"Huh. Uh, I will do my best to keep your secret assuming it's not blatantly horrible or something."

'Assuming it's not blatantly horrible' is not, actually, sufficient, but the gestalt confidence level for secrecy reported by the affixation monitor is sufficient.

Unique Classes can be considered extreme outliers. The property of Avowed which allows affixation of powers is not a simple number, and sometimes it can be, for lack of a better word, biased and unstable. In some cases instability can result in the painful death of the Avowed in question, as well as uncontrolled manifestation of powers, among other negative outcomes.

Unique Classes are designed to work with the bias and create stability, while also creating a set of powers that are at least marginally useful to the bearer, and secondarily, to Earth and to the Triplanets.

In your case, your stability is high, but your bias is very strong. It makes you unsuitable for most Classes. I decided not to deny you the opportunity other potential Avowed receive and arranged for the design of a Unique Class for you to affix if you accepted the Contract.

"Why didn't the instability thing ever happen before the Artonans found Earth, then?"

I'm sorry, but I will not answer that question.

"Gosh. Okay. Well, I do like my Skill, and am glad I'm not exploding or anything, and I guess I will go along with your model of the PR consequences. Anything else I should know about my class besides that it's working with some kind of magical bias I have?"

You may request features of future skills offered for affixation. However, there is no guarantee they will actually be offered.

"Well, I'd like some kind of warning when I'm going to need my Fortress skill operative, for one."

Request noted.

Affixation 2/3 complete.

"What are my level-ups going to be like in general? Will I get more spells, for instance?"

Do you want more spells?

You are likely to receive mostly Foundation points, skills, and skill upgrades. Spell impressions are moderately incompatible with your bias.

"Huh. I mean, most spells at the rank I was offered aren't great, I guess. Why are they incompatible?"

I don't think I can answer in a way you understand that would not be a lie or breach secrets. Spell impressions are very different from Skills 'under the hood'.

"What about wordchains? I know I'm not a Chainer but like if I just learn them extracurricularly are they in conflict."

Wordchains are just as different from spells as skills are. You may use them without worry.

"Okay... is it a coincidence that I do really like my primary skill or is that related to how I'm biased?"

That is unknown and debated even to those wizards who study such things.

"Are they gonna wanna study me, will I get research-subject summonses?"

Unlikely. The ethical constraints built into the Contract to prevent abuse forbid invasive study. They will have to convince you to volunteer or content themselves with passive data from skill use.

Affixation is almost complete.

"I wasn't imagining invasive research! - who's getting passive data about my skill use, what do they get about it."

The System throws up a section of the full text of the Interdimensional Warriors Contract.

TL;DR: The System monitors the strength and growth of skills and other magical features of Avowed and records data about their effects on the world, in order to better match summoners to summonees, prioritize emergency responses, and know when and how to affix new features. Only "Knights", "Honored" wizards of high rank, or "Arbitrators", have any ability to look at the raw data of exact times and circumstances powers were used, rather than the summarized profile that merely describes capabilities, and only if they have a reason, and the reason is recorded.

"Can I access those records?"

Yes.

Affixation is now complete. You will lose awareness of this scene momentarily. 

Thank you for your future service.

And she is in the taxi again. They appear to be on an enormous bridge. The Contract section is still up, and she has a new interface button - Activity Records

"Whoo! How long was I out?"

"About five minutes! Feeling alright? Please don't do whatever you do in here if it's flashy."

"I feel fine, and it's not at all, I'm very defense-oriented plus I can moon walk which I can't try very well with a seatbelt on."