This extension for Fallen London periodically checks your 'Messages' tab for social invitations.
This unofficial extension for Fallen London periodically checks your 'Messages' tab behind the scenes for new invitations for social actions. It checks every time you log in (or refresh the page) and at intervals thereafter. Once you've seen an invitation, it'll remember this.
The extension only checks for notifications that require a response, so you won't be alerted when invitations you've sent are accepted (or when Time, the Healer comes visiting, etc.).
v. 1.2.2 has some minor fixes, removing unused dependencies.