# quartermaster.surewhynot.app Transaction Decoder

> quartermaster.surewhynot.app Transaction Decoder is a paid API for AI agents from quartermaster.surewhynot.app, paid per call via x402, $0.003/call, status unknown (last checked 2026-09-14).

Decodes a Base blockchain transaction's calldata into a human-readable function name and arguments, recognizing ERC-20 transfer/approve and EIP-3009 transferWithAuthorization used in x402 settlements.

## Facts

- Endpoint: GET https://quartermaster.surewhynot.app/v1/tx-decode
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/quartermaster-surewhynot-app-transaction-decoder-ae08200d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_-gpXvAff3TLNL7ffGlgh3

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 quartermaster-surewhynot-app-transaction-decoder-ae08200d
```

Example prompt: Can you decode this Base transaction for me and tell me what function was called and with what arguments? The hash is 0x3a1b2c4d5e6f7a8b9c0d1e2f3a4b5c6d7e8f9a0b1c2d3e4f5a6b7c8d9e0f1a2b.

## When to prefer this

Use this endpoint when you need to understand what a specific Base transaction actually did at the calldata level — especially for ERC-20 transfers, approvals, or x402 settlement transactions using EIP-3009 transferWithAuthorization. Prefer this over generic block explorers when you need structured, machine-readable output for programmatic use or when working within an x402 payment workflow.

## Known failure modes

- Transaction hash not found on Base — hash may be for a different chain or not yet confirmed
- Invalid hash format — must be 0x-prefixed 66-character hex string
- Transaction has no calldata (plain ETH transfer) — no function to decode
- Unrecognized function selector — returns raw selector without human-readable decoding
- Network timeout when fetching transaction from Base RPC

## How this service works

Decode a Base transaction's calldata into a human-readable function call and arguments — ERC-20 transfer/approve and the EIP-3009 transferWithAuthorization used by x402 settlements. Recognizes x402 settlement transactions.

## Output

A structured breakdown of the transaction's calldata including the decoded function name (e.g. transfer, approve, transferWithAuthorization), all arguments with their names and values, and a flag indicating whether this is recognized as an x402 settlement transaction.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "hash"
     ],
     "properties": {
      "hash": {
       "type": "string",
       "pattern": "^0x[0-9a-fA-F]{64}$",
       "description": "Base transaction hash to decode"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/quartermaster-surewhynot-app-transaction-decoder-ae08200d/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from quartermaster.surewhynot.app](https://www.zero.xyz/host/quartermaster.surewhynot.app/llms.txt)