@Arg @Quoted String 
If you want to parse an argument with quoted content including spaces and special characters, use the @Quoted annotation.
java
@Command(name = "mute")
public class MuteCommand {
    @Execute
    void mute(
        @Context CommandSender sender, 
        @Arg Player target, 
        @Arg @Quoted String reason
    ) {
        // [...] mute implementation
        sender.message(ChatUtil.color("&cPlayer &7" + target.getName() + " &chas been muted! Reason: &7" + reason));
    }
}Here is an example of the /mute command usage:
/mute <player> <reason...>
Input
/mute Rollczi "Spamming and harassment"Output
Player Rollczi has been muted! Reason: Spamming and harassment Norbert Dejlich
 Norbert Dejlich