My MCP Server Kept Crashing. Here's the Error Recovery Pattern That Saved It.

I spent three days wondering why my MCP server would just... stop. No crash logs. No error messages. Clients connected fine, then after a few hours, every tool call returned silence. Turns out the Model Context Protocol (MCP) spec doesn't force you to handle errors — it assumes you will. But the reference implementations are minimal. Your server starts healthy, then bit by bit, things go wrong. A network blip. A malformed tool argument. An external API timeout. And suddenly your AI agent is staring at a blank response. Here's the pattern I ended up with. It's not clever. It just works. The Fix Start with a wrapper around your tool handlers. Every MCP server framework has some kind of tool registration — this works for the official Python SDK, the TypeScript SDK, and most community frameworks: from mcp.server import Server from mcp.types import ErrorData , INTERNAL_ERROR , INVALID_PARAMS import traceback import json class ResilientMCPServer ( Server ): """ An MCP server that doesn ' t silently die. """ async def call_tool ( self , name : str , arguments : dict ): try : result = await super (). call_tool ( name , arguments ) return result except ( ConnectionError , TimeoutError ) as e : # Network-level issues — reconnect and retry self . _reconnect () return self . _error_response ( f " Connection lost while executing { name } : { e } " ) except ValueError as e : # Bad arguments from the client — tell them clearly return self . _error_response ( f " Invalid arguments for { name } : { e } " , code = INVALID_PARAMS ) except Exception as e : # Everything else — log, don't crash traceback . print_exc () return self . _error_response ( f " Tool { name } failed: { e } " , code = INTERNAL_ERROR ) def _error_response ( self , message : str , code : int = INTERNAL_ERROR ): return { " content " : [{ " type " : " text " , " text " : f " ERROR: { message } " }], " isError " : True } def _reconnect ( self ): """ Reset transport layer without restarting the server. """ # Your recon