Since the timeline of the game is meant to be quite a while you'll be going through quite a few agents even if they never get caught/killed.
So here's my thought process.
An agent has, lets say Skill 5 herbalism, knowing a skill and being able to teach the skill are two different things so some other stat will be required to be an effective teacher if you decide to retire them. I'm leaning towards a general "intelligence" stat.
Similarly, if you want them to write their skills down the agent needs to be literate so a writing skill will determine the quality of the book they make. My thinking is that they'd need half the writing skill relative to the skill in question to successfully write it down in a way your new agents can learn from.
When recruiting a new agent you can assign them to study, either under a mentor, or from a book. Mentorship would be better in terms of quality but not speed.
Getting an education in something is good and all but it isn't a replacement for hands-on experience, so if the agent had a level 10 swordsman mentor them they wouldn't step out of the class a level 10 themselves, instead they'd gain experience in that category faster. You could also only have them gain up to a certain level, have them do something useful with it and them send them back for more education once they reached the end of their experience boost.
This training process takes time, so when the new agent is "done" several in-game months have passed, if not years depending on how much you told them to study, and I'm sure the complexity of the subject matter will also be a factor.
So here's my thought process.
An agent has, lets say Skill 5 herbalism, knowing a skill and being able to teach the skill are two different things so some other stat will be required to be an effective teacher if you decide to retire them. I'm leaning towards a general "intelligence" stat.
Similarly, if you want them to write their skills down the agent needs to be literate so a writing skill will determine the quality of the book they make. My thinking is that they'd need half the writing skill relative to the skill in question to successfully write it down in a way your new agents can learn from.
When recruiting a new agent you can assign them to study, either under a mentor, or from a book. Mentorship would be better in terms of quality but not speed.
Getting an education in something is good and all but it isn't a replacement for hands-on experience, so if the agent had a level 10 swordsman mentor them they wouldn't step out of the class a level 10 themselves, instead they'd gain experience in that category faster. You could also only have them gain up to a certain level, have them do something useful with it and them send them back for more education once they reached the end of their experience boost.
This training process takes time, so when the new agent is "done" several in-game months have passed, if not years depending on how much you told them to study, and I'm sure the complexity of the subject matter will also be a factor.