Saute leek, celery, carrot, green pepper, and garlic in olive oil 7 minutes. Add tomatoes and cook until they release their juices. Add stock and bring to a boil; then reduce heat and simmer 10 minutes. Return to a boil; add green beans, yellow squash, and zucchini. Lower heat to a simmer; cook until beans and squash are just tender. Stir in fresh herbs; add salt and pepper.