Title: WP_Ability Published: February 24, 2026 --- # class WP_Ability {} ## In this article * [Description](https://developer.wordpress.org/reference/classes/wp_ability/?output_format=md#description) - [See also](https://developer.wordpress.org/reference/classes/wp_ability/?output_format=md#see-also) * [Methods](https://developer.wordpress.org/reference/classes/wp_ability/?output_format=md#methods) * [Source](https://developer.wordpress.org/reference/classes/wp_ability/?output_format=md#source) * [Changelog](https://developer.wordpress.org/reference/classes/wp_ability/?output_format=md#changelog) [ Back to top](https://developer.wordpress.org/reference/classes/wp_ability/?output_format=md#wp--skip-link--target) Encapsulates the properties and methods related to a specific ability in the registry. ## 󠀁[Description](https://developer.wordpress.org/reference/classes/wp_ability/?output_format=md#description)󠁿 ### 󠀁[See also](https://developer.wordpress.org/reference/classes/wp_ability/?output_format=md#see-also)󠁿 * [WP_Abilities_Registry](https://developer.wordpress.org/reference/classes/wp_abilities_registry/) ## 󠀁[Methods](https://developer.wordpress.org/reference/classes/wp_ability/?output_format=md#methods)󠁿 | Name | Description | | [WP_Ability::__construct](https://developer.wordpress.org/reference/classes/wp_ability/__construct/) | Constructor. | | [WP_Ability::__sleep](https://developer.wordpress.org/reference/classes/wp_ability/__sleep/) | Sleep magic method. | | [WP_Ability::__wakeup](https://developer.wordpress.org/reference/classes/wp_ability/__wakeup/) | Wakeup magic method. | | [WP_Ability::check_permissions](https://developer.wordpress.org/reference/classes/wp_ability/check_permissions/) | Checks whether the ability has the necessary permissions. | | [WP_Ability::do_execute](https://developer.wordpress.org/reference/classes/wp_ability/do_execute/) | Executes the ability callback. | | [WP_Ability::execute](https://developer.wordpress.org/reference/classes/wp_ability/execute/) | Executes the ability after input validation and running a permission check. | | [WP_Ability::get_category](https://developer.wordpress.org/reference/classes/wp_ability/get_category/) | Retrieves the ability category for the ability. | | [WP_Ability::get_description](https://developer.wordpress.org/reference/classes/wp_ability/get_description/) | Retrieves the detailed description for the ability. | | [WP_Ability::get_input_schema](https://developer.wordpress.org/reference/classes/wp_ability/get_input_schema/) | Retrieves the input schema for the ability. | | [WP_Ability::get_label](https://developer.wordpress.org/reference/classes/wp_ability/get_label/) | Retrieves the human-readable label for the ability. | | [WP_Ability::get_meta](https://developer.wordpress.org/reference/classes/wp_ability/get_meta/) | Retrieves the metadata for the ability. | | [WP_Ability::get_meta_item](https://developer.wordpress.org/reference/classes/wp_ability/get_meta_item/) | Retrieves a specific metadata item for the ability. | | [WP_Ability::get_name](https://developer.wordpress.org/reference/classes/wp_ability/get_name/) | Retrieves the name of the ability, with its namespace. | | [WP_Ability::get_output_schema](https://developer.wordpress.org/reference/classes/wp_ability/get_output_schema/) | Retrieves the output schema for the ability. | | [WP_Ability::invoke_callback](https://developer.wordpress.org/reference/classes/wp_ability/invoke_callback/) | Invokes a callable, ensuring the input is passed through only if the input schema is defined. | | [WP_Ability::normalize_input](https://developer.wordpress.org/reference/classes/wp_ability/normalize_input/) | Normalizes the input for the ability, applying the default value from the input schema when needed. | | [WP_Ability::prepare_properties](https://developer.wordpress.org/reference/classes/wp_ability/prepare_properties/) | Prepares and validates the properties used to instantiate the ability. | | [WP_Ability::validate_input](https://developer.wordpress.org/reference/classes/wp_ability/validate_input/) | Validates input data against the input schema. | | [WP_Ability::validate_output](https://developer.wordpress.org/reference/classes/wp_ability/validate_output/) | Validates output data against the output schema. | ## 󠀁[Source](https://developer.wordpress.org/reference/classes/wp_ability/?output_format=md#source)󠁿 ```php class WP_Ability { /** * The default value for the `show_in_rest` meta. * * @since 6.9.0 * @var bool */ protected const DEFAULT_SHOW_IN_REST = false; /** * The default ability annotations. * They are not guaranteed to provide a faithful description of ability behavior. * * @since 6.9.0 * @var array */ protected static $default_annotations = array( // If true, the ability does not modify its environment. 