how come voldemort let snape do anything other than kill harry or hold him there until voldemort could come kill harry himself once he successfully kidnapped him

then voldemort wouldn't need a spy anymore because harry potter would be dead

how is snape going to explain to voldemort how harry managed to survive a potion that was supposed to kill him

why was voldemort cool with snape killing harry didn't he want to do it himself

why couldn't snape come up with something to explain an inability to kidnap harry while harry was with the dursley's

why didn't voldemort ask snape to kidnap harry before

why didn't voldemort ask snape to just murder harry where he was and split