Since 1.1.0 the skill bonuses are visible on agent's details, and a couple of them apply to too many areas.
Army recruitments cost reductions as written:
-5% Recruiter (upon successful action on own settlement)
-5% Accountant (upon successful action on own settlement)
-5% Instructor (in local province while standing idle)
They all apply both to the Own Settlement action and to Standing Passive for up to 30% reduction (I have tested it).
Similary Experienced Tactician should work only for embedded armies, but also works for Standing Passive.
The skills either don't work as intended or the descriptions are false.