[greenail]

If you don't have a relationship with the executive you should ask for an agenda and clarity on the goal of the meeting. You should say "you need the context so that you can prepare and ensure a productive meeting". Even if there is a one or two sentence description you should ask for more info. This does two things, first it helps you prepare and 2nd if they don't provide an agenda you get some forewarning that something is going on. Worse case they say no, best case they see you habitually doing good prep work.

[endtime]

I disagree with this advice. At least in the US, I think it could easily be interpreted as anxious or rigid. Or even just make you seem too junior. Leaders need to be able to handle ambiguous meetings.

[greenail]

if you flip the script you'd never ask an exec you don't know for a meeting without giving context. This is common courtesy if you do it without seeming demanding.

"Looking forward to our discussion. Can you give me a bit more context for the meeting and an agenda? This way I can be sure to have enough time to properly prepare. Thanks..."

would you say no to that?