check-balance
Check the ETH balance of an Ethereum address using the MCP Etherscan Server. Enter a valid 0x format address to retrieve current balance information.
Instructions
Check the ETH balance of an Ethereum address
Input Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| address | Yes | Ethereum address (0x format) |
Implementation Reference
- src/server.ts:169-185 (handler)Executes the "check-balance" tool: validates input address, fetches balance from EtherscanService, formats and returns the response.
if (name === "check-balance") { try { const { address } = AddressSchema.parse(args); const balance = await etherscanService.getAddressBalance(address); const response = `Address: ${balance.address}\nBalance: ${balance.balanceInEth} ETH`; 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; } } - Core implementation fetching ETH balance using ethers.EtherscanProvider.getBalance and formatting to ETH.
async getAddressBalance(address: string): Promise<{ address: string; balanceInWei: bigint; balanceInEth: string; }> { try { // Validate the address const validAddress = ethers.getAddress(address); // Get balance in Wei const balanceInWei = await this.provider.getBalance(validAddress); // Convert to ETH const balanceInEth = ethers.formatEther(balanceInWei); return { address: validAddress, balanceInWei, balanceInEth }; } catch (error) { if (error instanceof Error) { throw new Error(`Failed to get balance: ${error.message}`); } throw error; } } - src/server.ts:66-80 (registration)Registers the "check-balance" tool in the listTools response with name, description, and input schema.
{ name: "check-balance", description: "Check the ETH balance of an Ethereum address", inputSchema: { type: "object", properties: { address: { type: "string", description: "Ethereum address (0x format)", pattern: "^0x[a-fA-F0-9]{40}$", }, }, required: ["address"], }, }, - src/server.ts:36-40 (schema)Zod schema for validating the Ethereum address input used in the check-balance handler.
const AddressSchema = z.object({ address: z .string() .regex(/^0x[a-fA-F0-9]{40}$/, "Invalid Ethereum address format"), });