> ## Documentation Index
> Fetch the complete documentation index at: https://api-docs.hrizn.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Vehicle YMMT cascade

> Parent-required year → make → model → trim labels for content create (no JATO / MSRP)

Labels-only vehicle identity cascade used before `POST /model-landing-pages` or `POST /comparisons` with `source=catalog`.

**Scope required:** `content:write` (read-only keys cannot scrape the catalog).

**Hard rules:**

* One level per request (never dump the full national catalog).
* Responses are display labels only — no MSRP, body/drive, JATO ids, provider refs, or images.
* Create endpoints re-validate labels server-side; inventing free-text YMMT returns `400`.

## Endpoints

| Method         | Path                   | Body                    | Returns                                    |
| -------------- | ---------------------- | ----------------------- | ------------------------------------------ |
| `GET` / `POST` | `/vehicle-ymmt/years`  | `{}` (optional)         | `{ years: number[] }`                      |
| `POST`         | `/vehicle-ymmt/makes`  | `{ year }`              | `{ year, makes: [{ make }] }`              |
| `POST`         | `/vehicle-ymmt/models` | `{ year, make }`        | `{ year, make, models: [{ model }] }`      |
| `POST`         | `/vehicle-ymmt/trims`  | `{ year, make, model }` | `{ year, make, model, trims: [{ trim }] }` |

Subject to the same API key rate limits as other Public API routes.