'readonly' => null, /* * If true, the ability may perform destructive updates to its environment. * If false, the ability performs only additive updates. */ 'destructive' => null, /* * If true, calling the ability repeatedly with the same arguments will have no additional effect * on its environment. */ 'idempotent' => null, ); /** * The name of the ability, with its namespace. * Example: `my-plugin/my-ability`. * * @since 6.9.0 * @var string */ protected $name; /** * The human-readable ability label. * * @since 6.9.0 * @var string */ protected $label; /** * The detailed ability description. * * @since 6.9.0 * @var string */ protected $description; /** * The ability category. * * @since 6.9.0 * @var string */ protected $category; /** * The optional ability input schema. * * @since 6.9.0 * @var array */ protected $input_schema = array(); /** * The optional ability output schema. * * @since 6.9.0 * @var array */ protected $output_schema = array(); /** * The ability execute callback. * * @since 6.9.0 * @var callable( mixed $input= ): (mixed|WP_Error) */ protected $execute_callback; /** * The optional ability permission callback. * * @since 6.9.0 * @var callable( mixed $input= ): (bool|WP_Error) */ protected $permission_callback; /** * The optional ability metadata. * * @since 6.9.0 * @var array */ protected $meta; /** * Constructor. * * Do not use this constructor directly. Instead, use the `wp_register_ability()` function. * * @access private * * @since 6.9.0 * * @see wp_register_ability() * * @param string $name The name of the ability, with its namespace. * @param array $args { * An associative array of arguments for the ability. * * @type string $label The human-readable label for the ability. * @type string $description A detailed description of what the ability does. * @type string $category The ability category slug this ability belongs to. * @type callable $execute_callback A callback function to execute when the ability is invoked. * Receives optional mixed input and returns mixed result or WP_Error. * @type callable $permission_callback A callback function to check permissions before execution. * Receives optional mixed input and returns bool or WP_Error. * @type array $input_schema Optional. JSON Schema definition for the ability's input. * @type array $output_schema Optional. JSON Schema definition for the ability's output. * @type array $meta { * Optional. Additional metadata for the ability. * * @type array $annotations { * Optional. Semantic annotations describing the ability's behavioral characteristics. * These annotations are hints for tooling and documentation. * * @type bool|null $readonly Optional. If true, the ability does not modify its environment. * @type bool|null $destructive Optional. If true, the ability may perform destructive updates to its environment. * If false, the ability performs only additive updates. * @type bool|null $idempotent Optional. If true, calling the ability repeatedly with the same arguments * will have no additional effect on its environment. * } * @type bool $show_in_rest Optional. Whether to expose this ability in the REST API. Default false. * } * } */ public function __construct( string $name, array $args ) { $this->name = $name; $properties = $this->prepare_properties( $args ); foreach ( $properties as $property_name => $property_value ) { if ( ! property_exists( $this, $property_name ) ) { _doing_it_wrong( __METHOD__, sprintf( /* translators: %s: Property name. */ __( 'Property "%1$s" is not a valid property for ability "%2$s". Please check the %3$s class for allowed properties.' ), '' . esc_html( $property_name ) . '', '' . esc_html( $this->name ) . '', '' . __CLASS__ . '' ), '6.9.0' ); continue; } $this->$property_name = $property_value; } } /** * Prepares and validates the properties used to instantiate the ability. * * Errors are thrown as exceptions instead of WP_Errors to allow for simpler handling and overloading. They are then * caught and converted to a WP_Error when by WP_Abilities_Registry::register(). * * @since 6.9.0 * * @see WP_Abilities_Registry::register() * * @param array $args { * An associative array of arguments used to instantiate the ability class. * * @type string $label The human-readable label for the ability. * @type string $description A detailed description of what the ability does. * @type string $category The ability category slug this ability belongs to. * @type callable $execute_callback A callback function to execute when the ability is invoked. * Receives optional mixed input