Cheat Mode and Give Mode

What cheat mode changes

Normally clicking an item in the JEI list opens its recipe. Cheat Mode changes that single behaviour: JEI gives you the item instead of showing you how to make it. The config description says it plainly, "Give items instead of showing the recipe". Everything else about JEI stays the same.

It is meant for testing a build, laying out a creative world, or checking that a machine works before you commit to farming its inputs. On a server you will only get items if the server actually lets you, so treat cheat mode as a convenience in your own worlds rather than something you can rely on anywhere.

Turning it on without opening the config

Three actions live under the JEI (Cheat Mode) category in Options, Controls:

• Toggle Cheat Mode flips it on and off mid-game.
• Cheat 1 Stack grabs a full stack of whatever is under the cursor.
• Cheat 1 Item grabs a single one.

There is also Toggle Cheat Mode bound under JEI (Hovering With Mouse Over Config Button), which does the same thing while you are pointing at JEI's own config button, so you can switch without leaving the screen you are on.

Give mode: where the item lands

Give Mode decides what happens to an item the moment JEI hands it to you. Set to inventory, the item goes straight into your inventory. The other setting puts it on your cursor instead, so you pick it up and place it yourself.

The difference matters more than it sounds. Dropping items straight into the inventory is faster when you are stocking up on many different things. Picking them up on the cursor is better when you are filling one specific slot in a machine, because the item never has to be found again in a full inventory.

A note on debug mode

The config also has Debug Mode, and its own description warns that it is "only useful for JEI developers" — it adds test ingredients and fake recipes to the list. If your item list suddenly contains items that do not exist in the game, that is the setting to check.