web3-mcp-server

Instructions

Implementation Reference

• src/tools/ReadContract.ts:14-28 (handler)

  The main handler function `readContract` that executes the tool logic using viem client to read from the contract.

  export const readContract = async (options: ReadContractOptions) => {
    const { contractAddress, chainId, abi, functionName, args } = options;
  
    const chain = getChainById(chainId);
    const client = createClient(chain);
  
    const result = await client.readContract({
      address: contractAddress as `0x${string}`,
      abi: JSON.parse(abi),
      functionName,
      args,
    });
  
    return result;
  };

• src/tools/ReadContract.ts:5-11 (schema)

  Zod schema defining the input parameters for the read_contract tool.

  export const ReadContractSchema = z.object({
    contractAddress: z.string().startsWith("0x"),
    chainId: z.number(),
    abi: z.string(),
    functionName: z.string(),
    args: z.array(z.string()),
  });

• src/index.ts:40-44 (registration)

  Registration of the 'read_contract' tool in the list of tools returned by ListToolsRequest.

  {
    name: "read_contract",
    description: "Read a value from a contract",
    inputSchema: z.toJSONSchema(ReadContractSchema),
  },

• src/index.ts:104-120 (registration)

  Dispatcher case in CallToolRequest handler that parses args, calls readContract, and formats the response.

  case "read_contract": {
    const args = ReadContractSchema.parse(request.params.arguments);
    const result = await readContract(args);
  
    return {
      content: [
        {
          type: "text",
          text: JSON.stringify(result, (_, value) =>
            typeof value === "bigint" ? value.toString() : value
          ),
          description:
            "The result JSON formatted of the contract function call",
        },
      ],
    };
  }