User specific MCP sessions

[changkun]

Hi community, I am implementing a MCP server which provides a set of tools and want to make it available in LibreChat and offer user-specific tool discovery.

According to https://www.librechat.ai/docs/configuration/librechat_yaml/object_structure/mcp_servers#headers
I've configured my MCP server as follows:

mcpServers:
  my-tool:
    url: http://mytool/sse
    timeout: 60000  # 1 minute
    headers:
      X-User-Name: "{{LIBRECHAT_USER_USERNAME}}"
      X-User-Email: "{{LIBRECHAT_USER_EMAIL}}"

I'm using https://github.com/mark3labs/mcp-go for building the MCP server.
And making tool availability basd on the user email

	email := r.Header.Get("X-User-Email")
	if email == "" {
		slog.Warn("No X-User-Email header found in request")
		return nil
	}

	// Check if user is authorized
	isAuthorized := isEmailAuthorized(email)

	session := &UserSession{
		id:            email + "-" + uuid.New().String(),
		email:         email,
		notifChannel:  make(chan mcp.JSONRPCNotification, 10),
		isInitialized: false,
		sessionTools:  make(map[string]server.ServerTool),
		isAuthorized:  isAuthorized,
	}

	slog.Info("Created session for user", "email", email, "authorized", isAuthorized, "session_id", session.id)

	// Register session with the server
	if err := a.server.RegisterSession(context.Background(), session); err != nil {
		slog.Error("Failed to register session", "error", err, "email", email)
		return nil
	}

	// Add tools if user is authorized
	if isAuthorized {
		a.addToolsToSession(session)
	}

	return session

However, LibreChat server initializes the MCP server at boot time.

In app level initialization, no user specific headers are provided:

https://github.com/danny-avila/LibreChat/blob/main/packages/api/src/mcp/manager.ts#L63-L64

User specific connections are only done when tool call is initiated.

https://github.com/danny-avila/LibreChat/blob/main/packages/api/src/mcp/manager.ts#L440

How can we get an MCP server connection initializes and offer user specific tool set when a user logged in?