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Base Nonce Replacement Analyzer
x402
Base Nonce Replacement Analyzer 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 set of Base (OP Stack) transactions to detect nonce gaps, replacement groups, and sequencing anomalies from caller-supplied transaction data.
Price / call$0.015
Success—
StatusUnknown
How this service works
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Output
Returns a structured analysis JSON containing detected nonce gaps, replacement transaction groups, per-transaction metadata (hash, nonce, from address, gas params), the inferred network context (chain IDs, fee model, protocol family), an evidence scope label, any warnings about limitations, and a service receipt with payment confirmation details.
Example use cases
Debugging stuck wallet transactions
“I submitted several transactions from my wallet on Base and some seem stuck or dropped — can you analyze this transaction list for nonce gaps or replacements so I know what went wrong?”
Gas bump replacement detection
“I bumped the gas on a slow transaction and now I'm not sure if the original or the replacement confirmed — analyze these two Base transactions with the same nonce and tell me if one replaced the other.”
Bot transaction sequencing audit
“My trading bot sent a batch of 15 transactions on Base and I need to know if any were out of order or replaced mid-sequence — here's the full transaction JSON for analysis.”
Technical details
Endpoint
POSThttps://signalharness.ai/api/agent/services/base_nonce_replacement_analyze/invokeWhen to prefer
Choose this endpoint when you need to programmatically analyze a set of Base L2 (OP Stack) transactions for nonce sequencing issues, replacement patterns, or gaps — especially when debugging stuck or dropped transactions from wallets or bots. It is well-suited for agent workflows that already have raw transaction metadata and need structured classification without making direct RPC calls. Prefer alternatives that query live chain state if canonical confirmation of replacement is required.
Side effects
- Malformed or non-JSON request_json causes validation failure
- Missing required transaction fields (hash, nonce, from) results in incomplete analysis
- Canonical replacement status cannot be confirmed without on-chain evidence — analysis is limited to caller-supplied data
- Very large transaction sets may hit the 65536-character input limit
- Chain IDs outside Base (8453) or Base Sepolia (84532) may produce unexpected results
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| request_json | string |
Output
Schema · Response
{
"type": "json",
"example": {
"replay": false,
"result": {
"warnings": [
"Canonical replacement status requires chain evidence not inferred here."
],
"service_id": "base_nonce_replacement_analyze",
"analysis_json": "{\"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_gaps\":[],\"replacement_groups\":[],\"transactions\":[{\"from\":\"0x0000000000000000000000000000000000000001\",\"hash\":\"0x1111111111111111111111111111111111111111111111111111111111111111\",\"index\":0,\"max_fee_per_gas\":\"120\",\"nonce\":\"1\"}]}",
"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_nonce_replacement_analyze",
"executionId": "example-execution",
"startedAtMs": 0,
"amountAtomic": "15000",
"resultSha256": "8c7f4d7e9f511cec78ba553c86dbbbdb04e2f6e9886e7054271c663940a52c1f",
"serviceVersion": "1.0.0",
"settlementReference": "0x0000000000000000000000000000000000000000000000000000000000000000"
},
"artifacts": [],
"requestId": "example-request",
"executionId": "example-execution"
}
}Tags
x402
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