Heat up the oil in a pan and add the garlic to toast for a few minutes being careful that it doesn't burn.
When the garlic starts releasing its scent, add the cherry tomatoes cut in half or in four parts if too big. Add a pinch of salt to the tomatoes so that they release their juice quicker. Cook for about ten minutes or until soft over medium heat stirring often to avoid it sticking. If you feel they are too dry, add a splash of water from time to time to keep it moist and creamy but not too much otherwise they will taste as if boiled. When they are soft, you can keep gently cooking on slow heat.
Meanwhile, put a pot full of water to boil and add a pinch of salt. When the water boils, put the agretti and cook for 4 to 5 minutes.
When the time is up, transfer the agretti to the skillet with the tomatoes using a tong and remove the garlic.
Add the spaghetti in the same pot and water where you cooked the agretti. Cook the pasta following the package instruction and try it before draining it.
When the pasta is cooked, drain it and transfer it to the skillet together with the tomatoes and the agretti. Stir for a few minutes so that all the flavors and ingredients and perfectly mixed and blending together.
Notes
Important tip: Before draining the spaghetti, remove a ladle or a cup of cooking water and set it aside. If the mix in the skillet becomes too dry, add the water to make it moist and rich.