We don’t support syncing at the moment. The import and export capabilities are just a one-time push/pull to or from GitHub. You can use git to push and pull the code too from the Glitch console (available under Advanced options from the top left project info menu) which doesn’t require permissions in Glitch. Syncing is something we want to support going forward. For now, you have to get creative with GitHub webhooks to add such a capability to your projects, which sounds like it’s unlikely to be suitable for your use-case.