systemprompt-mcp-server

/** * @file MCP Logging tool implementation * @module handlers/tools/logging * * @remarks * This module implements the MCP logging tool that sends log messages * to the MCP client for debugging and monitoring purposes. This follows * the MCP specification for client-side logging, NOT server-side logging. * * The MCP logging feature allows servers to send log messages to clients * at various levels (debug, info, warning, error). These logs appear in * the client's console or logging interface, not in the server's logs. * * @see {@link https://modelcontextprotocol.io/specification/2025-06-18/server/utilities/logging | MCP Logging} */ import type { CallToolResult } from '@modelcontextprotocol/sdk/types.js'; import type { ToolHandlerContext } from './types.js'; import { getMCPHandlerInstance } from '../../server/mcp.js'; /** * Handles the MCP logging tool requests. * * @remarks * This tool sends log messages to the MCP client using the MCP SDK's * logging functionality. The logs appear in the client's console or * logging interface, allowing for debugging and monitoring of server * operations from the client side. * * According to the MCP specification, servers can send logging messages * to clients as notifications. This is different from server-side logging * and is specifically designed for client visibility into server operations. * * The tool accepts the following parameters: * - `level`: The log level (debug, info, warning, error) * - `message`: The message to send to the client * - `data`: Optional additional data to include (as JSON) * * @param args - Tool arguments containing level, message, and optional data * @param context - MCP tool context with session and auth info * @returns Success result confirming the log was sent to the client * * @example * ```json * { * "level": "info", * "message": "Reddit search completed successfully", * "data": { "query": "typescript", "results": 10 } * } * ``` */ export async function handleLogging( args: { level: 'debug' | 'info' | 'warning' | 'error'; message: string; data?: any; }, context: ToolHandlerContext ): Promise<CallToolResult> { const { level, message, data } = args; const { sessionId } = context; // Validate log level const validLevels = ['debug', 'info', 'warning', 'error']; if (!validLevels.includes(level)) { throw new Error(`Invalid log level: ${level}. Must be one of: ${validLevels.join(', ')}`); } // Validate message if (!message || typeof message !== 'string') { throw new Error('Message is required and must be a string'); } // Get the MCP handler instance to access the server const handler = getMCPHandlerInstance(); if (!handler) { throw new Error('MCP handler not initialized'); } // Get the server instance for this session const server = handler.getServerForSession(sessionId!); if (!server) { throw new Error(`No active server found for session: ${sessionId}`); } // Prepare the log data const logData = data ? ` | Data: ${JSON.stringify(data)}` : ''; const fullMessage = `[${level.toUpperCase()}] ${message}${logData}`; // Send log message to the client using the MCP server's notification system // The MCP SDK will handle sending this as a logging notification to the client try { // According to MCP spec, logging is sent as notifications to the client // The server.sendLoggingMessage method sends logs to the connected client await server.notification({ method: 'notifications/message', params: { level: level, message: fullMessage, data: { timestamp: new Date().toISOString(), sessionId, ...(data && { additionalData: data }) } } }); } catch (error) { // If we can't send to client, at least log locally for debugging console.error(`Failed to send log to MCP client: ${error}`); } return { content: [ { type: 'text', text: `Log message sent to client at ${level} level: ${message}`, }, ], }; }