[Bug]: Switching Connection When Connection String Is Not Initially Specified

[BrunoIzagu]

Version

mongo-mcp:
type: stdio
command: npx
args:
- -y
- "mongodb-mcp-server"

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

I am experiencing a problem when attempting to switch the connection if the connection string is not specified from the beginning. The server initializes correctly and is able to perform the first connection successfully. However, after that, it is not possible to change or switch the connection.

[mongo-mcp][connect] Tool call failed MCP error -32602: MCP error -32602: Tool connect not found

[GaurabAryal]

Hi @BrunoIzagu, thank you for your feedback! I wanted to understand a couple of things as we are potentially considering deprecating the switch-connection tool.

1. Are you OK with pasting your connection string directly in your LLM chat? Are you passing connection string to local instances where you don't have sensitive credentials?
2. Are there alternate/more secure ways where we could help you switch connection? One potential solution could be allowing you to define all your connection strings at the config level. This way you do not have to pass sensitive creds in your LLM chat.

Will let @nirinchev follow up here on debugging the issue you're experiencing!

[nirinchev]

Can you clarify how/why the model is trying to invoke the connect tool? Asking mostly because beyond the first connection, we update the connect tool name and description and send out a tool update notification, so it's kind of surprising that the model is trying to invoke connect at that point.