Read-only factual data about historical Ethereum mainnet contracts. Use when the user asks about a specific contract address, early Ethereum contracts, deployment era, deployer, bytecode, decompiled code, or documented history (what a contract is and is not). Data is non-opinionated and includes runtime bytecode, decompiled code, and editorial history when available. Base URL https://ethereumhistory.com (or set BASE_URL for local/staging).