# Onchain Transaction Explainer (Base/EVM)

> Onchain Transaction Explainer (Base/EVM) is a paid API for AI agents from 138-197-15-135.sslip.io, paid per call via x402, $0.015/call, status unknown (last checked 2026-10-31).

Fetches and explains a blockchain transaction in plain English, returning structured facts and a human-readable summary.

## Facts

- Endpoint: GET https://138-197-15-135.sslip.io/v1/ai/tx-explain?utm_source=zero.xyz
- Price: $0.015/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-31
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/onchain-transaction-explainer-base-evm-eae6c8ee
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_3jZbAa0j9NagFvOw7ZEhO

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 onchain-transaction-explainer-base-evm-eae6c8ee
```

Example prompt: Can you explain what happened in transaction 0xe3ee160e… on Base — who sent what to whom, whether it succeeded, and roughly what the fee was?

## When to prefer this

Use this endpoint when you need a human-readable explanation of a specific onchain transaction — especially on Base or other EVM chains — including decoded method calls, token transfers, success status, and fee estimates. It is particularly well-suited for x402 payment transactions. Prefer it over raw RPC calls when you want structured facts plus a natural-language summary in one step.

## Known failure modes

- Invalid or malformed transaction hash returns an error or null fields
- Transaction hash not found on the specified chain returns null summary
- Unsupported chain value returns an error
- Network or RPC timeout results in a failed lookup
- Payment not included or rejected by x402 protocol returns HTTP 402

## How this service works

Plain-English explanation of any transaction on Base, Ethereum, Arbitrum or Optimism: what happened, who sent what to whom (decoded token transfers with amounts and symbols), the method called, fee paid, and success/failure. Returns a summary plus the structured facts it is based on.

## Output

Returns a JSON object with the original transaction hash, chain name, a structured 'facts' object (method signature, status, list of token transfers), and a concise plain-English summary describing the participants, action, outcome, and approximate fee.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "queryParams"
   ],
   "properties": {
    "queryParams": {
     "type": "object",
     "required": [
      "hash"
     ],
     "properties": {
      "hash": {
       "type": "string",
       "description": "Transaction hash"
      },
      "chain": {
       "type": "string",
       "description": "Chain: base (default), ethereum, arbitrum, optimism"
      }
     }
    }
   }
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "json"
    },
    "example": {
     "type": "object",
     "required": [],
     "properties": {
      "hash": {
       "type": [
        "string",
        "null"
       ]
      },
      "chain": {
       "type": [
        "string",
        "null"
       ]
      },
      "facts": {
       "type": [
        "object",
        "null"
       ]
      },
      "summary": {
       "type": [
        "string",
        "null"
       ]
      }
     }
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "hash": "0x…",
  "chain": "base",
  "facts": {
   "method": "0xe3ee160e",
   "status": "success",
   "transfers": []
  },
  "summary": "Wallet 0xa729… sent 0.0009 USDC to 0x1074… (an x402 payment), settled by a facilitator. Succeeded; fee ~$0.0001."
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/onchain-transaction-explainer-base-evm-eae6c8ee/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from 138-197-15-135.sslip.io](https://www.zero.xyz/host/138-197-15-135.sslip.io/llms.txt)