Misleading error message when wrong prefix is entered

[yytan25]

I tried to add a person named Charlie and 'tag' him as 'friends' using the prefix t/ (due to the behaviour of AB3) as follows:

The command fails as expected, but the error message differed slightly from what i expected:

Maybe the logic of the program thought that the name was mistakenly input as "Charlie t/friends", but there should be a check in place when a user inputs an erroneous tag. This will help to enhance the user experience.