# EVM Calldata Encoder with Risk Flags

> EVM Calldata Encoder with Risk Flags is a paid API for AI agents from evm-canon-base.onrender.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-15).

Encodes EVM calldata from a named function signature and human-readable arguments, returning deterministic risk flags without signing or broadcasting

## Facts

- Endpoint: POST https://evm-canon-base.onrender.com/encode
- 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/evm-calldata-encoder-with-risk-flags-143f294e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_iGoxv8RIqD1hQlh5sM1Kx

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-calldata-encoder-with-risk-flags-143f294e -d '<json body>'
```

Example prompt: Can you encode the calldata for calling the `transfer(address,uint256)` function with recipient `0xAbCd...1234` and amount `1000000000000000000` (1 ETH in wei), and tell me if there are any risk flags I should know about before I sign anything?

## When to prefer this

Use this endpoint when you need to construct EVM transaction calldata from human-readable function names and arguments before signing, especially when you want deterministic risk flags evaluated upfront. Prefer this over raw ABI encoding libraries when you need an auditable, server-side encoding step with built-in safety checks, or when orchestrating agent workflows that must validate transaction intent before committing.

## Known failure modes

- Invalid function signature or ABI mismatch returns a 400 error
- Malformed or out-of-range argument values cause encoding failure
- Unknown function name with no ABI provided results in an error
- Payment not included or insufficient USDC causes a 402 response
- Argument count mismatch with function signature returns descriptive error

## How this service works

Build EVM calldata from a named function and human arguments, with deterministic risk flags; never signs or broadcasts

## Output

Returns ABI-encoded calldata as a hex string ready to be used as transaction data, along with deterministic risk flags (e.g. unlimited allowance, high-risk function detected) based on the function and arguments provided. No signing or broadcasting occurs.

## 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",
     "required": [
      "args"
     ],
     "properties": {
      "args": {
       "type": "object",
       "description": "arguments keyed by parameter name"
      },
      "chain": {
       "description": "chain name, alias or numeric chainId"
      },
      "token": {
       "type": "string",
       "description": "symbol or contract address"
      },
      "value": {
       "type": "string",
       "description": "native value in wei"
      },
      "function": {
       "type": "string",
       "description": "name or full signature (generic route only)"
      }
     }
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST",
      "PUT",
      "PATCH"
     ],
     "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-calldata-encoder-with-risk-flags-143f294e/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from evm-canon-base.onrender.com](https://www.zero.xyz/host/evm-canon-base.onrender.com/llms.txt)