---
url: 'https://adk.nht.io/api/@nhtio/adk/types/type-aliases/MediaBytesStoreFn.md'
description: >-
  Persists tool-generated media bytes into consumer storage and returns a {@link
  @nhtio/adk!MediaReader}. A byte-persistence conduit, not a mutation — returns
  a value and touches no turn state.
---

# Type Alias: MediaBytesStoreFn

```ts
type MediaBytesStoreFn = (
  ctx: TurnContext,
  id: string,
  bytes: ConduitBytes,
) => MediaReader | Promise<MediaReader>;
```

Defined in: [lib/contracts/turn\_runner\_context.ts:223](https://github.com/NHTIO/ADK/blob/v1.20260605.0/src/lib/contracts/turn_runner_context.ts#L223)

Persists tool-generated media bytes into consumer storage and returns a [@nhtio/adk!MediaReader](../../common/interfaces/MediaReader.md).
A byte-persistence conduit, not a mutation — returns a value and touches no turn state.

## Parameters

| Parameter | Type                                          |
| --------- | --------------------------------------------- |
| `ctx`     | [`TurnContext`](../interfaces/TurnContext.md) |
| `id`      | `string`                                      |
| `bytes`   | [`ConduitBytes`](ConduitBytes.md)             |

## Returns

| [`MediaReader`](../../common/interfaces/MediaReader.md)
| `Promise`<[`MediaReader`](../../common/interfaces/MediaReader.md)>