helloTool

Implementation Reference

• src/tools/helloTool.ts:16-39 (handler)

  The asynchronous handler function that executes the helloTool logic, processing the optional message input and returning a text response or error.

  async ({ message }) => {
    try {
      const responseMessage = message ? `You said: ${message}` : "Hello, World!";
      
      return {
        content: [
          {
            type: "text",
            text: responseMessage
          }
        ]
      };
    } catch (error) {
      return {
        content: [
          {
            type: "text",
            text: `Error in hello tool: ${error instanceof Error ? error.message : String(error)}`
          }
        ],
        isError: true
      };
    }
  }

• src/tools/helloTool.ts:13-15 (schema)

  The input schema for helloTool, defining an optional 'message' string parameter using Zod.

  {
    message: z.string().optional().describe("Message to echo back. If not provided, returns a default greeting.")
  },

• src/tools/helloTool.ts:11-40 (registration)

  The server.tool() invocation that registers the 'helloTool' with its name, input schema, and handler function.

  server.tool(
    "helloTool",
    {
      message: z.string().optional().describe("Message to echo back. If not provided, returns a default greeting.")
    },
    async ({ message }) => {
      try {
        const responseMessage = message ? `You said: ${message}` : "Hello, World!";
        
        return {
          content: [
            {
              type: "text",
              text: responseMessage
            }
          ]
        };
      } catch (error) {
        return {
          content: [
            {
              type: "text",
              text: `Error in hello tool: ${error instanceof Error ? error.message : String(error)}`
            }
          ],
          isError: true
        };
      }
    }
  );

• src/tools/helloTool.ts:7-43 (helper)

  The exported registerHelloTool function that sets up and registers the helloTool on the MCP server instance.

  export function registerHelloTool(server: McpServer): void {
    console.error('Registering Hello World tool...');
    
    // Tool to echo a message or respond with "Hello, World!"
    server.tool(
      "helloTool",
      {
        message: z.string().optional().describe("Message to echo back. If not provided, returns a default greeting.")
      },
      async ({ message }) => {
        try {
          const responseMessage = message ? `You said: ${message}` : "Hello, World!";
          
          return {
            content: [
              {
                type: "text",
                text: responseMessage
              }
            ]
          };
        } catch (error) {
          return {
            content: [
              {
                type: "text",
                text: `Error in hello tool: ${error instanceof Error ? error.message : String(error)}`
              }
            ],
            isError: true
          };
        }
      }
    );
    
    console.error('Hello World tool registered successfully');
  }

• src/index.ts:21-21 (registration)

  The call to registerHelloTool during the main server initialization in the entry point file.

  registerHelloTool(server);