Series: Finishing School #1
This was a kind of cute young-adult steampunk story about a tomboy in possibly Victorian times (there's talk of a telegraph device and gas lighting) who gets packed off to finishing school to try to polish off her rougher edges. As it turns out, however, the finishing school in question is only teaching the finer aspects of moving about in society in order to create expert intelligence agents, which is much more to Sophronia's liking. She can get behind fashion choices when they're used for camouflage, basically.
So the concept is kind of cute and silly but also somewhat entertaining. Sophronia reminds me a little of Flavia de Luce although she's a bit older. I think I'll see if my library has the next one in the series.