Is tomato foliage edible?

Tomato leaves are edible, both the articles agree on that. The Modern Farmer article says you'd have to eat pounds and pounds of them before you'd get appreciable amounts of toxins to make you ill, and even then it's more of an upset stomach issue. Some people might react more to Tomatine, which is the mild toxin in the leaves, and is also in green tomatoes. People eat fried green tomatoes enough without getting sick.

For me the cooking issue is flavor, the leaves are pretty pungent and I haven't seen a recipe that uses them without burying them in the middle of a host of other ingredients. They're too strongly flavored to be a salad leaf, and they generally need to be cooked as they're tough.

The flavor thing can work out, you can put a couple of tomato leaves in a tomato sauce to boost flavor in the last few minutes of cooking, then pick them out. They can also be put into a pesto, adding a strong tomato flavor.

The message is you can eat them as long as it's not very large amounts, which you'd probably not want to do anyway because they're so strong.

EDIT: if you grow tomatoes you'll have tomato leaves for weeks, not one single harvest. Once the plants mature and you start to get tomatoes you'll typically prune many of the leaves off to concentrate the plant's energy on ripening the tomatoes, that's actually when you get most of the edible leaves off the plant, a good time to make a pesto if you want to try it. You don't want to harvest many leaves when the tomatoes start ripening as the plant needs what's left for photosynthesis, but you could prune one or two to put into a sauce. As the last tomatoes ripen the plants start to die back and you probably wouldn't want to eat them then.