I like the idea. Just tried it on a few files on my project, so here is some feedback:
1. I think the 88 character limit is way to low. Personally my requirement for the character limit is that I can view two files next to each other (mainly for diffing), and I can easily fit up to 140 characters on there. Obviously that depends on screen resolution and font size, but I think a limit of 100 - 120 would make more sense with bigger monitors becoming more widespread 2. I think it should preserve new lines on the top level, I often use them for organization 3. Being able to turn the formatter off for sections of code (like // clang-format off) would be great