EVM Contract Source and ABI Fetcher (v3.1)

This tool fetches verified Solidity source code and ABI for a given EVM contract address and chain ID, detecting common proxy patterns and preferring implementation contract source when available. It supports Ethereum mainnet (1), Base (8453 via Basescan), Optimism (10), Arbitrum (42161), and Polygon (137), typically via Sourcify first with a fallback to Etherscan-style explorer APIs. It accepts chain_id (integer) and contract_address (string) as inputs and does not require any additional JSON payload parameters. The worker must use only the provided inputs, normalize any contract and proxy metadata as needed, and emit a single final JSON object that strictly validates against the system-provided structured output schema.