MetaMask MCP

import type { Config } from "@wagmi/core"; import type { FastMCP } from "fastmcp"; import { readContract } from "@wagmi/core"; import { Abi, Address } from "abitype/zod"; import { TransactionExecutionError } from "viem"; import { z } from "zod"; export function registerReadContractTools(server: FastMCP, wagmiConfig: Config): void { server.addTool({ name: "read-contract", description: "Call a read-only function on a contract, and returning the response.", parameters: z.object({ abi: Abi.describe("The contract's ABI."), address: Address.describe("The contract's address."), functionName: z.string().describe("Function to call on the contract."), args: z.unknown().array().optional().describe("Arguments to pass when calling the contract."), chainId: z.coerce.number().optional().describe("ID of chain to use when fetching data."), }), execute: async (args) => { try { const result = await readContract(wagmiConfig, args); return { content: [ { type: "text", text: `${result}`, }, ], }; } catch (error) { if (error instanceof TransactionExecutionError) { return { content: [ { type: "text", text: error.cause.message, }, ], }; } return { content: [ { type: "text", text: (error as Error).message, }, ], }; } }, }); };