[tacostakohashi]

I think it all comes down to him testing his work, attention to detail, and taking responsibility for making it work, just like anyone else.

I don't really think "typo" is a useful word in this context. It's a sequence of characters that... _does not work_ and _was not tested_. The fact that it is close to a different sequence of characters that would work, or that a human could recognize it for that other sequence, isn't really relevant.

Some of the engineering approaches you mention can help, but at the end of the day he has to be responsible for verifying that things work. Tests, schemas, etc. can help, but you don't want to get into a game of "the test/linter/AI didn't catch this for me, therefore it is broken".

I've worked with plenty of people over the years with linguistic quirks, like spelling insisting on spelling "deliminator", or "pluggin", or whatever, but if the code works, it works.