and returns mixed result or WP_Error. * @type callable $permission_callback A callback function to check permissions before execution. * Receives optional mixed input and returns bool or WP_Error. * @type array $input_schema Optional. JSON Schema definition for the ability's input. Required if ability accepts an input. * @type array $output_schema Optional. JSON Schema definition for the ability's output. * @type array $meta { * Optional. Additional metadata for the ability. * * @type array $annotations { * Optional. Semantic annotations describing the ability's behavioral characteristics. * These annotations are hints for tooling and documentation. * * @type bool|null $readonly Optional. If true, the ability does not modify its environment. * @type bool|null $destructive Optional. If true, the ability may perform destructive updates to its environment. * If false, the ability performs only additive updates. * @type bool|null $idempotent Optional. If true, calling the ability repeatedly with the same arguments * will have no additional effect on its environment. * } * @type bool $show_in_rest Optional. Whether to expose this ability in the REST API. Default false. * } * } * @return array { * An associative array of arguments with validated and prepared properties for the ability class. * * @type string $label The human-readable label for the ability. * @type string $description A detailed description of what the ability does. * @type string $category The ability category slug this ability belongs to. * @type callable $execute_callback A callback function to execute when the ability is invoked. * Receives optional mixed input and returns mixed result or WP_Error. * @type callable $permission_callback A callback function to check permissions before execution. * Receives optional mixed input and returns bool or WP_Error. * @type array $input_schema Optional. JSON Schema definition for the ability's input. * @type array $output_schema Optional. JSON Schema definition for the ability's output. * @type array $meta { * Additional metadata for the ability. * * @type array $annotations { * Semantic annotations describing the ability's behavioral characteristics. * These annotations are hints for tooling and documentation. * * @type bool|null $readonly If true, the ability does not modify its environment. * @type bool|null $destructive If true, the ability may perform destructive updates to its environment. * If false, the ability performs only additive updates. * @type bool|null $idempotent If true, calling the ability repeatedly with the same arguments * will have no additional effect on its environment. * } * @type bool $show_in_rest Whether to expose this ability in the REST API. Default false. * } * } * @throws InvalidArgumentException if an argument is invalid. */ protected function prepare_properties( array $args ): array { // Required args must be present and of the correct type. if ( empty( $args['label'] ) || ! is_string( $args['label'] ) ) { throw new InvalidArgumentException( __( 'The ability properties must contain a `label` string.' ) ); } if ( empty( $args['description'] ) || ! is_string( $args['description'] ) ) { throw new InvalidArgumentException( __( 'The ability properties must contain a `description` string.' ) ); } if ( empty( $args['category'] ) || ! is_string( $args['category'] ) ) { throw new InvalidArgumentException( __( 'The ability properties must contain a `category` string.' ) ); } if ( empty( $args['execute_callback'] ) || ! is_callable( $args['execute_callback'] ) ) { throw new InvalidArgumentException( __( 'The ability properties must contain a valid `execute_callback` function.' ) ); } if ( empty( $args['permission_callback'] ) || ! is_callable( $args['permission_callback'] ) ) { throw new InvalidArgumentException( __( 'The ability properties must provide a valid `permission_callback` function.' ) ); } // Optional args only need to be of the correct type if they are present. if ( isset( $args['input_schema'] ) && ! is_array( $args['input_schema'] ) ) { throw new InvalidArgumentException( __( 'The ability properties should provide a valid `input_schema` definition.' ) ); } if ( isset( $args['output_schema'] ) && ! is_array( $args['output_schema'] ) ) { throw new InvalidArgumentException( __( 'The ability properties should provide a valid `output_schema` definition.' ) ); } if ( isset( $args['meta'] ) && ! is_array( $args['meta'] ) ) { throw new InvalidArgumentException( __( 'The ability properties should provide a valid `meta` array.' ) ); } if ( isset( $args['meta']['annotations'] ) && ! is_array( $args['meta']['annotations'] ) ) { throw new InvalidArgumentException( __( 