---
url: >-
  https://adk.nht.io/api/@nhtio/adk/batteries/media/functions/unsupportedForMutationReason.md
---

# Function: unsupportedForMutationReason()

```ts
function unsupportedForMutationReason(mimeType: string): string | undefined;
```

Defined in: [src/batteries/media/formats.ts:119](https://github.com/NHTIO/ADK/blob/v1.20260713.1/src/src/batteries/media/formats.ts#L119)

Reason a mutation verb cannot run against this MIME type, or `undefined` when mutation is
allowed. Returns a reason string (not a throw) so callers compose model-actionable failures.

## Parameters

| Parameter  | Type     | Description          |
| ---------- | -------- | -------------------- |
| `mimeType` | `string` | The media MIME type. |

## Returns

`string` | `undefined`

A human-readable reason, or `undefined` when mutation is supported.