I could be there, yet I'll stay hidden.
History records many event, but some remain hidden
Hidden I'll stay, but you'll need me.
While not all are recorded, a story of the past is still needed.
Need me you will, so I may appear.
History exists because you 'will' (in future) need it
Appear I may, I don't decide.
It's not the one who wrote history decides its content,
Decide I don't, my master does.
But the people / things in the past.
I'm a word, I tell you words.
History is a word, and it tells you 'his-story' in words
I've a task, you know my task.
A task to record the past
I'm short, I shorten your path.
Human history is short, yet contains valuable information to shorten your path (to success, for the opportunist friend)
I've the answer, now tell me it!