What does "What are you up to?" mean? [closed]

I overheard my manager asking "What are you up to?"

What does that idiom mean? Is it an informal/negative way of asking??

"What are you up to?" means

"What have you been doing lately?".

If you add an adverb to the end of the phrase, for instance,

"What are you up to tonight?" or "What are you up to this summer?"

it can be interpreted as

"What are you planning to do tonight?" or "What are you planning to do this summer?".

Can I also add that the intention should be determined by the tone the person uses when asking. If they are asking it in a light hearted open way, they genuinely want to know what you are doing (at the moment or a later point in time).

If there appears to be suspicion in their tone, they may be implying that you are "up to" something you shouldn't be and should stop.

A common phrase is "are you up to mischief?” which means "are doing something naughty, you shouldn't be"?