According to m0sa, the search parameter behavior is by design:

It's just named badly. Consider thinking about it as hasAnswerWithScoreGreatherThanZero.

Naming aside, I actually prefer the current behavior, because it gives me more flexibility in search. I can combine isanswered and hasaccepted parameters to get any combination of "answer with positive score" and "accepted answer" I want:

• answer with positive score: yes, no, doesn't matter
• accepted answer: yes, no, doesn't matter

If isanswered automatically included hasaccepted, the search possibilities would be fewer.

So I think it's the help center that should be fixed. Until recently, the parameter was not documented there at all. After my request The "isanswered" search parameter documentation is incorrect its description was added, but an incorrect one.

According to m0sa, the search parameter behavior is by design:

It's just named badly. Consider thinking about it as hasAnswerWithScoreGreatherThanZero.

Naming aside, I actually prefer the current behavior, because it gives me more flexibility in search. I can combine isanswered and hasaccepted parameters to get any combination of "answer with positive score" and "accepted answer" I want:

• answer with positive score: yes, no, doesn't matter
• accepted answer: yes, no, doesn't matter

If isanswered automatically included hasaccepted, the search possibilities would be fewer.

So I think it's the help center that should be fixed. Until recently, the parameter was not documented there at all. After my request The "isanswered" search parameter documentation is incorrect its description was added, but an incorrect one.