In the left panel you can click on the tuplets symbol. You instantly get a triplet when inputting notes. This is much quicker than using value, than ;, than 3, than enter.
You cannot choose a key command for the tuplets symbol in the left panel, like with grace note. Why is that?

I did a search on the subject; Daniel wrote:
The “simplified” tuplet function in the toolbox is simply to create a triplet. The plan there is that you will be able to click and hold on the button to see a menu (in a similar way to the tools in e.g. Photoshop, if you’re familiar with that application) that would allow you to choose between a handful of common ratios, though I don’t think that assigning a shortcut to each of those would save you more than a couple of keystrokes compared to using the popover in any case

Still it would be helpfull to have a shortcut for the present tuplet function in the toolbox, because it creates a triplet instantly, and that’s what most people need most of the time, I think.

Check out this post for a workaround:

It used to work perfectly. I’ve ditched it after I had to redo all of my key commands in 1.0.10. Not sure if it still works, but worth trying.

The reason is, that the key command to create the triplet from the note input panel is a specialised version of the generic ‘create tuplet’ command, with an extra parameter which you can’t currently assign via the visual key commands editor.

Yes, that workaround, editing the .json file manually, should still work exactly as described. We will make this kind of customisation easier in future of course, but can’t promise a timescale for that right now.

Sorry that I keep on about it, but I do not get it.
The tuplet function in the toolbox is no key command, but accessed through a mouse-click. I guess some way or another it’s not yet possible to assign a keycommand to this existing function because it has an extra parameter?

Editing the .json file must be done in wordpad?
Thanks in advance.

Editing the .json file should be done in a plain text editor. There are many excellent text editors available: on Windows, I always liked scITE. On Mac, because I’m an old man I use BBEdit, but I understand that all the cool kids are using Sublime Text these days.

Your assessment that you cannot assign a key command directly in the editor because the command has an extra parameter is quite correct.

It works! Pressing “y” now creates a triplet of the chosen notevalue.
editing keycommands_en.json.PNG
Saves me a lot of effort