refactor: Introduce ServerManager and related tools for improved MCP server management

Author: zandko

index.ts

@@ -9,4 +9,7 @@ import { WebSocketConnector } from './src/connectors/websocket.js'
 import { Logger, logger } from './src/logging.js'
 import { MCPSession } from './src/session.js'
 
+export { BaseAdapter, LangChainAdapter } from './src/adapters/index.js'
+export { ServerManager } from './src/managers/server_manager.js'
+
 export { BaseConnector, HttpConnector, loadConfigFile, Logger, logger, MCPAgent, MCPClient, MCPSession, StdioConnector, WebSocketConnector }

package.json

@@ -44,7 +44,7 @@
     "registry": "https://registry.npmjs.org"
   },
   "scripts": {
-    "build": "rm -rf dist && tsc && shx chmod +x dist/*.js",
+    "build": "rm -rf dist && tsc",
     "watch": "tsc --watch",
     "start": "node dist/index.js",
     "prepublishOnly": "pnpm run build",
@@ -60,7 +60,9 @@
     "@langchain/core": "0.3.54",
     "@modelcontextprotocol/sdk": "1.11.0",
     "eventsource": "^3.0.6",
+    "fastembed": "^1.14.4",
     "langchain": "^0.3.24",
+    "lodash-es": "^4.17.21",
     "uuid": "^11.1.0",
     "winston": "^3.17.0",
     "ws": "^8.18.2",
@@ -69,6 +71,7 @@
   },
   "devDependencies": {
     "@antfu/eslint-config": "^4.13.0",
+    "@types/lodash-es": "^4.17.12",
     "@types/ws": "^8.18.1",
     "eslint": "^9.26.0",
     "eslint-plugin-format": "^1.0.1",

pnpm-lock.yaml

@@ -102,7 +102,7 @@ export class LangChainAdapter extends BaseAdapter<StructuredToolInterface> {
           return parseMcpToolResult(result)
         }
         catch (err: any) {
-          logger.error(`Error executing MCP tool: ${err}`)
+          logger.error(`Error executing MCP tool: ${err.message}`)
           return `Error executing MCP tool: ${String(err)}`
         }
       },

src/adapters/langchain_adapter.ts

@@ -1,3 +1,2 @@
 export { BaseAgent } from './base.js'
 export { MCPAgent } from './mcp_agent.js'
-export { ServerManager } from './server_manager.js'

src/agents/index.ts

@@ -6,8 +6,8 @@ import type { StructuredToolInterface, ToolInterface } from '@langchain/core/too
 import type { AgentFinish, AgentStep } from 'langchain/agents'
 import type { MCPClient } from '../client.js'
 import type { BaseConnector } from '../connectors/base.js'
+import type { ServerManager } from '../managers/server_manager.js'
 import type { MCPSession } from '../session.js'
-import type { ServerManager } from './server_manager.js'
 import {
   AIMessage,
   HumanMessage,
@@ -107,7 +107,7 @@ export class MCPAgent {
       await this.serverManager.initialize()
 
       // Get server management tools
-      const managementTools = await this.serverManager.getServerManagementTools()
+      const managementTools = this.serverManager.tools
       this.tools = managementTools
       logger.info(
         `🔧 Server manager mode active with ${managementTools.length} management tools`,
@@ -302,7 +302,7 @@ export class MCPAgent {
 
       for (let stepNum = 0; stepNum < steps; stepNum++) {
         if (this.useServerManager && this.serverManager) {
-          const currentTools = await this.serverManager.getAllTools()
+          const currentTools = this.serverManager.tools
           const currentToolNames = new Set(currentTools.map(t => t.name))
           const existingToolNames = new Set(this.tools.map(t => t.name))
 
