Generally as a senior dev part of your job description is to figure the details out. Not have them provided for you.

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