As a jr or early mid level you can expect to have the majority of the details ironed out and nicely laid out for you to work on, but someone at some point had to actually figure it out and put it in the ticket. Whether that is you or someone else likely depends on your level, the stage of the company, etc.
edit: anyone who is downvoting this, please leave a comment with where you disagree. i'm unsure if i'm being received negatively on content or on tone
I would, but that's a detail that a senior dev like yourself should be able to figure out without people just providing it for you.
As for why the downvotes, hypothesis 1: People might misconstrue your position as "senior ICs are supposed to design the system entirely on their own". I understand you as "management provides the direction and some design constraints, seniors fill in the details, juniors just implement specifications from the seniors", which matches my experience.
Hypothesis 2: Maybe it's a culture thing? I'm guessing from your user name that you're from Europe, and I'm from Germany. Maybe the downvoters are literally coming from a different place? (Don't know how it would be different over there though.)