Title: MessageBuilder::withFile
Published: May 20, 2026

---

# MessageBuilder::withFile( string|WordPressAiClientFilesDTOFile $file, string|null $mimeType = null ): self

## In this article

 * [Description](https://developer.wordpress.org/reference/classes/wordpress-aiclient-builders-messagebuilder/withfile/?output_format=md#description)
 * [Parameters](https://developer.wordpress.org/reference/classes/wordpress-aiclient-builders-messagebuilder/withfile/?output_format=md#parameters)
 * [Return](https://developer.wordpress.org/reference/classes/wordpress-aiclient-builders-messagebuilder/withfile/?output_format=md#return)
 * [Source](https://developer.wordpress.org/reference/classes/wordpress-aiclient-builders-messagebuilder/withfile/?output_format=md#source)
 * [Related](https://developer.wordpress.org/reference/classes/wordpress-aiclient-builders-messagebuilder/withfile/?output_format=md#related)
 * [Changelog](https://developer.wordpress.org/reference/classes/wordpress-aiclient-builders-messagebuilder/withfile/?output_format=md#changelog)

[ Back to top](https://developer.wordpress.org/reference/classes/wordpress-aiclient-builders-messagebuilder/withfile/?output_format=md#wp--skip-link--target)

Adds a file to the message.

## 󠀁[Description](https://developer.wordpress.org/reference/classes/wordpress-aiclient-builders-messagebuilder/withfile/?output_format=md#description)󠁿

Accepts:

 * File object
 * URL string (remote file)
 * Base64-encoded data string
 * Data URI string (data:mime/type;base64,data)
 * Local file path string

## 󠀁[Parameters](https://developer.wordpress.org/reference/classes/wordpress-aiclient-builders-messagebuilder/withfile/?output_format=md#parameters)󠁿

 `$file`string|WordPressAiClientFilesDTOFilerequired

The file to add.

`$mimeType`string|nulloptional

Optional MIME type (ignored if File object provided).

Default:`null`

## 󠀁[Return](https://developer.wordpress.org/reference/classes/wordpress-aiclient-builders-messagebuilder/withfile/?output_format=md#return)󠁿

 self

## 󠀁[Source](https://developer.wordpress.org/reference/classes/wordpress-aiclient-builders-messagebuilder/withfile/?output_format=md#source)󠁿

    ```php
    public function withFile($file, ?string $mimeType = null): self
    {
        $file = $file instanceof File ? $file : new File($file, $mimeType);
        $this->parts[] = new MessagePart($file);
        return $this;
    }
    ```

[View all references](https://developer.wordpress.org/reference/files/wp-includes/php-ai-client/src/builders/messagebuilder.php/)
[View on Trac](https://core.trac.wordpress.org/browser/tags/7.0/src/wp-includes/php-ai-client/src/Builders/MessageBuilder.php#L153)
[View on GitHub](https://github.com/WordPress/wordpress-develop/blob/7.0/src/wp-includes/php-ai-client/src/Builders/MessageBuilder.php#L153-L158)

## 󠀁[Related](https://developer.wordpress.org/reference/classes/wordpress-aiclient-builders-messagebuilder/withfile/?output_format=md#related)󠁿

| Uses | Description | 
| [MessagePart::__construct()](https://developer.wordpress.org/reference/classes/wordpress-aiclient-messages-dto-messagepart/__construct/)`wp-includes/php-ai-client/src/Messages/DTO/MessagePart.php` |

Constructor that accepts various content types and infers the message part type.

  | 
| [File::__construct()](https://developer.wordpress.org/reference/classes/wordpress-aiclient-files-dto-file/__construct/)`wp-includes/php-ai-client/src/Files/DTO/File.php` |

Constructor.

  |

| Used by | Description | 
| [MessageBuilder::__construct()](https://developer.wordpress.org/reference/classes/wordpress-aiclient-builders-messagebuilder/__construct/)`wp-includes/php-ai-client/src/Builders/MessageBuilder.php` |

Constructor.

  |

## 󠀁[Changelog](https://developer.wordpress.org/reference/classes/wordpress-aiclient-builders-messagebuilder/withfile/?output_format=md#changelog)󠁿

| Version | Description | 
| [0.2.0](https://developer.wordpress.org/reference/since/0.2.0/) | Introduced. |

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