MCP Server Boilerplate

/* eslint-disable max-lines-per-function */ import { setTimeout } from 'node:timers/promises'; import { zodToJsonSchema } from 'zod-to-json-schema'; import { loggingContext, sendProgressNotification } from '@/core/server'; import { ToolBuilder, ToolContext, ToolInputSchema, ToolResult, } from '@/tools/types'; import packageJson from '../../../package.json'; import { StreamingInput, StreamingInputSchema, StreamingOutput } from './types'; /** * Streaming tool that simulates real-time data streaming * * BUT it seems not working as expected. Just leave it here for now. */ async function* executeStreaming( input: StreamingInput, context: ToolContext ): AsyncGenerator<ToolResult & { data?: StreamingOutput }> { loggingContext.setContextValue('tool', 'streaming'); const startTime = Date.now(); const progressToken = context.progressToken; try { loggingContext.log('info', 'Starting streaming', { data: { input, progressToken }, }); const validatedInput = StreamingInputSchema.parse(input); const { dataType, count, intervalMs } = validatedInput; const dataPoints: Array<{ timestamp: string; index: number; value: unknown; }> = []; // Send initial progress if (context.server) { await sendProgressNotification(context.server, { progressToken, progress: 0, total: count, message: `Starting ${dataType} streaming (${count} points, ${intervalMs}ms intervals)`, }); } // Generate and stream data points for (let i = 1; i <= count; i++) { // Generate data point based on type const dataPoint = generateDataPoint(dataType, i); const timestamp = new Date().toISOString(); dataPoints.push({ timestamp, index: i, value: dataPoint, }); // Send progress update if (context.server) { await sendProgressNotification(context.server, { progressToken, progress: i, total: count, message: `Streamed ${i}/${count} ${dataType} data points`, }); } const executionTime = Date.now() - startTime; const output: StreamingOutput = { dataType, count: validatedInput.count, intervalMs, totalDuration: executionTime, dataPoints: [...dataPoints], // Create a copy for each yield completedAt: timestamp, }; // Yield intermediate result for streaming yield { success: true, data: output, executionTime, timestamp, metadata: { toolVersion: packageJson.version, dataType, currentPoint: i, totalPoints: count, streamingEnabled: true, isIntermediate: i < count, }, }; loggingContext.log('debug', `Streaming data point ${i} generated`, { data: { dataPoint, timestamp }, }); // Wait for the specified interval (except for the last iteration) if (i < count) { await setTimeout(intervalMs); } } // Final completion notification if (context.server) { await sendProgressNotification(context.server, { progressToken, progress: count, total: count, message: `${dataType} streaming completed successfully`, }); } const totalExecutionTime = Date.now() - startTime; const finalOutput: StreamingOutput = { dataType, count, intervalMs, totalDuration: totalExecutionTime, dataPoints, completedAt: new Date().toISOString(), }; loggingContext.log('info', 'Streaming completed', { data: { totalExecutionTime, pointsGenerated: dataPoints.length }, }); // Final yield with completion yield { success: true, data: finalOutput, executionTime: totalExecutionTime, timestamp: new Date().toISOString(), metadata: { toolVersion: packageJson.version, dataType, totalPoints: count, streamingEnabled: true, isIntermediate: false, completed: true, }, }; } catch (error) { const executionTime = Date.now() - startTime; const errorMessage = error instanceof Error ? error.message : 'Unknown error occurred'; // Send error notification if (context.server) { await sendProgressNotification(context.server, { progressToken, progress: -1, total: input.count, message: `Streaming failed: ${errorMessage}`, }); } loggingContext.log('error', 'Streaming failed', { data: { error: errorMessage, input, executionTime }, }); yield { success: false, error: errorMessage, executionTime, timestamp: new Date().toISOString(), metadata: { toolVersion: packageJson.version, inputValidation: 'failed', }, }; } } /** * Generate sample data point based on data type */ function generateDataPoint(dataType: string, index: number): unknown { switch (dataType) { case 'metrics': return { cpu: Math.round(Math.random() * 100 * 100) / 100, memory: Math.round((50 + Math.random() * 40) * 100) / 100, disk: Math.round((20 + Math.random() * 30) * 100) / 100, network: Math.round(Math.random() * 1000 * 100) / 100, }; case 'stock_prices': return { symbol: 'DEMO', price: Math.round((100 + Math.random() * 50) * 100) / 100, volume: Math.floor(Math.random() * 10000), change: Math.round((Math.random() * 10 - 5) * 100) / 100, }; case 'sensor_data': return { temperature: Math.round((20 + Math.random() * 15) * 100) / 100, humidity: Math.round((40 + Math.random() * 40) * 100) / 100, pressure: Math.round((1000 + Math.random() * 50) * 100) / 100, light: Math.floor(Math.random() * 1000), }; case 'custom': default: return { id: `data_${index}`, value: Math.round(Math.random() * 1000), category: ['A', 'B', 'C'][Math.floor(Math.random() * 3)], active: Math.random() > 0.5, }; } } /** * Create and export the streaming tool */ export const streamingTool = new ToolBuilder<StreamingInput, StreamingOutput>( 'streaming' ) .description('Simulate real-time streaming data with live updates') .inputSchema(zodToJsonSchema(StreamingInputSchema) as typeof ToolInputSchema) .examples([ { input: { dataType: 'metrics', count: 5, intervalMs: 1000 }, output: { success: true, data: { dataType: 'metrics', count: 5, intervalMs: 1000, totalDuration: 5000, dataPoints: [ { timestamp: '2024-01-15T10:30:00.000Z', index: 1, value: { cpu: 45.2, memory: 67.8, disk: 35.1, network: 234.5 }, }, ], completedAt: '2024-01-15T10:30:05.000Z', }, }, description: 'Stream system metrics data in real-time', }, { input: { dataType: 'stock_prices', count: 3, intervalMs: 2000 }, output: { success: true, data: { dataType: 'stock_prices', count: 3, intervalMs: 2000, totalDuration: 6000, dataPoints: [ { timestamp: '2024-01-15T10:30:00.000Z', index: 1, value: { symbol: 'DEMO', price: 125.45, volume: 5678, change: 2.3, }, }, ], completedAt: '2024-01-15T10:30:06.000Z', }, }, description: 'Stream stock price data with live updates', }, ]) .tags(['streaming', 'real-time', 'data']) .version(packageJson.version) .timeout(30000) // 30 second timeout .streamingImplementation(executeStreaming) .build();