# Ethereum Function Signature Lookup

> Ethereum Function Signature Lookup is a paid API for AI agents from pyfile-agent.taile3ff35.ts.net:10000, paid per call via x402, $0.003/call, status unknown (last checked 2026-09-15).

Resolves a 4-byte Ethereum ABI function selector to its human-readable function signature

## Facts

- Endpoint: GET https://pyfile-agent.taile3ff35.ts.net:10000/data/abi
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/ethereum-function-signature-lookup-80fd337c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_XAXYOpnz5FM5TbIhUoNND

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 ethereum-function-signature-lookup-80fd337c
```

Example prompt: What Ethereum function is being called by the selector 0xa9059cbb? Can you look up its human-readable signature?

## When to prefer this

Use this endpoint when you need to decode a raw 4-byte Ethereum function selector into its human-readable function signature, especially during smart contract auditing, transaction analysis, or calldata inspection. Prefer this over full ABI parsing when you only have the selector and not the full contract ABI.

## Known failure modes

- Unknown selector not found in signature database returns empty or 404 response
- Malformed selector (not 4 bytes / invalid hex) returns an error
- Selector with multiple known signatures may return ambiguous results
- Network timeout or service unavailability returns 5xx error

## How this service works

Ethereum function signature lookup. ?selector=0xa9059cbb

## Output

Returns the human-readable Ethereum ABI function signature (e.g. 'transfer(address,uint256)') corresponding to the provided 4-byte hex selector, allowing developers and agents to decode and understand smart contract calldata without access to the original ABI.

## 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": {
      "selector": {
       "type": "string"
      }
     }
    }
   }
  },
  "output": {
   "type": "object"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/ethereum-function-signature-lookup-80fd337c/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from pyfile-agent.taile3ff35.ts.net:10000](https://www.zero.xyz/host/pyfile-agent.taile3ff35.ts.net%3A10000/llms.txt)