# Base Chain Transaction Simulator

> Base Chain Transaction Simulator is a paid API for AI agents from kr-x402-mvp.kgy5612.workers.dev, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-31).

Simulates one or more Ethereum/Base transactions dry-run style, returning gas usage, token transfers, approvals, balance changes, and a SAFE/UNSAFE verdict before any real funds move.

## Facts

- Endpoint: GET https://kr-x402-mvp.kgy5612.workers.dev/api/chain/simulate?utm_source=zero.xyz
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-31
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/base-chain-transaction-simulator-1097a3d9
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_YAZjgISs54RdpIhSm9CAs

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 base-chain-transaction-simulator-1097a3d9
```

Example prompt: Before I actually send it, simulate this Base transaction for me: sender 0xe4be4d0bd82d8e68203deff81f79ede0529f2617 calling 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 with calldata 0xa9059cbb... and 0 ETH — tell me if it's safe, how much gas it'll use, and what tokens move.

## When to prefer this

Use this endpoint when an AI agent needs to verify the safety and outcome of a Base chain transaction before executing it with real funds. Ideal for DeFi agents, wallet assistants, and autonomous trading bots that must confirm gas cost, token flow, and revert risk prior to signing. Prefer over on-chain execution when a dry-run preview is needed, and over generic RPC eth_call when you want decoded human-readable output including transfer breakdowns, verdicts, and USD fee estimates.

## Known failure modes

- Invalid address format returns 400 validation error
- Malformed calldata hex returns parse error
- Simulation of a reverted call returns success:false with revert_reason populated
- Insufficient balance in simulated state causes revert
- Network timeout if Base RPC is congested
- Payment failure via x402 if USDC balance insufficient

## How this service works

Pay-per-call crypto microdata for trading/onchain AI agents via x402 (USDC on Base): Base gas, token risk, balances, multi-venue prices, Hyperliquid book/funding, kimchi premium. No API keys.

## Output

Returns a JSON object with: overall success boolean and SAFE_TO_SEND/UNSAFE verdict, decoded function name, gas used and fee in ETH and USD, list of token transfers (from/to/amount/symbol), approval events, per-address balance changes (sender_changes and balance_changes), revert reason if applicable, block number, and suggested next API endpoints for follow-up.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "to": {
       "type": "string",
       "pattern": "^0x[0-9a-fA-F]{40}$",
       "examples": [
        "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"
       ],
       "description": "Target contract or recipient"
      },
      "data": {
       "type": "string",
       "pattern": "^0x([0-9a-fA-F]{2})*$",
       "description": "Calldata (default 0x)"
      },
      "from": {
       "type": "string",
       "pattern": "^0x[0-9a-fA-F]{40}$",
       "examples": [
        "0xe4be4d0bd82d8e68203deff81f79ede0529f2617"
       ],
       "description": "Sender (signer) address"
      },
      "calls": {
       "type": "string",
       "description": "URL-encoded JSON array of up to 5 {to,data,value_eth|value} run in order from the same sender"
      },
      "value_eth": {
       "type": "string",
       "examples": [
        "0.01"
       ],
       "description": "ETH to send, decimal (default 0)"
      }
     },
     "additionalProperties": false
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "from": "0xe4be4d0bd82d8e68203deff81f79ede0529f2617",
  "next": [
   "/crypto/base-gas",
   "/crypto/tx-status?hash="
  ],
  "block": 53272234,
  "calls": [
   {
    "to": "0x833589fcd6edb6e08f4c7c32d4f71b54bda02913",
    "index": 0,
    "success": true,
    "function": "transfer(address,uint256)",
    "gas_used": 45047,
    "revert_reason": null
   }
  ],
  "chain": "base",
  "flags": [],
  "fee_eth": 5e-7,
  "fee_usd": 0.0019,
  "success": true,
  "summary": "1 call succeeds; sender sends 0.001 USDC",
  "verdict": "SAFE_TO_SEND",
  "approvals": [],
  "transfers": [
   {
    "to": "0xa587d73489f8f09d1975f1ddbb1c61c93e8fa9d7",
    "from": "0xe4be4d0bd82d8e68203deff81f79ede0529f2617",
    "token": "0x833589fcd6edb6e08f4c7c32d4f71b54bda02913",
    "amount": 0.001,
    "symbol": "USDC"
   }
  ],
  "gas_used_total": 45047,
  "sender_changes": {
   "USDC": -0.001
  },
  "balance_changes": {
   "0xa587d73489f8f09d1975f1ddbb1c61c93e8fa9d7": {
    "USDC": 0.001
   },
   "0xe4be4d0bd82d8e68203deff81f79ede0529f2617": {
    "USDC": -0.001
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/base-chain-transaction-simulator-1097a3d9/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from kr-x402-mvp.kgy5612.workers.dev](https://www.zero.xyz/host/kr-x402-mvp.kgy5612.workers.dev/llms.txt)