'The ability meta should provide a valid `annotations` array.' ) ); } if ( isset( $args['meta']['show_in_rest'] ) && ! is_bool( $args['meta']['show_in_rest'] ) ) { throw new InvalidArgumentException( __( 'The ability meta should provide a valid `show_in_rest` boolean.' ) ); } // Set defaults for optional meta. $args['meta'] = wp_parse_args( $args['meta'] ?? array(), array( 'annotations' => static::$default_annotations, 'show_in_rest' => self::DEFAULT_SHOW_IN_REST, ) ); $args['meta']['annotations'] = wp_parse_args( $args['meta']['annotations'], static::$default_annotations ); return $args; } /** * Retrieves the name of the ability, with its namespace. * Example: `my-plugin/my-ability`. * * @since 6.9.0 * * @return string The ability name, with its namespace. */ public function get_name(): string { return $this->name; } /** * Retrieves the human-readable label for the ability. * * @since 6.9.0 * * @return string The human-readable ability label. */ public function get_label(): string { return $this->label; } /** * Retrieves the detailed description for the ability. * * @since 6.9.0 * * @return string The detailed description for the ability. */ public function get_description(): string { return $this->description; } /** * Retrieves the ability category for the ability. * * @since 6.9.0 * * @return string The ability category for the ability. */ public function get_category(): string { return $this->category; } /** * Retrieves the input schema for the ability. * * @since 6.9.0 * * @return array The input schema for the ability. */ public function get_input_schema(): array { return $this->input_schema; } /** * Retrieves the output schema for the ability. * * @since 6.9.0 * * @return array The output schema for the ability. */ public function get_output_schema(): array { return $this->output_schema; } /** * Retrieves the metadata for the ability. * * @since 6.9.0 * * @return array The metadata for the ability. */ public function get_meta(): array { return $this->meta; } /** * Retrieves a specific metadata item for the ability. * * @since 6.9.0 * * @param string $key The metadata key to retrieve. * @param mixed $default_value Optional. The default value to return if the metadata item is not found. Default `null`. * @return mixed The value of the metadata item, or the default value if not found. */ public function get_meta_item( string $key, $default_value = null ) { return array_key_exists( $key, $this->meta ) ? $this->meta[ $key ] : $default_value; } /** * Normalizes the input for the ability, applying the default value from the input schema when needed. * * When no input is provided and the input schema is defined with a top-level `default` key, this method returns * the value of that key. If the input schema does not define a `default`, or if the input schema is empty, * this method returns null. If input is provided, it is returned as-is. * * @since 6.9.0 * * @param mixed $input Optional. The raw input provided for the ability. Default `null`. * @return mixed The same input, or the default from schema, or `null` if default not set. */ public function normalize_input( $input = null ) { if ( null !== $input ) { return $input; } $input_schema = $this->get_input_schema(); if ( ! empty( $input_schema ) && array_key_exists( 'default', $input_schema ) ) { return $input_schema['default']; } return null; } /** * Validates input data against the input schema. * * @since 6.9.0 * * @param mixed $input Optional. The input data to validate. Default `null`. * @return true|WP_Error Returns true if valid or the WP_Error object if validation fails. */ public function validate_input( $input = null ) { $input_schema = $this->get_input_schema(); if ( empty( $input_schema ) ) { if ( null === $input ) { return true; } return new WP_Error( 'ability_missing_input_schema', sprintf( /* translators: %s ability name. */ __( 'Ability "%s" does not define an input schema required to validate the provided input.' ), esc_html( $this->name ) ) ); } $valid_input = rest_validate_value_from_schema( $input, $input_schema, 'input' ); if ( is_wp_error( $valid_input ) ) { return new WP_Error( 'ability_invalid_input', sprintf( /* translators: %1$s ability name, %2$s error message. */ __( 'Ability "%1$s" has invalid input. Reason: %2$s' ), esc_html( $this->name ), $valid_input->get_error_message() ) ); } return true; } /** * Invokes a callable, ensuring the input is passed through only if the input schema is defined. * * @since 6.9.0 * * @param callable $callback The callable to invoke. * @param mixed $input Optional. The input data for the ability. Default `null`. * @return mixed The result of the callable execution. */ protected function invoke_callback( callable $callback, $input = null ) { $args = array(); if ( ! empty( $this->get_input_schema() ) ) { $args[] = $input; } return $callback( ...