@@ -322,7 +322,7 @@ export class MCPAgent {
           }
         }
 
-        logger.info(`🔍 Step ${stepNum + 1}/${steps}`)
+        logger.info(`👣 Step ${stepNum + 1}/${steps}`)
 
         try {
           logger.debug('Starting agent step execution')

src/agents/mcp_agent.ts

@@ -95,10 +95,13 @@ export class MCPClient {
     return this.sessions
   }
 
-  public getSession(serverName: string): MCPSession {
+  public getSession(serverName: string): MCPSession | null {
     const session = this.sessions[serverName]
+    // if (!session) {
+    //   throw new Error(`No session exists for server '${serverName}'`)
+    // }
     if (!session) {
-      throw new Error(`No session exists for server '${serverName}'`)
+      return null
     }
     return session
   }

src/agents/server_manager.ts

@@ -11,6 +11,7 @@ interface LoggerOptions {
   level?: LogLevel
   console?: boolean
   file?: string
+  format?: 'minimal' | 'detailed' | 'emoji'
 }
 
 const DEFAULT_LOGGER_NAME = 'mcp-use'
@@ -26,12 +27,21 @@ function resolveLevel(env: string | undefined): LogLevel {
   }
 }
 
-const defaultFormatter = printf(({ level, message, label, timestamp }) => {
+const minimalFormatter = printf(({ level, message, label, timestamp }) => {
+  return `${timestamp} [${label}] ${level}: ${message}`
+})
+
+const detailedFormatter = printf(({ level, message, label, timestamp }) => {
+  return `${timestamp} [${label}] ${level.toUpperCase()}: ${message}`
+})
+
+const emojiFormatter = printf(({ level, message, label, timestamp }) => {
   return `${timestamp} [${label}] ${level.toUpperCase()}: ${message}`
 })
 
 export class Logger {
   private static instances: Record<string, WinstonLogger> = {}
+  private static currentFormat: 'minimal' | 'detailed' | 'emoji' = 'minimal'
 
   public static get(name: string = DEFAULT_LOGGER_NAME): WinstonLogger {
     if (!this.instances[name]) {
@@ -41,8 +51,8 @@ export class Logger {
           colorize(),
           splat(),
           label({ label: name }),
-          timestamp(),
-          defaultFormatter,
+          timestamp({ format: 'HH:mm:ss' }),
+          this.getFormatter(),
         ),
         transports: [],
       })
@@ -51,10 +61,24 @@ export class Logger {
     return this.instances[name]
   }
 
+  private static getFormatter() {
+    switch (this.currentFormat) {
+      case 'minimal':
+        return minimalFormatter
+      case 'detailed':
+        return detailedFormatter
+      case 'emoji':
+        return emojiFormatter
+      default:
+        return minimalFormatter
+    }
+  }
+
   public static configure(options: LoggerOptions = {}): void {
-    const { level, console = true, file } = options
+    const { level, console = true, file, format = 'minimal' } = options
     const resolvedLevel = level ?? resolveLevel(process.env.DEBUG)
 
+    this.currentFormat = format
     const root = this.get()
 
     root.level = resolvedLevel
@@ -72,6 +96,18 @@ export class Logger {
       }
       root.add(new transports.File({ filename: file }))
     }
+
+    // Update all existing loggers with new format
+    Object.values(this.instances).forEach((logger) => {
+      logger.level = resolvedLevel
+      logger.format = combine(
+        colorize(),
+        splat(),
+        label({ label: DEFAULT_LOGGER_NAME }),
+        timestamp({ format: 'HH:mm:ss' }),
+        this.getFormatter(),
+      )
+    })
   }
 
   public static setDebug(enabled: boolean | 0 | 1 | 2): void {
@@ -87,6 +123,11 @@ export class Logger {
     })
     process.env.DEBUG = enabled ? (enabled === true ? '2' : String(enabled)) : '0'
   }
+
+  public static setFormat(format: 'minimal' | 'detailed' | 'emoji'): void {
+    this.currentFormat = format
+    this.configure({ format })
+  }
 }
 
 Logger.configure()

src/client.ts

@@ -0,0 +1,2 @@
+export * from './server_manager.js'
+export * from './tools/index.js'