I would say both. For starters, tools/weapons allowed us to obtain fresh meat pretty much at will and fire later allowed us to cook it and make it much easier to metabolize. I would also say that we did not truly "discover" fire until we figured out how to start a fire using tools so we didn't have to wait for lighting to strike some tree and hope that we could keep the fire going until the next storm. Without fire, we would have no cooking, but without weapons, edged or otherwise, we would still be fragile creatures with big heads eating bugs, berries and maybe carrion and teetering on the brink of extinction if we had not already died out.. Some now theorize that having that abundance of easy to digest animal protein is one of major things that sped up the growth and increased complexity of our brain. Remember that while some humans had been eating wild cereals like barley for thousands of years, we didn't start actually farming it until 10-11,000 years ago in place like Turkey and that took a long time to spread to other parts.
Both have had a big part in other evolutionary changes that we don't even think about. Our teeth changed to reflect our more omnivorous eating habits, but the ALIGNMENT of our teeth also changed from meeting edge to edge to overlapping when we no longer really needed to use them as "tools." and probably reduced the size of our canines compared to other primates because we no longer needed them as "weapons" I have read articles that said that our evolution accelerated exponentially once we started and I read one today that says that continues to accelerate at an ever greater pace. Now that most people have unfettered access to nutritionally dense food in great quantities, we are getting bigger and I don't just mean fatter. Early modern humans were smaller and needed perhaps 1/3-1/2 as much food as Neanderthal to survive. Today, we are still pretty efficient, but the even greater intake of protein has caused even "historically short" people like the Japanese to get taller.