There’s nothing worse than having to execute someone else’s minute breakdown of work. People should be responsible for executing their own ideas. Then you get feedback on what was and wasn’t correct, and have only yourself to blame.
Having that ownership stimulates a much greater level of craftsmanship and skill growth. Documentation is great, but the idea that a spike author and implementor should be different people is awful.
If the person who does it just remembers it themselves and doesn’t do anything to help the other developers then they haven’t completed the spike.