MCP Wait Timer Server

Instructions

Implementation Reference

• src/index.ts:21-39 (handler)

  The handler function that executes the 'wait' tool logic: logs start, waits using setTimeout for the specified duration in seconds, logs finish, and returns success content. Handles errors similarly.

  async function waitHandler(args: z.infer<typeof waitInputSchema>): Promise<CallToolResult> {
    const { duration_seconds } = args;
    try {
      console.error(`[mcp-wait-timer] Waiting for ${duration_seconds} seconds...`);
      await new Promise(resolve => setTimeout(resolve, duration_seconds * 1000));
      console.error(`[mcp-wait-timer] Wait finished.`);
      return {
        isError: false,
        content: [{ type: 'text', text: `Successfully waited for ${duration_seconds} seconds.` }],
      };
    } catch (error: any) {
      console.error(`[mcp-wait-timer] Error during wait: ${error.message}`);
      // Ensure error responses also conform to CallToolResult
      return {
        isError: true,
        content: [{ type: 'text', text: `Error waiting: ${error.message}` }],
      };
    }
  }

• src/index.ts:16-19 (schema)

  Zod schema definition for input validation of the 'wait' tool, defining duration_seconds as a positive number.

  const waitInputSchemaShape = {
    duration_seconds: z.coerce.number().positive().describe('The number of seconds to wait'), // Use coerce.number()
  };
  const waitInputSchema = z.object(waitInputSchemaShape);

• src/index.ts:43-51 (registration)

  Tool registration object defining the 'wait' tool with name, description, and input schema shape.

  const WAIT_TOOL: Tool = {
    name: 'wait',
    description: 'Waits for a specified duration in seconds.',
    inputSchema: {
      type: 'object',
      properties: waitInputSchemaShape,
      required: ['duration_seconds'],
    },
  };

• src/index.ts:63-65 (registration)

  Registers the 'wait' tool (WAIT_TOOL) in the MCP server's list tools response handler.

  server.setRequestHandler(ListToolsRequestSchema, async () => ({
    tools: [WAIT_TOOL],
  }));

• src/index.ts:67-79 (registration)

  Registers the call tool handler that dispatches to waitHandler if tool name is 'wait', including input validation.

  server.setRequestHandler(CallToolRequestSchema, async (request) => {
    if (request.params.name === WAIT_TOOL.name) {
      const parseResult = waitInputSchema.safeParse(request.params.arguments);
      if (!parseResult.success) {
        throw new McpError(
          ErrorCode.InvalidParams,
          `Invalid arguments for tool ${WAIT_TOOL.name}: ${parseResult.error.message}`
        );
      }
      return waitHandler(parseResult.data);
    }
    throw new McpError(ErrorCode.MethodNotFound, `Unknown tool: ${request.params.name}`);
  });