After you authorize Multi-Tool the first time, there is an information message whenever you open the tool that says, "You have already authorized this tool but may need to authorize again if permissions have changed or your permission has been revoked in another way."

screenshot of canvas info alert that reads You have already authorized this tool but may need to authorize again if permissions have changed or your permission has been revoked in another way.

This message will not interfere with any of the functionality of the Multi-Tool.  It is simply a notice for you that if your permissions change or your authorization is deleted, that the tool will ask you to authorize again before using it.