Preheat oven to 450 degrees F.

Lightly brush a baking sheet with olive oil and arrange the tomato slices and 3 garlic cloves in one layer. Brush tomatoes and garlic with olive oil and season with salt and pepper. Roast until the tomatoes are lightly browned and the garlic is tender, about 20 minutes. Transfer tomatoes and garlic to a blender. Add balsamic vinegar and 1 tablespoon water and puree until smooth. Add more water if necessary. Taste and adjust seasoning with salt and pepper. Reserve sauce and keep warm.

In a food processor or blender coarsely chop the remaining garlic clove. Add the cilantro, chives, and parsley and process until finely chopped, scraping down the sides with a rubber spatula if necessary. Transfer the herb mixture to a shallow dish. Add the bread crumbs, stirring thoroughly to combine, and season with salt and pepper.

Brush the cod fillets with olive oil and then dredge in the herb and bread crumb mixture, making sure the fish is well coated on all sides. Arrange the coated fillets on a lightly oiled baking pan. Roast the fillets in the middle of the oven until just cooked through, 7 to 10 minutes. Serve the roasted cod on the sauce.