> ## Documentation Index
> Fetch the complete documentation index at: https://wiz-myvocal.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Edit the arrangement

> Edit an arrangement by merging the editable fields into the current immutable arrangement.

The body is an **edit request**, not a whole arrangement. The service merges your edit into the current immutable arrangement and re-validates the result.

### Header

<ParamField header="accessKey" type="string" required>
  API key for authentication.
</ParamField>

### Path

<ParamField path="projectId" type="string" required>
  The project identifier.
</ParamField>

### Body

<ParamField body="expectedVersion" type="number" required>
  The `arrangementVersion` you based this edit on. A mismatch is rejected with `47016`.
</ParamField>

<ParamField body="title" type="string">
  Song title, 1–120 code points.
</ParamField>

<ParamField body="styleSummary" type="string">
  Summary of the musical style, 1–500 code points.
</ParamField>

<ParamField body="tempoBpm" type="number">
  `null`, or between `40` and `220`.
</ParamField>

<ParamField body="sections" type="array" required>
  Sections to merge, addressed by `sectionId`: `{ sectionId, lyrics, styleNotes }`, in section order.
</ParamField>

### Validation rules

The merged arrangement must satisfy:

* 4–12 sections; every section `position` must equal its 1-based index.
* Section types: `INTRO`, `VERSE`, `PRE_CHORUS`, `CHORUS`, `BRIDGE`, `OUTRO`, `OTHER`.
* Each section `durationSec` is 5–60, and the durations must sum to the arrangement duration.
* At least one `VERSE` and one `CHORUS` must be present.
* Concatenated `lyrics`, trimmed, must be 20–2800 code points.

### Response

<ResponseField name="projectId" type="string">
  Project identifier.
</ResponseField>

<ResponseField name="version" type="number">
  The new arrangement version.
</ResponseField>

<ResponseField name="arrangement" type="object">
  The merged, validated arrangement.
</ResponseField>

<RequestExample>
  ```bash theme={null}
  curl --location --request PUT 'https://api.myvocal.ai/sound_clone/api/v1/music/projects/mup_.../arrangement' \
  --header 'accessKey: <your_api_key>' \
  --header 'Content-Type: application/json' \
  --data '{
    "expectedVersion": 1,
    "title": "Coast Road",
    "styleSummary": "Bright summer pop with driving drums.",
    "tempoBpm": 118,
    "sections": [
      { "sectionId": "<section_id>", "lyrics": "Where the highway meets the sea...", "styleNotes": "Warm pads" }
    ]
  }'
  ```
</RequestExample>

<ResponseExample>
  ```json 200 Success theme={null}
  {
    "code": 1,
    "message": "success",
    "data": {
      "projectId": "mup_...",
      "version": 2,
      "arrangement": { "durationSec": 90, "sections": [ "..." ], "requestId": "..." }
    }
  }
  ```
</ResponseExample>

<Warning>
  Editing the arrangement makes the current quote stale. Request a new quote before generating.
</Warning>

### Common errors

* `code = 47016`: `expectedVersion` does not match the current arrangement version. Re-read the project and retry.
* `code = 47001`: the merge produced an arrangement that violates a validation rule.
* `code = 47009`: the project does not exist **or** is not owned by your account.