The first thing that jumps out at me is the issue of scale- an Agent small enough to ride on someone else's shoulder would actually be something I'd like to see happen. It would, however, make actually affecting his environment very difficult, so he'd end up being either completely dependent on his partner or possessed of, I dunno, telekinetics or something. Disguises would help with this, but to do so they'd also have to eliminate the main trait that sets him apart from the other Agents.

If we're not leaving him a rat, I do have to question what would happen to the personality of the "host" the chip gets implanted into. There's some MAJOR ethical concerns to that, even if the host body is not sentient.

You have some detail going on here with what your agents are, but there's not very much of what they're like.

I'm not saying this is a necessarily a bad thing- certainly, having a species and some kind of background attached to them is a good thing- it's very useful to know when a character is human or not human, as the case may be!- but it doesn't give them anything to make them stand out as interesting characters, rather than things.

Yes, a character can be more memorable when these things add to them on top of them being memorable via being interesting characters due to their actions and personality, but it doesn't help them stand out.

Lemme try to explain this in different terms.

Let's think of characters in terms of food.

Your average poorly written character is junk food of various levels of quality. When you add things on top of that- loads of powers, extra special things, super unique things that don't really do anything but be there for the sake of being there- it's added junk. Sugar, sugar substitute, those dyes that make food all those great colors only found naturally in poisonous or venomous animals or plantlife- all that. It's fluff and adds no nutritional content.

When a character is written in a way that doesn't rely on those sort of things, it adds nutritional value. For example, let's take one of my favorite characters: Sam Vimes from Discworld.

Vimes starts off as a very sorry sad sack of alcoholism and profound cynicism. There is nothing about him that makes him apparently special in the grand scheme of things.

What makes him an interesting character is what he's like and how he reacts to everything. That's where the meat and potatoes is. Vimes doesn't become more interesting by being forcibly further and further up in terms of importance through the progression of what's going on in the Disc- it's his reactions and how they build on top of each other to give us a very vivid image of this man and what he's like. His reaction to things.

All you've given here is the uplifted character is lewd and has knowledge of Shakespeare and is fine with presumably gross things, which tells us very little in the grand scheme of things. As a character point, it's not all that compelling.

A few years back when I was first getting into the PPC, I read every single spin off, mission, side story and otherwise available PPC thing available online at the time. Kept up with loads of spin-offs since then and plenty of agent ideas.

I could not to save my life tell you how many of the ones that I found dead boring were the ones with all the junk food details added on because I don't remember them. There are a few that were memorable, but not as characters with compelling personalities or arcs. Instead, it was for the sheer amount of fluff that had been added on that resulted in something that was completely ridiculous and out of place.

I'm not saying that the uplift is a bad idea, but I do think you should consider more than just the what of the character; think about how they act, react, their personality, how they are.

When it comes to characters and writing, it should come down to qualities, not quantities.