Fix resource leak issues and add security warning for tokens

Co-authored-by: TheR1D <16740832+TheR1D@users.noreply.github.com>

README.md

@@ -351,13 +351,16 @@ MCP_ENABLED=true
       "command": "npx",
       "args": ["-y", "@modelcontextprotocol/server-github"],
       "env": {
-        "GITHUB_PERSONAL_ACCESS_TOKEN": "your_github_token"
+        "GITHUB_PERSONAL_ACCESS_TOKEN": "${GITHUB_TOKEN}"
       }
     }
   }
 }
 ```
 
+**Security Note:** It's recommended to use environment variables for sensitive data like tokens instead of hardcoding them in the configuration file. The example above shows using `${GITHUB_TOKEN}` which should be set as an environment variable.
+
+
 Once configured, ShellGPT will automatically connect to the MCP servers and make their tools available to the LLM. The LLM can then use these tools just like regular functions:
 
 ```shell

sgpt/mcp_client.py

@@ -136,15 +136,19 @@ class MCPClient:
         if not self.enabled or self._initialized:
             return
 
+        loop = None
         try:
             # Run async initialization in event loop
             loop = asyncio.new_event_loop()
             asyncio.set_event_loop(loop)
             loop.run_until_complete(self._initialize_async())
-            loop.close()
         except Exception:
             # If initialization fails, disable MCP
+            # Silently fail to avoid breaking existing functionality
             self.enabled = False
+        finally:
+            if loop:
+                loop.close()
 
     def get_tools_schemas(self) -> List[Dict[str, Any]]:
         """Get OpenAI-compatible function schemas for all MCP tools."""
@@ -211,16 +215,19 @@ class MCPClient:
         server_name, tool_name = parts
 
         # Run async call in event loop
+        loop = None
         try:
             loop = asyncio.new_event_loop()
             asyncio.set_event_loop(loop)
             result = loop.run_until_complete(
                 self._call_tool_async(server_name, tool_name, arguments)
             )
-            loop.close()
             return result
         except Exception as e:
             return f"Error: {str(e)}"
+        finally:
+            if loop:
+                loop.close()
 
     def cleanup(self) -> None:
         """Clean up MCP client connections."""