[Bug]: Cannot find module '@mongodb-js/saslprep'

[marclou]

Version

mongodb-mcp-server@0.3.0
Node 24.3.0

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

Cannot find module '@mongodb-js/saslprep' when running npx -y mongodb-mcp-server on node 24.3.0

[github-actions]

Thanks for opening this issue. The ticket MCP-180 was created for internal tracking.

[kmruiz]

Hi @marclou ,

can you provide more information on the environment where you are running the MCP Server?

• Can you provide the host OS? Are you running on a Linux Distro/Windows/OSX?
• Are you using a Docker container?
• Can you go to a temporary directory and run npm i @mongodb-js/saslprep? Later delete any node_modules folder created.

@mongodb-js/saslprep is a security library used by the MongoDB Driver. Does installing the driver work for you?

Thanks!

[marclou]

sure

• MacOS
• Nope, just a NextJS project
• I did install saslprep successfully but I still get "Error: Cannot find module '@mongodb-js/saslprep'" when enabling the MCP server

[kmruiz]

Do I guess right that your NextJS application can connect to MongoDB fine and run queries?

@nirinchev , @himanshusinghs , @blva . I'll be off for a few days, can you take the lead on this one? To make sure it's not a generalised issue.

[marclou]

Correct

Do I guess right that your NextJS application can connect to MongoDB fine and run queries?

Correct, no issues with that!

[gagik]

I'm unable to recreate this but a couple things worth confirming for this:

1. Running npm cache verify to make sure the npm cache isn't in a weird state.
2. npm list -g --depth=0 Check that you do not have any globally installed packages that can conflict with this (i.e. an old mongodb or other MongoDB dependent tool. --depth=1 might be useful too)
3. Check that the directory you're running from doesn't have any NPM dependencies that could affect this or ideally isn't a Node project directory at all (i.e. with npm list mongodb-mcp-server and npm list mongodb).
4. where npm, where npx and where node all point to the same installation of Node/NPM.

If nothing suspicious is caught from there, you can try installing with npm i --g mongodb-mcp-server. Though I'd expect it to fail similarly. Going down a Docker route should hopefully unblock you otherwise but we'd definitely want to resolve this issue if it persists.

[github-actions]

The corresponding JIRA ticket has been automatically closed.