The Surface Diagnostic Toolkit is recommended for vitually any hiccup or ailment a surface device might show.
But what does it it actually do?
So far, all I can see is, that it checks for open updates, downloads these if detected and reinstalls all MS Store Apps.
After a restart, it goes on with a series of tests, mostly concerned with power, the different positions of SB, the screen - including touch, the sound system and invisibly, some connectivity.
The results of the tests are shown, but I have never seen any repair activity reported. You are then invited to either contact Microsoft, rerun or quit.
The tool shows some oddities. For example, it will not replay the sound recording, but it will not tell me whether it considers the sound output out of order or whether it has not made a recording in the first first place. And all this when the sound system is completely in order and up and running.
It never ever passes the connected standby test, but this too is in perfect order.
It is recommended for camera issues, for usb issues, for keyboard and mouse issues - even for surface dock issues but it does not seem to do any testing here.
So what does it actually do? Is therr any documentation? A description of activities? Does anybody know more?