Title: WP_Ability::validate_output
Published: February 24, 2026

---

# WP_Ability::validate_output( mixed $output ): true|󠀁[WP_Error](https://developer.wordpress.org/reference/classes/wp_error/)󠁿

## In this article

 * [Parameters](https://developer.wordpress.org/reference/classes/wp_ability/validate_output/?output_format=md#parameters)
 * [Return](https://developer.wordpress.org/reference/classes/wp_ability/validate_output/?output_format=md#return)
 * [Source](https://developer.wordpress.org/reference/classes/wp_ability/validate_output/?output_format=md#source)
 * [Related](https://developer.wordpress.org/reference/classes/wp_ability/validate_output/?output_format=md#related)
 * [Changelog](https://developer.wordpress.org/reference/classes/wp_ability/validate_output/?output_format=md#changelog)

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

Validates output data against the output schema.

## 󠀁[Parameters](https://developer.wordpress.org/reference/classes/wp_ability/validate_output/?output_format=md#parameters)󠁿

 `$output`mixedrequired

The output data to validate.

## 󠀁[Return](https://developer.wordpress.org/reference/classes/wp_ability/validate_output/?output_format=md#return)󠁿

 true|[WP_Error](https://developer.wordpress.org/reference/classes/wp_error/) Returns
true if valid, or a [WP_Error](https://developer.wordpress.org/reference/classes/wp_error/)
object if validation fails.

## 󠀁[Source](https://developer.wordpress.org/reference/classes/wp_ability/validate_output/?output_format=md#source)󠁿

    ```php
    protected function validate_output( $output ) {
    	$output_schema = $this->get_output_schema();
    	if ( empty( $output_schema ) ) {
    		return true;
    	}

    	$valid_output = rest_validate_value_from_schema( $output, $output_schema, 'output' );
    	if ( is_wp_error( $valid_output ) ) {
    		return new WP_Error(
    			'ability_invalid_output',
    			sprintf(
    				/* translators: %1$s ability name, %2$s error message. */
    				__( 'Ability "%1$s" has invalid output. Reason: %2$s' ),
    				esc_html( $this->name ),
    				$valid_output->get_error_message()
    			)
    		);
    	}

    	return true;
    }
    ```

[View all references](https://developer.wordpress.org/reference/files/wp-includes/abilities-api/class-wp-ability.php/)
[View on Trac](https://core.trac.wordpress.org/browser/tags/6.9.4/src/wp-includes/abilities-api/class-wp-ability.php#L567)
[View on GitHub](https://github.com/WordPress/wordpress-develop/blob/6.9.4/src/wp-includes/abilities-api/class-wp-ability.php#L567-L587)

## 󠀁[Related](https://developer.wordpress.org/reference/classes/wp_ability/validate_output/?output_format=md#related)󠁿

| Uses | Description | 
| [WP_Ability::get_output_schema()](https://developer.wordpress.org/reference/classes/wp_ability/get_output_schema/)`wp-includes/abilities-api/class-wp-ability.php` |

Retrieves the output schema for the ability.

  | 
| [rest_validate_value_from_schema()](https://developer.wordpress.org/reference/functions/rest_validate_value_from_schema/)`wp-includes/rest-api.php` |

Validate a value based on a schema.

  | 
| [__()](https://developer.wordpress.org/reference/functions/__/)`wp-includes/l10n.php` |

Retrieves the translation of $text.

  | 
| [esc_html()](https://developer.wordpress.org/reference/functions/esc_html/)`wp-includes/formatting.php` |

Escaping for HTML blocks.

  | 
| [is_wp_error()](https://developer.wordpress.org/reference/functions/is_wp_error/)`wp-includes/load.php` |

Checks whether the given variable is a WordPress Error.

  | 
| [WP_Error::__construct()](https://developer.wordpress.org/reference/classes/wp_error/__construct/)`wp-includes/class-wp-error.php` |

Initializes the error.

  |

[Show 4 more](https://developer.wordpress.org/reference/classes/wp_ability/validate_output/?output_format=md#)
[Show less](https://developer.wordpress.org/reference/classes/wp_ability/validate_output/?output_format=md#)

| Used by | Description | 
| [WP_Ability::execute()](https://developer.wordpress.org/reference/classes/wp_ability/execute/)`wp-includes/abilities-api/class-wp-ability.php` |

Executes the ability after input validation and running a permission check.

  |

## 󠀁[Changelog](https://developer.wordpress.org/reference/classes/wp_ability/validate_output/?output_format=md#changelog)󠁿

| Version | Description | 
| [6.9.0](https://developer.wordpress.org/reference/since/6.9.0/) | Introduced. |

## User Contributed Notes

You must [log in](https://login.wordpress.org/?redirect_to=https%3A%2F%2Fdeveloper.wordpress.org%2Freference%2Fclasses%2Fwp_ability%2Fvalidate_output%2F)
before being able to contribute a note or feedback.