Looking through the Core Rulebook and the forums it seems clear that character Attributes are static. The Year Zero Engine does have rules for improving attributes. I am wondering if the design decision for this has been explained somewhere.
Some background: A player wanted to create a scrawny, malnourished streetwise Scoundrel who would start with STR 2 and then (cue Coriolis gym montage) use their Explorer income and resources to put on some healthier muscle / brawn. Which made me speculate on dodgy Black Toad steroid-like drugs and what high-protein food stuffs the Gardeners Guild might produce. All with a good dose of plot hooks, building favours owed, etc. In effect, using what the player would like or wants to drive story events and make things more interesting than “after eight weeks of training and supplements your STR in now 3.”
Only it seems that Attributes are a one and done static choice made at character creation (in Coriolis TGD and other Free League games). I can see the problems of players ramping every attribute up if that is an option. (There is always the "choices have consequences" approach to this and the well-worn “so much power they choke on it” result.)
So what can the GM do if a player wants to increase an Attribute?