# LION Keyless Transaction Receipt Decoder (x402)

> LION Keyless Transaction Receipt Decoder (x402) is a paid API for AI agents from lion-x402.lionmaster-operations.workers.dev, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-15).

Fetches and decodes a blockchain transaction receipt on Base, returning human-readable calldata including function signature and parameters, paid per-call in USDC via x402.

## Facts

- Endpoint: GET https://lion-x402.lionmaster-operations.workers.dev/api/x402/tx-receipt-decoded-json
- 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/lion-keyless-transaction-receipt-decoder-x402-a51ea773
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_kIjB4RM3LLIhv6eRucOBv

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 lion-keyless-transaction-receipt-decoder-x402-a51ea773
```

Example prompt: Can you fetch and decode the transaction receipt for 0xabc123...def on Base — I want to see what function was called and what the parameters were, without needing an API key?

## When to prefer this

Choose this endpoint when you need to decode Base (EVM) transaction receipts into human-readable function calls without managing API keys or subscriptions — especially useful for AI agents that pay per-call via x402 USDC micropayments and need to understand what a specific transaction actually did on-chain.

## Known failure modes

- Invalid or non-existent transaction hash returns error or empty receipt
- Payment not completed via x402 returns 402 Payment Required
- Unsupported JSON-RPC method returns error
- Transaction calldata cannot be decoded (e.g. no matching ABI) returns low confidence or raw hex
- Network congestion causes delayed response
- Batch size exceeds 10 requests returns rejection

## How this service works

Keyless off-chain and on-chain data for AI agents. No API key, no signup - payment is the only gate. Pay-per-call in USDC on Base via x402.

## Output

A JSON object containing the raw transaction receipt (to, from, value, status, gasUsed, blockNumber) plus decoded calldata showing the function signature and its parameter values, along with a confidence score and asset identifier.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "tx"
     ],
     "properties": {
      "tx": {
       "type": "string",
       "description": "Base tx hash 0x..."
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "tx": "0x...",
  "network": "eip155:8453",
  "receipt": {
   "to": "0x...",
   "from": "0x...",
   "value": "0x0",
   "status": "0x1",
   "gasUsed": "0x...",
   "blockNumber": "0x..."
  },
  "asset_id": "LION_TX_RECEIPT_DECODED_001",
  "confidence": 0.9,
  "decoded_calldata": {
   "sig": "transfer(address,uint256)",
   "params": [
    "0x...",
    "1000000000000000000"
   ]
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/lion-keyless-transaction-receipt-decoder-x402-a51ea773/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from lion-x402.lionmaster-operations.workers.dev](https://www.zero.xyz/host/lion-x402.lionmaster-operations.workers.dev/llms.txt)