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[@salesforce/b2c-tooling-sdk](../../modules.md) / [clients](../index.md) / runWithMrtReadOnlyListener

# Function: runWithMrtReadOnlyListener()

> **runWithMrtReadOnlyListener**\<`T`\>(`listener`, `fn`): `T`

Defined in: [packages/b2c-tooling-sdk/src/clients/mrt.ts:147](https://github.com/SalesforceCommerceCloud/b2c-developer-tooling/blob/1dedfc1ffefa01c3d5bff62c8f7e7e682a1a91cd/packages/b2c-tooling-sdk/src/clients/mrt.ts#L147)

Run `fn` with a `listener` for reads served in read-only mode. The middleware
reads it from request-scoped context, so operations never thread it through —
consumers (e.g. the CLI) set it once per unit of work.

## Type Parameters

### T

`T`

## Parameters

### listener

[`MrtReadOnlyListener`](../type-aliases/MrtReadOnlyListener.md)

### fn

() => `T`

## Returns

`T`