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

---

# MessageBuilder::__construct( WordPressAiClientBuildersInput $input = null, WordPressAiClientMessagesEnumsMessageRoleEnum|null $role = null )

## In this article

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

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

Constructor.

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

 `$input`WordPressAiClientBuildersInputoptional

Optional initial content.

Default:`null`

`$role`WordPressAiClientMessagesEnumsMessageRoleEnum|nulloptional

Optional role.

Default:`null`

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

    ```php
    public function __construct($input = null, ?MessageRoleEnum $role = null)
    {
        $this->role = $role;
        if ($input === null) {
            return;
        }
        // Handle different input types
        if ($input instanceof MessagePart) {
            $this->parts[] = $input;
        } elseif (is_string($input)) {
            $this->withText($input);
        } elseif ($input instanceof File) {
            $this->withFile($input);
        } elseif ($input instanceof FunctionCall) {
            $this->withFunctionCall($input);
        } elseif ($input instanceof FunctionResponse) {
            $this->withFunctionResponse($input);
        } elseif (is_array($input) && MessagePart::isArrayShape($input)) {
            $this->parts[] = MessagePart::fromArray($input);
        } else {
            throw new InvalidArgumentException('Input must be a string, MessagePart, MessagePartArrayShape, File, FunctionCall, or FunctionResponse.');
        }
    }
    ```

[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#L43)
[View on GitHub](https://github.com/WordPress/wordpress-develop/blob/7.0/src/wp-includes/php-ai-client/src/Builders/MessageBuilder.php#L43-L65)

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

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

{@inheritDoc}

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

Adds text content to the message.

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

Adds a file to the message.

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

Adds a function call to the message.

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

Adds a function response to the message.

  |

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

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

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