This sounds like a nice change. We have something similar at work, but where the build will fail if it doesn’t adhere to the clang-format style we use. Having a reformatter bot would be even nicer, though we’ve still saved a lot of time during reviews.
The only thing I can recommend is picking the very latest clang-format version you can get your hands on for the bot. That way its longevity in terms of staying packaged in distros, being supported upstream etc will be maximized.
We are in the situation now that we set up our CI format check back when clang-format-4.0 was recent, and have recommended our devs to auto-format on save using that version, to avoid a yelling CI bot, but now clang-format-4.0 is ancient and we’re considering bumping the version on our CI, which will bring with it some behavioral changes (even given the same config).
So just a recommendation to go with the latest, to postpone that day for you as much as possible. Our situation is a little different of course, and you guys may be able to run the same version on the bot for eternity.