MetaMask MCP

Instructions

Implementation Reference

• src/tools/get-balance.ts:35-45 (handler)

  The handler function that executes the get-token-balance tool logic by calling wagmi's getBalance with the provided address and token.

  execute: async (args) => {
    const result = await getBalance(wagmiConfig, args);
    return {
      content: [
        {
          type: "text",
          text: JSONStringify(result),
        },
      ],
    };
  },

• src/tools/get-balance.ts:31-34 (schema)

  Input schema definition using Zod for the get-token-balance tool parameters: address and token addresses.

  parameters: z.object({
    address: Address.describe("Address to get balance for."),
    token: Address.describe("ERC-20 token address to get balance for."),
  }),

• src/tools/get-balance.ts:28-46 (registration)

  Direct registration of the get-token-balance tool on the FastMCP server instance, including name, description, schema, and handler.

  server.addTool({
    name: "get-token-balance",
    description: "Get token balance of an address.",
    parameters: z.object({
      address: Address.describe("Address to get balance for."),
      token: Address.describe("ERC-20 token address to get balance for."),
    }),
    execute: async (args) => {
      const result = await getBalance(wagmiConfig, args);
      return {
        content: [
          {
            type: "text",
            text: JSONStringify(result),
          },
        ],
      };
    },
  });

• src/tools/register-tools.ts:41-41 (registration)

  Intermediate registration call that invokes the registration of get-token-balance (among get-balance tools).

  registerGetBalanceTools(server, wagmiConfig);

• src/index.ts:15-15 (registration)

  Top-level registration of all tools, which chains to including the get-token-balance tool.

  registerTools(server, wagmiConfig);