$args ); } /** * Checks whether the ability has the necessary permissions. * * Please note that input is not automatically validated against the input schema. * Use `validate_input()` method to validate input before calling this method if needed. * * @since 6.9.0 * * @see validate_input() * * @param mixed $input Optional. The valid input data for permission checking. Default `null`. * @return bool|WP_Error Whether the ability has the necessary permission. */ public function check_permissions( $input = null ) { if ( ! is_callable( $this->permission_callback ) ) { return new WP_Error( 'ability_invalid_permission_callback', /* translators: %s ability name. */ sprintf( __( 'Ability "%s" does not have a valid permission callback.' ), esc_html( $this->name ) ) ); } return $this->invoke_callback( $this->permission_callback, $input ); } /** * Executes the ability callback. * * @since 6.9.0 * * @param mixed $input Optional. The input data for the ability. Default `null`. * @return mixed|WP_Error The result of the ability execution, or WP_Error on failure. */ protected function do_execute( $input = null ) { if ( ! is_callable( $this->execute_callback ) ) { return new WP_Error( 'ability_invalid_execute_callback', /* translators: %s ability name. */ sprintf( __( 'Ability "%s" does not have a valid execute callback.' ), esc_html( $this->name ) ) ); } return $this->invoke_callback( $this->execute_callback, $input ); } /** * Validates output data against the output schema. * * @since 6.9.0 * * @param mixed $output The output data to validate. * @return true|WP_Error Returns true if valid, or a WP_Error object if validation fails. */ 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; } /** * Executes the ability after input validation and running a permission check. * Before returning the return value, it also validates the output. * * @since 6.9.0 * * @param mixed $input Optional. The input data for the ability. Default `null`. * @return mixed|WP_Error The result of the ability execution, or WP_Error on failure. */ public function execute( $input = null ) { $input = $this->normalize_input( $input ); $is_valid = $this->validate_input( $input ); if ( is_wp_error( $is_valid ) ) { return $is_valid; } $has_permissions = $this->check_permissions( $input ); if ( true !== $has_permissions ) { if ( is_wp_error( $has_permissions ) ) { // Don't leak the permission check error to someone without the correct perms. _doing_it_wrong( __METHOD__, esc_html( $has_permissions->get_error_message() ), '6.9.0' ); } return new WP_Error( 'ability_invalid_permissions', /* translators: %s ability name. */ sprintf( __( 'Ability "%s" does not have necessary permission.' ), esc_html( $this->name ) ) ); } /** * Fires before an ability gets executed, after input validation and permissions check. * * @since 6.9.0 * * @param string $ability_name The name of the ability. * @param mixed $input The input data for the ability. */ do_action( 'wp_before_execute_ability', $this->name, $input ); $result = $this->do_execute( $input ); if ( is_wp_error( $result ) ) { return $result; } $is_valid = $this->validate_output( $result ); if ( is_wp_error( $is_valid ) ) { return $is_valid; } /** * Fires immediately after an ability finished executing. * * @since 6.9.0 * * @param string $ability_name The name of the ability. * @param mixed $input The input data for the ability. * @param mixed $result The result of the ability execution. */ do_action( 'wp_after_execute_ability', $this->name, $input, $result ); return $result; } /** * Wakeup magic method. * * @since 6.9.0 * @throws LogicException If the ability object is unserialized. * This is a security hardening measure to prevent unserialization of the ability. */ public function __wakeup(): void { throw new LogicException( __CLASS__ . ' should never be unserialized.' ); } /** * Sleep magic method. * * @since 6.9.0 * @throws LogicException If the ability object is serialized. * This is a security hardening measure to prevent serialization of the ability. */ public function __sleep(): array { throw new LogicException( __CLASS__ . ' should never be serialized.' ); } } ``` [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#L21) [View on GitHub](https://github.com/WordPress/wordpress-develop/blob/6.9.4/src/wp-includes/abilities-api/class-wp-ability.php#L21-L678) ## 󠀁[Changelog](https://developer.wordpress.org/reference/classes/wp_ability/?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%2F) before being able to contribute a note or feedback.