And she sets about settling into Ponyville.
She learns her way around - here's where she can buy carrots and bunched dandelions and clover sprouts; here's where she can get a case for her crown and cases for everpony else's necklace so they don't have to wear them or leave them lying around loose; here's a shortcut between Guiding's house and the tower the twins live in together. This is when this little town wakes up in the morning and this is when everything closes at night. This is what her friends do all day: Cherry Cordial farms and looks after critters. Brightblaze tinkers with gadgets kind of singlemindedly (though she also flies). Silver Streak plays violin and and reads and wanders around looking at things. Guiding Star does fortune-telling for spare bits and belongs to a dance group and volunteers for anything going on in town that could use amateur decorating (Joy is often with her when she does this). Joy also wanders around being sociable and helpful and cooks, itinerantly, for anypony who'll spare him kitchen space.
And Clarity learns the organizational system of the library, with Blueberry's considerable help, and she studies and explores.
And when she's been in residence for just shy of a week, she gets a letter from the Princess, which contains six tickets to the Grand Galloping Gala. Aww, that's thoughtful. Clarity's never been before.
She goes out to see which of her friends she'll run into first if she takes a meandering path through town.
"How do you do it? This sounds awesome. Even if I don't get the aerial vantage point, I like knowing things."
She smiles slightly. "Well - it's really just looking at things," she says. "Seeing them properly. And then drawing conclusions from what I see. If somepony is fretting indecisively in their doorway and scanning the sky for clouds, and I see an umbrella behind them, it's likely that they are trying to decide whether or not they need it. If two ponies are approaching the same crossroads from different directions and neither is looking where they are going, I should land and warn one."
"Huh. I'm usually thinking about other things too much to figure them out like that - I'll be walking down the street trying to compose a report on friendship for Celestia, I should send the first one in soon, or I'm trying to learn my way around and can't interpret things like that at the same time. That's impressive multitasking."
"I have considerable practice," she says. "I'm curious about your report on friendship. What notes have you gathered so far?"
"Well, I'm hoping to stick to more or less one theme per letter, in case the rate of new observations drops off after a while and she expects the reports to keep up a the same frequency, but possible topics include the one I just mentioned - that is, how much time ponies should spend with their friends and how to ask about it - and something about what friends do together, and something about how talking about past history can make them feel closer, and something about presents in general like the tickets or how Cordy always winds up feeding me something, and I might have a couple other things written down but I don't have the right notebook with me."
"Cordy likes to distribute food," she says. "I have noticed that. She once told me that it's because it's a simple friendly gesture she happens to be well placed to make."
"You could do something similar with books, but I think fewer ponies enjoy those as much."
"But it's an idea, anyway, as I get more acquainted with the library stock I should consider issuing book recommendations."
"She's very helpful! Which is good, because being a librarian would really be a full time job for one pony, and I have other things to do, but with her helping I can pick up what's left in my spare time. If the mayor gets back to me and says I have a budget I'm going to pay her."
"She is very unusual, yes. I'm sometimes surprised that she does not yet have her cutie mark."
"At the same time as my sister. She was testing her first set of flight boots and accidentally created a sonic rainboom. I observed the direction and distance and immediately realized she must have done it, even though I hadn't known she was working on anything at the time."
"And a sonic rainboom is what scared Cordy's squirrels. Interesting coincidence, isn't it?"
"Rather. Maybe lots of ponies were sort of - prompted by it. It was sort of relevantly inspiring; I was trying to do the magical equivalent of brute forcing my final exam and then it sort of reminded me that magic can just interact physically with the world."
She smiles. "It's possible that it prompted a lot of ponies. But I think I'd want to know why, if that turned out to be true."
"Yeah, it's not a known feature of rainbooms, or if it is, it's not documented well enough for me to have found it when I looked them up after the event."