MCP Etherscan Server

Instructions

Implementation Reference

• src/server.ts:187-224 (handler)

  Handler for the 'get-transactions' tool: validates input with TransactionHistorySchema, calls etherscanService.getTransactionHistory, formats transactions into a readable text response.
  if (name === "get-transactions") { try { const { address, limit } = TransactionHistorySchema.parse(args); const transactions = await etherscanService.getTransactionHistory( address, limit ); const formattedTransactions = transactions .map((tx) => { const date = new Date(tx.timestamp * 1000).toLocaleString(); return ( `Block ${tx.blockNumber} (${date}):\n` + `Hash: ${tx.hash}\n` + `From: ${tx.from}\n` + `To: ${tx.to}\n` + `Value: ${tx.value} ETH\n` + `---` ); }) .join("\n"); const response = transactions.length > 0 ? `Recent transactions for ${address}:\n\n${formattedTransactions}` : `No transactions found for ${address}`; return { content: [{ type: "text", text: response }], }; } catch (error) { if (error instanceof z.ZodError) { throw new Error( `Invalid input: ${error.errors.map((e) => e.message).join(", ")}` ); } throw error; } }
• src/server.ts:42-47 (schema)

  Zod schema for validating input parameters (address and optional limit) for the get-transactions tool.
  const TransactionHistorySchema = z.object({ address: z .string() .regex(/^0x[a-fA-F0-9]{40}$/, "Invalid Ethereum address format"), limit: z.number().min(1).max(100).optional(), });
• src/server.ts:81-101 (registration)

  Tool registration in listTools response, defining name, description, and input schema.
  { name: "get-transactions", description: "Get recent transactions for an Ethereum address", inputSchema: { type: "object", properties: { address: { type: "string", description: "Ethereum address (0x format)", pattern: "^0x[a-fA-F0-9]{40}$", }, limit: { type: "number", description: "Number of transactions to return (max 100)", minimum: 1, maximum: 100, }, }, required: ["address"], }, },
• src/services/etherscanService.ts:64-95 (helper)

  EtherscanService.getTransactionHistory: fetches transaction list from Etherscan API via fetch, validates address, formats into Transaction interface objects.
  async getTransactionHistory(address: string, limit: number = 10): Promise<Transaction[]> { try { // Validate the address const validAddress = ethers.getAddress(address); // Get transactions directly from Etherscan API const result = await fetch( `https://api.etherscan.io/api?module=account&action=txlist&address=${validAddress}&startblock=0&endblock=99999999&page=1&offset=${limit}&sort=desc&apikey=${this.provider.apiKey}` ); const data = await result.json(); if (data.status !== "1" || !data.result) { throw new Error(data.message || "Failed to fetch transactions"); } // Format the results return data.result.slice(0, limit).map((tx: any) => ({ hash: tx.hash, from: tx.from, to: tx.to || 'Contract Creation', value: ethers.formatEther(tx.value), timestamp: parseInt(tx.timeStamp) || 0, blockNumber: parseInt(tx.blockNumber) || 0 })); } catch (error) { if (error instanceof Error) { throw new Error(`Failed to get transaction history: ${error.message}`); } throw error; } }
• src/services/etherscanService.ts:3-10 (helper)

  TypeScript interface defining the structure of a Transaction object returned by getTransactionHistory.
  export interface Transaction { hash: string; from: string; to: string; value: string; timestamp: number; blockNumber: number; }