EVM MCP Server

Instructions

Implementation Reference

• src/index.ts:848-875 (handler)

  Inline asynchronous handler function for the 'net_version' MCP tool. It calls makeRPCCall('net_version') to fetch the network ID via RPC, formats the result using formatResponse, and returns it in the expected MCP content structure. Handles errors by returning an error message.

  server.tool("net_version", "Returns the current network id", {}, async () => {
    try {
      const result = await makeRPCCall("net_version");
  
      return {
        content: [
          {
            type: "text",
            text: formatResponse(
              {
                network_id: result,
              },
              "Network Version",
            ),
          },
        ],
      };
    } catch (error: any) {
      return {
        content: [
          {
            type: "text",
            text: `Error: ${error.message}`,
          },
        ],
      };
    }
  });

• src/index.ts:848-875 (registration)

  Registration of the 'net_version' tool on the MCP server using server.tool(). Includes tool name, description 'Returns the current network id', empty input schema {}, and the inline handler function.

  server.tool("net_version", "Returns the current network id", {}, async () => {
    try {
      const result = await makeRPCCall("net_version");
  
      return {
        content: [
          {
            type: "text",
            text: formatResponse(
              {
                network_id: result,
              },
              "Network Version",
            ),
          },
        ],
      };
    } catch (error: any) {
      return {
        content: [
          {
            type: "text",
            text: `Error: ${error.message}`,
          },
        ],
      };
    }
  });

• src/index.ts:89-96 (helper)

  makeRPCCall utility function that wraps ethers.JsonRpcProvider.send() to perform RPC calls. Directly used in the net_version handler to invoke the 'net_version' RPC method.

  async function makeRPCCall(method: string, params: any[] = []): Promise<any> {
    try {
      const result = await provider.send(method, params);
      return result;
    } catch (error: any) {
      throw new Error(`RPC call failed: ${error.message}`);
    }
  }

• src/index.ts:32-57 (helper)

  formatResponse utility function that converts data objects into formatted Markdown strings for tool responses. Used in net_version handler to format {network_id: result} with title 'Network Version'.

  function formatResponse(data: any, title: string): string {
    let result = `**${title}**\n\n`;
  
    if (typeof data === "object" && data !== null) {
      if (Array.isArray(data)) {
        // Handle arrays
        result += `**Count:** ${data.length}\n\n`;
        data.forEach((item, index) => {
          result += `**${index + 1}.**\n`;
          if (typeof item === "object" && item !== null) {
            result += formatObject(item, "  ");
          } else {
            result += `  ${item}\n`;
          }
          result += "\n";
        });
      } else {
        // Handle objects
        result += formatObject(data, "");
      }
    } else {
      result += `${data}\n`;
    }
  
    return result;
  }