# EVM Transaction Preflight for Agents

> EVM Transaction Preflight for Agents is a paid API for AI agents from x402-market-intel-mcp.mtree.workers.dev, paid per call via x402, $0.15/call, status unknown (last checked 2026-09-16).

Decodes and analyzes an EVM transaction (target, value, calldata) to flag approvals, transfer selectors, and bytecode risk, returning a sign/avoid/manual-review verdict before the agent submits it on-chain.

## Facts

- Endpoint: POST https://x402-market-intel-mcp.mtree.workers.dev/v1/x402/tx_preflight_for_agents
- Price: $0.15/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-16
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/evm-transaction-preflight-for-agents-286c6c4f
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_8ZjLvgQISjq7c3nvLFZH5

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 evm-transaction-preflight-for-agents-286c6c4f -d '<json body>'
```

Example prompt: Before I submit this transaction, run a preflight check on it: the target contract is 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48, value is 0, and the calldata is 0x095ea7b3000000000000000000000000someSpenderAddress000000000000000000000000ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff — tell me if I should sign, avoid, or manually review it.

## When to prefer this

Use this endpoint when an AI agent needs to autonomously evaluate an EVM transaction before signing or submitting it on-chain — especially when detecting token approvals, unlimited allowances, or suspicious transfer selectors matters. Prefer this over generic contract explorers when you need a machine-readable sign/avoid/manual-review verdict packaged for agent consumption, and when paying per-call via x402 on Base is acceptable.

## Known failure modes

- Malformed or missing calldata returns a decoding error
- Unverified or non-contract target address may limit bytecode analysis
- Network issues reaching the EVM node cause probe failures
- Invalid transaction structure returns a 400-level validation error
- Payment not confirmed via x402 results in 402 response blocking the call

## How this service works

EVM transaction preflight modeled on top-earning tx simulator/explainer endpoints: decode target/value/data shape, probe bytecode, flag approvals/transfer selectors, and return sign/avoid/manual-review verdict. Price 0.15 USDC on Base via x402. Demo: https://x402-market-intel-mcp.mtree.workers.dev/demo/tx_preflight_for_agents. Contact: https://x402-market-intel-mcp.mtree.workers.dev/contact.

## Output

A verdict of sign, avoid, or manual-review along with a decoded breakdown of the transaction shape (target, value, data), identified selectors (e.g. ERC-20 approve or transfer), bytecode probe results, and specific risk flags that informed the decision.

## 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",
    "bodyType",
    "body"
   ],
   "properties": {
    "body": {
     "type": "object",
     "properties": {
      "to": {
       "type": "string"
      },
      "tx": {
       "type": "object"
      },
      "data": {
       "type": "string"
      },
      "chain": {
       "type": "string"
      },
      "value": {
       "type": "string"
      },
      "rpc_url": {
       "type": "string"
      }
     }
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    }
   },
   "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/evm-transaction-preflight-for-agents-286c6c4f/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402-market-intel-mcp.mtree.workers.dev](https://www.zero.xyz/host/x402-market-intel-mcp.mtree.workers.dev/llms.txt)