How do you tell in real time whether news is actually tradeable or already priced in?

I keep getting this wrong and i don't think i have a rule, just a gut feel that's been expensive.

the pattern is always the same. headline drops, price is already 4% into the move by the time i've read it, and i can't tell if that's the whole reaction or the first leg. sometimes i chase and it's the top. sometimes i sit it out and it runs for two more days. after the fact everyone explains why it was obvious.

what i've noticed but can't turn into a rule. regulatory stuff seems to move things for days, exchange or hack news is violent and over in hours. and anything that was already rumored barely moves at all when it's confirmed, which makes me think the thing i should be reading is not the news but how much of it was already leaked.

so for people who actually trade around news, do you have something concrete you check, or is it discretionary. is it volume behavior in the first minutes, whether the move holds a level, funding, something else entirely. and do you separate news that changes the actual thesis from news that just moves price for a day, because i treat those the same and i suspect that's the mistake