The Cincinnati chili dog is decided by the chili, and the chili is unlike any other chili in the country. A hot dog goes into a soft bun and over it goes Cincinnati chili: a thin, fine-ground, almost saucy meat preparation seasoned in the warm-spice direction rather than the chile-heat direction, with cinnamon and other sweet baking spices in the mix. It is the defining component and the thing that makes this a regional build rather than a generic chili dog. The sauce is finished with a tall haystack of finely shredded mild cheddar, a scatter of raw chopped onion, and a stripe of yellow mustard underneath.
The craft is in the order and the texture. The chili is built thin and smooth on purpose, closer to a gravy than a stew, so it coats the dog along its full length and soaks into the bun instead of falling out the ends in clumps. The frankfurter is the firm, salty spine the soft, wet load needs; the bun is kept soft so it yields against the chili rather than fighting it. The cheese is shredded fine and piled high so it half-melts against the hot sauce into a dense cap, which is the textural signature of the build and the reason the order is sometimes called a way: mustard and onion on the dog, chili over it, cheese over that, assembled fast at a counter and handed across before the bun gives out.
The variations follow the same Cincinnati grammar applied to the dog instead of spaghetti. The cheese Coney is the standard build above; ordered without the cheese it is a plain chili dog in the local style; the addition of beans or extra onion follows the same way-counting logic the chili parlors use over pasta. Beyond Cincinnati, the broader Coney family runs a beanless loose meat sauce without the sweet spicing, the same idea spoken in a different town's accent. Each of those is a codified build with its own rules, and each deserves its own article rather than being crowded in here.