The description is a little vague and there is plenty of feedback below on the difficulty in understanding the problem being asked. I also had spent a lot of time trying to understand the question rather than figuring out the best logic for it. I suggest adding the sentence below to the description:

"Consider each triplet as a set of rules for how each letter needs to be ordered in the secret string"

Respectfully, I disagree. I solved this kata, albeit poorly and inefficiently.

You are already reducing my suggested description back down to the vague original one which is my original issue. I think you're missing my point as you're an experienced coder or developer and see the forest for the trees while I'm a beginner looking at every single tree and stumbling along the way. If the spirit of kata is to help people learn coding, my suggestions will help beginners learn more quickly with a simple revision. If the spirit is to provide any kind of arbitrary coding challenge, then sure, having hidden tests and finding the true solution in an obfuscated problem is an interesting challenge. But I'm not interested in the latter and I think if you read some of the other feedback you'll see others agree. I didn't expect such pushback for adding a single addex example to the kata.

First I thought I had to take all the numbers together, then add one, then put the all numbers at the end. E.g. '1foobar99' I thought would be '2foobar00' or 'foobar200' because there was no example with numbers not at the end, I was just guessing.

Then I thought I may have to take into account anything that's not a number because I forgot spaces and special characters don't fall under isalpha() and move them around. This burned at least an hour. The comments helped me understand the numbers in between strings do not get "incremented," only the numbers at the end. It's a good problem once I understood it as it was helpful to learn more about formatting, but I spent probably over an hour trying to solve for the wrong solution.

I think for those who have been looking at code for a long time, it's easy to forget how we beginners interpret everything with both a literal and imaginative eye as we don't have a full box of tools so we don't know what's missing from our box.

It's vague and a poor way to explain what's desired. The whole input is a string so you can't just say if the string ends in a string, that's not clear and asks the viewer to guess what it means. The author really means after the last letter or .isalpha() = True THEN the digits after and at the end should be put together and considered a number. The examples provided do a good job of explaining the context the number should be to answer the kata once what I just metioned is already known. The difficulty of the problem is figuring out what it actually is asking. I hope this helps somebody else learning to not waste time with the semantics of a question and keep moving towards their goals.

I'm going to leave it as a non-spoiler because I think it should have been included. This example would have saved me a ton of time in answering the actual question rather than answering what I think the author implied.

'2!.490foo4bar0281701'-> '2!.490foo4bar0281702'

I strongly dislike this kata and others like it. The hidden tests provide many more constraints than explained in the problem. Either provide the tests or explain in great detail what the constraints are.

The purpose of codewars is to learn. Because this problem seems easier at first, I tried to solve for the easiest and quickest solution only to find out that it's a little more complex than I thought. "Oh an error, there's a new constraint. Oh another error and it now seems I need to solve for something different than I originally thought." Rinse and repeat. I ended up spending so much time not learning because I'm trying to discern what the problem is asking.

Thumbs down for problems presented like this until they show the tests or provide a better description. I'm here to learn, not to play "try and guess what the problem is really asking."