction_hash\":\"0x1111111111111111111111111111111111111111111111111111111111111111\",\"value\":\"0\"}",
   "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_contract_interaction_summary",
   "executionId": "example-execution",
   "startedAtMs": 0,
   "amountAtomic": "20000",
   "resultSha256": "45a7d2a30ca75703865d4ff4d53b4373b8b24514470208d42c54de9bcc155628",
   "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/base-contract-interaction-summary-ae84a446/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)