Do you mean, for instance, a nameless SW crewman who has no lines and might not even be seen on screen, or one that technically has a role but is so minor that they won't, as people have said below, be missed? If the first, is there any reason you can't just say that the agent was a bit extra in a bad fanfic rather than canon? Not that you need to, by any means, but it would neatly avoid the issue entirely. Just curious.

This is why the PPC often recruits extras that are doomed to die-- they will NEVER show up again in their source material. If there is even the slightest chance of that character showing up again and playing even a small part in a canon work, I'd avoid it. We'd hate to cause a multidimensional paradox with somebody being in the PPC when they should have been in their canonical material.

If that's not the case? If the character is so totally minor and definately will not be mentioned every again Go for it.

KG's statement of 'extras' in the sense that he's thinking of I don't think is precisely right, as we've had actual canons recruited to the PPC who were major characters in their canon, the argument being that recruiting them at the point after their role in canon ends or just right when they are supposed to die makes them eligible since they are not going to contribute to the plot any further on a personal level.

What you're suggesting however, I take it you mean small minor characters from the canon and not a fic? I'd like to argue that this sort of thing can be tricky to explain away, since Star Wars has a universe with multiple levels of canon where even the most unexpected and most initially considered minor characters end up having their own personal and important contribution to make to the history of the canon and become main or secondary characters in their own right.

There's lots of agents like that, sort of "extras" for lack of a better term. My interpretation's been that canons are more the major characters in a given work, while actual natives are technically part of the canon but not actual canon characters, if that made sense? With the "canon" characters being more strongly tied to the 'verse than the extras who nevertheless would canonically exist.