[{_id:"Foo",flag1:true,flag2:true,flag3:false},{_id:"Bar",flag1:true,flag2:false,flag3:true}]

db.collection.aggregate([{$project:{status:{$function:{"body":"function (flagA, flagB, flagC) {if (flagA && flagB && !flagC) { return 'ok'} return 'broken'}","args":["$flag1","$flag2","$flag3"],"lang":"js"}}}}])