/goop [MESSAGE]something ...
If you are familiar with oS: on success keyword, you'll notice that there is no oF: on fail, preventing you from telling players that they dont have the correct item or something. This fixes that.
To use this feature, one must take a look at the file plugins/Gunging_Ootilities_Plugin/fail-messages.yml
In there, you can write the name of a message, 'MESSAGE', and use it anytime you are calling a GooP command, any command. For example, lets use GooP Testinventory ~ goop testinventory <player> <slot> {item}
Basically, having your message names in place, you may choose which is told to the player when the testinventory command fails. From there, you just specify which to send with square brackets before the subcommand:
/goop [NotEnoughMangoes]testinventory cocopad m CONSUMABLE MANGO
Notice that it parses PAPI placeholders.
Naming a fail message exactly like the command, in lowercase (for example "testinventory" or "consumeitem"), will make it default and you wont need to include it with brackets ~ it will display automatically.
To maintain legacy compatibility,"VaultLowBalance" keyword is automatically linked to Goop Vault Charge. This is also displayed when a CustomStructure has a vault cost and the player cant afford to use it.