MCP initialization issue for servers using customUserVars

[shirsho-dutt]

Hello Danny,

As per this feature: #7980, it seems LibreChat now supports customUserVars.

I was trying to add GitHub's official MCP server: https://github.com/github/github-mcp-server?tab=readme-ov-file, using the PAT approach where user passes their individual PAT token like this:

github-mcp:
    type: streamable-http
    url: "https://api.githubcopilot.com/mcp/"
    headers:
      Authorization: "{{PAT_TOKEN}}"
    customUserVars:
      PAT_TOKEN:
        title: "GitHub PAT Token"
        description: "GitHub Personal Access Token"
    chatMenu: false

But this does not work and I am getting error as Authorization failed when LibreChat server starts up.

But if I hardcode my PAT:

github-mcp:
    type: streamable-http
    url: "https://api.githubcopilot.com/mcp/"
    headers:
      Authorization: "<redacted_token>"
    chatMenu: false

this works as at startup the token value exists.

Could you please tell me how to use the customUserVars so that the server startup issue is avoided and the user can enter their PAT tokens from the UI to use the MCP server??

[danny-avila]

Unfortunately, this feature doesn't meet your use case without some way of specifying a server-startup specific value. Maybe that is in order @dustinhealy ?

[shirsho-dutt]

Hello @danny-avila and @dustinhealy ,
The main problem today is that all the latest official MCPs like Github, Atlassian etc. all have OAuth built in them and the OAuth is needed to fetch the toolset or list of tools as well.
As per Librechat's implementation of MCP and OAuth, we first need to connect to the MCP server on startup and get the list of tools and then OAuth can happen while calling the tools.
If any MCP needs OAuth to startup and fetch the tools list, Librechat breaks as the user can't authenticate as per user for that. This seems because you guys fetch the tool list at startup from the YAML config file.
Are you planning to do something to connect to an MCP server and fetch tool-list from the UI after startup of Librechat or on the fly? Because this is becoming a big blocker to do OAuth or do per user authentication for most official MCP servers when we host Librechat on the cloud premise?

Some official MCP servers with the above issue:

1. Github: https://github.com/github/github-mcp-server
2. Atlassian MCP: https://community.atlassian.com/forums/Atlassian-Platform-articles/Atlassian-Remote-MCP-Server-beta-now-available-for-desktop/ba-p/3022084

[danny-avila]

Are you planning to do something to connect to an MCP server and fetch tool-list from the UI after startup of Librechat or on the fly?

Yeah we are actively working on that, we need to complete some other pieces required for that first, to ensure it is secure.

[yusufcemalcelebi]

This is also blocking using linear MCP on librechat
https://linear.app/docs/mcp

[shirsho-dutt]

With 0.8.0-rc releases all startup disabling options have been introduced and everything works.