---
title: "Score one beat's music bed."
method: POST
path: "/trailers/{jobId}/storyboard/music"
tags: ["Trailer"]
---

# Score one beat's music bed.

`POST /trailers/{jobId}/storyboard/music`

## Request

- Base URL: `https://docs.sleeperhit.studio/api/v1`
- URL: `https://docs.sleeperhit.studio/api/v1/trailers/{jobId}/storyboard/music`
- Auth: HTTP bearer

One endpoint, selected by `action`: `score` generates a new bed from a prompt, `apply-library` reuses a track already in My Library (no generation, and the way several beats come to share a tempo and key), `update` relevels or retimes the bed, `remove` clears it. Beds render with the Lyria engine, so they are never blocked by the fal balance; describe the SOUND rather than naming a real artist. Generating — `score`, or an `update` that changes the prompt or vocals — waits for the project's gate: while it is closed the call is refused with 409 `project_precondition_failed` and no bed is written or queued; `apply-library`, a level or timing `update` and `remove` stay open. Requires `Idempotency-Key`. Scope: `story:write`.

## Headers

- `Idempotency-Key` string, required

## Request body

- object
  - `action` 'score' | 'update' | 'remove' | 'apply-library', required
  - `sceneIndex` integer, required: Zero-based index of the beat.

## Response `200`

The updated music bed, plus a shareable per-beat preview link.

- object

## Other responses

- `400`: Request payload failed validation. The error message names the offending field.
- `401`: Missing, malformed, revoked, or expired API key.
- `403`: API key is valid but lacks the scope, is blocked by IP allowlist, or the account is disabled.
- `404`: The named project or source does not exist or is owned by another account.
- `429`: Rate limit for this API key + IP + route family was exceeded.
- `500`: The API failed unexpectedly. Safe to retry with the same Idempotency-Key.

---

[API](https://skmtc.dev/sleeperhit/apis/sleeper-hit-studio-story-api.md) · [All operations](https://skmtc.dev/sleeperhit/apis/sleeper-hit-studio-story-api/llms.txt) · [OpenAPI document](https://skmtc.dev/sleeperhit/apis/sleeper-hit-studio-story-api/revisions/4534f5d25540?raw)