Recall: "Come" "Here"
Much like your dog’s name, teach your pup that the sound of “come” means “holy cow, you sure want to be over here right now!”. Reinforce it often and early!
As always, concentrate first on building your pup’s desire to come and don’t name the behavior until you are very sure you are going to get it.
You can use your invitation to play voice, expectation of great things happening where you are, your energy, running away, the lure of a great game of tug, habit, environmental cues (say opening the car door if they like to go for a ride) etc. to trigger the desire to come - and then label it while it is happening.
Use hide and seek, or call dog to come see what you found in the environment (mole hill, stick, pinecone, toy...) or play dog recall with friends for treats (where your dog has to leave one person with treats in order to get treats from the person who says “Fido, come”.
A recall behavior is actually the sum of 4 behaviors = stop what you are doing + head turn + come to you + hand in collar
Include hand in collar so that dog likes to come very close in to you and doesn’t just do a fly by and bounce between you and the next thing of interest.
Coming in for a nose touch (repeated touches are also good) before sending them off again to explore is a good game.
Make sure that “come” doesn’t get associated with the end of something good - many quick “come” and release back to play is much better than one “come” to signal the end of puppy play, exercise, training, outdoor time, exploring etc....
Finally, for the purposes of agility specifically, it might be a good idea not to corrupt your emergency/real life/ let's not chase the deer shall we, "come" command. People often use :"come" on course meaning a whole variety of things: come toward me, look at me, go faster, and my favorite application - since you area already on the correct path, but I am nervous about this section of the course, I will call you off of it and create the problem I was nervous about.
Instead think about training a "here" command that means the same thing as "come" but could be used on course, reserving the "come" for the real deal.