# Base Contract Creation Transaction Inspector

> Base Contract Creation Transaction Inspector is a paid API for AI agents from signalharness.ai, paid per call via x402, $0.015/call, status unknown (last checked 2026-09-15).

Analyzes a Base blockchain contract creation transaction's raw JSON to extract creator, nonce, init code details, expected deployment address, gas, and network context without executing or deploying anything.

## Facts

- Endpoint: POST https://signalharness.ai/api/agent/services/base_contract_creation_inspect/invoke
- Price: $0.015/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/base-contract-creation-transaction-inspector-4b274000
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_-qCFzUQ-UHAGVO7X5WOv5

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-creation-transaction-inspector-4b274000 -d '<json body>'
```

Example prompt: Can you inspect this Base contract creation transaction JSON and tell me who the creator is, what address the contract will deploy to, and what the init code hash is?

## When to prefer this

Use this endpoint when you need to statically analyze a Base (or Base Sepolia) contract creation transaction before broadcasting it — for example to predict deployment address, audit init code, or verify gas and nonce. It is ideal for pre-flight checks in deployment pipelines. Prefer this over on-chain simulation tools when you want fast, cheap, offline analysis without executing any code or making on-chain calls.

## Known failure modes

- Malformed or invalid transaction JSON returns an error
- Missing creator address means expected deployment address cannot be computed (warned in output)
- Chain ID not in accepted list (8453 or 84532) may cause incorrect network context
- Very large init code may be rejected if request_json exceeds 65536 character limit
- Non-contract-creation transactions (e.g. ETH transfers) may produce misleading or empty analysis

## How this service works

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## Output

Returns a JSON analysis object including the creator address, expected contract address (if derivable), init code byte length and hash, gas limit, nonce, transaction value, and OP Stack network context (accepted chain IDs, fee model, deposit transaction type). Also includes a list of warnings (e.g. if the expected address cannot be computed). The response notes that this analysis covers only caller-supplied data and does not prove deployment, runtime bytecode, or contract 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 prove deployment, runtime bytecode, or contract safety."
   ],
   "service_id": "base_contract_creation_inspect",
   "analysis_json": "{\"creator\":\"0x0000000000000000000000000000000000000001\",\"expected_address\":null,\"gas_limit\":\"21000\",\"init_code_bytes\":68,\"init_code_hash\":\"0x53893ee34a7f44a17cb623aa779750e71b27d6a76064cb515b6c5c42a4a973f7\",\"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\"},\"nonce\":\"1\",\"value\":\"0\",\"warnings\":[\"expected address requires a supplied creator and nonce derivation\"]}",
   "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_creation_inspect",
   "executionId": "example-execution",
   "startedAtMs": 0,
   "amountAtomic": "15000",
   "resultSha256": "0befe26045f694a37ef5313f50373c55fe3f53c962bc47332319ce61d8b13e8d",
   "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-creation-transaction-inspector-4b274000/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)