How to Add a Second Key to an Existing Keybind

Open the Controls Menu

Press the key that opens the game menu (by default Esc), then click Options... and choose Controls.... You will see the standard list of vanilla keybinds on the left and any modded keybinds below or in their own category. Find the action you want to give an extra key to — for example, Jump, Sneak, or Inventory.

Assign the Extra Binding

Click the keybind entry once so it enters listening mode, then press the new key you want to add. With Multi Key Bindings installed, the entry does not simply overwrite the old key — it accepts an additional assignment. The controls list will show the action with more than one key listed next to it. Repeat the click-and-press step for each extra key you want on that same action. If you make a mistake, click the entry again and press the key you want to remove, or use the reset control to clear that action back to its default.

Confirm and Test

Click Done to save, then return to the game and try both keys. Each one should trigger the same action. This works identically for modded keybinds, so you can give a mod's ability two different keys without editing config files.