[Bug]: Incorrect logging capability declaration causing connection errors in MCP Inspector #454
Description
Version
0.2.0
App
- Cursor
- Windsurf
- VSCode
- VSCode Insiders
- Claude Desktop
- Other
Affected Models (if applicable)
- Claude 3.5 Sonnet
- Claude 3.7 Sonnet
- GPT-4a
- o4-mini
- Other
Bug Description
The MongoDB MCP Server incorrectly declares logging capability without implementing the required logging functionality, causing connection errors in MCP clients like the MCP Inspector.
Original issue: modelcontextprotocol/inspector#670
Problem
Current behavior:
- MongoDB MCP Server declares "logging": {} capability in initialization response
- Server does NOT implement logging/setLevel method
- Server does NOT emit notifications/message log notifications
- MCP Inspector attempts to call logging/setLevel based on declared capability
- Server returns MethodNotFound error
- Inspector shows connection as "failed" despite successful connection
Expected behavior:
- Server should only declare capabilities it actually implements
- Connection should show as successful when server is working properly
Root Cause
File: src/server.ts:51
// ❌ INCORRECT - declares logging capability without implementing it
this.mcpServer.server.registerCapabilities({
logging: {}, // Should not be declared
resources: { listChanged: true, subscribe: true }
});
Proposed Fix
Remove the logging: {} capability declaration:
// ✅ CORRECT - only declare implemented capabilities
this.mcpServer.server.registerCapabilities({
resources: { listChanged: true, subscribe: true }
});