I'm trying to figure out the name of a sci-fi short story I read a while back. Hours of Googling were no help. Can anyone figure this out?
The punchline of the story is that all of humanity was created for the purpose of providing a missing tool which is required to fix a broken alien spaceship was stranded somewhere in the solar system (Jupiter?). In the end, a child with a toy, which turns out to be the requisite tool, stumbles into a spaceship launched to that planet, and it all turns out to have been designed by the aliens to get them their missing tool, so that they can fly back home.