Add the Title Generation feature base

composer.json

@@ -7,7 +7,7 @@
     "automattic/jetpack-autoloader": "^5.0",
     "ext-json": "*",
     "php": ">=7.4",
-    "wordpress/abilities-api": "^0.4.0-rc",
+    "wordpress/abilities-api": "^0.4.0",
     "wordpress/mcp-adapter": "dev-trunk",
     "wordpress/wp-ai-client": "dev-trunk"
   },

includes/Abilities/Title_Generation.php

@@ -0,0 +1,172 @@
+<?php
+/**
+ * Title generation WordPress Ability implementation.
+ *
+ * @package WordPress\AI
+ */
+
+declare( strict_types=1 );
+
+namespace WordPress\AI\Abilities;
+
+use WP_Error;
+use WordPress\AI\Abstracts\Abstract_Ability;
+
+/**
+ * Title generation WordPress Ability.
+ *
+ * @since 0.1.0
+ */
+class Title_Generation extends Abstract_Ability {
+
+	/**
+	 * Returns the category of the ability.
+	 *
+	 * @since 0.1.0
+	 *
+	 * @return string The category of the ability.
+	 */
+	protected function category(): string {
+		return 'ai-experiments'; // TODO: add a reusable way to get the category slug?
+	}
+
+	/**
+	 * Returns the input schema of the ability.
+	 *
+	 * @since 0.1.0
+	 *
+	 * @return array<string, mixed> The input schema of the ability.
+	 */
+	protected function input_schema(): array {
+		return array(
+			'type'       => 'object',
+			'properties' => array(
+				'content' => array(
+					'type'              => 'string',
+					'sanitize_callback' => 'sanitize_text_field',
+					'description'       => esc_html__( 'Content to generate title suggestions for.', 'ai' ),
+				),
+				'post_id' => array(
+					'type'              => 'integer',
+					'sanitize_callback' => 'absint',
+					'description'       => esc_html__( 'Content from this post will be used to generate title suggestions. This overrides the content parameter if both are provided.', 'ai' ),
+				),
+				'n'       => array(
+					'type'              => 'integer',
+					'minimum'           => 1,
+					'maximum'           => 10,
+					'sanitize_callback' => 'absint',
+					'description'       => esc_html__( 'Number of titles to generate', 'ai' ),
+				),
+			),
+		);
+	}
+
+	/**
+	 * Returns the output schema of the ability.
+	 *
+	 * @since 0.1.0
+	 *
+	 * @return array<string, mixed> The output schema of the ability.
+	 */
+	protected function output_schema(): array {
+		return array(
+			'type'       => 'object',
+			'properties' => array(
+				'titles' => array(
+					'type'        => 'array',
+					'description' => esc_html__( 'Generated title suggestions.', 'ai' ),
+					'items'       => array(
+						'type' => 'string',
+					),
+				),
+			),
+		);
+	}
+
+	/**
+	 * Executes the ability with the given input arguments.
+	 *
+	 * @since 0.1.0
+	 *
+	 * @param mixed $input The input arguments to the ability.
+	 * @return mixed|\WP_Error The result of the ability execution, or a WP_Error on failure.
+	 */
+	protected function execute_callback( $input ) {
+		// Default arguments.
+		$args = wp_parse_args(
+			$input,
+			array(
+				'content' => null,
+				'post_id' => null,
+				'n'       => 1,
+			),
+		);
+
+		// If a post ID is provided, ensure the post exists before using its' content.
+		if ( $args['post_id'] ) {
+			$post = get_post( $args['post_id'] );
+
+			if ( ! $post ) {
+				return new WP_Error(
+					'post_not_found',
+					/* translators: %d: Post ID. */
+					sprintf( esc_html__( 'Post with ID %d not found.', 'ai' ), absint( $args['post_id'] ) )
+				);
+			}
+
+			$args['content'] = $post->post_content;
+		}
+
+		// If we have no content, return an error.
+		if ( ! $args['content'] ) {
+			return new WP_Error(
+				'content_not_provided',
+				esc_html__( 'Content is required to generate title suggestions.', 'ai' )
+			);
+		}
+
+		// TODO: Implement the title generation logic.
+
+		return array(
+			'name'        => $this->get_name(),
+			'label'       => $this->get_label(),
+			'description' => $this->get_description(),
+			'content'     => wp_kses_post( $args['content'] ),
+			'post_id'     => absint( $args['post_id'] ) ?? esc_html__( 'Not provided', 'ai' ),
+			'n'           => absint( $args['n'] ),
+		);
+	}
+
+	/**
+	 * Returns the permission callback of the ability.
+	 *
+	 * @since 0.1.0
+	 *
+	 * @param mixed $args The input arguments to the ability.
+	 * @return bool|\WP_Error True if the user has permission, WP_Error otherwise.
+	 */
+	protected function permission_callback( $args ) {
+		if ( ! current_user_can( 'edit_posts' ) ) {
+			return new WP_Error(
+				'insufficient_capabilities',
+				esc_html__( 'You do not have permission to generate titles.', 'ai' )
+			);
+		}
+
+		return true;
+	}
+
+	/**
+	 * Returns the meta of the ability.
+	 *
+	 * @since 0.1.0
+	 *
+	 * @return array<string, mixed> The meta of the ability.
+	 */
+	protected function meta(): array {
+		return array(
+			'show_in_rest' => true,
+		);
+	}
+}

includes/Abstracts/Abstract_Ability.php

@@ -0,0 +1,100 @@
+<?php
+/**
+ * Abstract Ability base class.
+ *
+ * @package WordPress\AI\Abstracts
+ */
+
+declare( strict_types=1 );
+
+namespace WordPress\AI\Abstracts;
+
+use WP_Ability;
+
+/**
+ * Base implementation for a WordPress Ability.
+ *
+ * @since 0.1.0
+ */
+abstract class Abstract_Ability extends WP_Ability {
+
+	/**
+	 * Constructor.
+	 *
+	 * @since 0.1.0
+	 *
+	 * @param string              $name       The name of the ability.
+	 * @param array<string,mixed> $properties The properties of the ability. Must include `label`.
+	 */
+	public function __construct( string $name, array $properties = array() ) {
+		parent::__construct(
+			$name,
+			array(
+				'label'               => $properties['label'] ?? '',
+				'description'         => $properties['description'] ?? '',
+				'category'            => $this->category(),
+				'input_schema'        => $this->input_schema(),
+				'output_schema'       => $this->output_schema(),
+				'execute_callback'    => array( $this, 'execute_callback' ),
+				'permission_callback' => array( $this, 'permission_callback' ),
+				'meta'                => $this->meta(),
+			)
+		);
+	}
+
+	/**
+	 * Returns the category of the ability.
+	 *
+	 * @since 0.1.0
+	 *
+	 * @return string The category of the ability.
+	 */
+	abstract protected function category(): string;
+
+	/**
+	 * Returns the input schema of the ability.
+	 *
+	 * @since 0.1.0
+	 *
+	 * @return array<string, mixed> The input schema of the ability.
+	 */
+	abstract protected function input_schema(): array;
+
+	/**
+	 * Returns the output schema of the ability.
+	 *
+	 * @since 0.1.0
+	 *
+	 * @return array<string, mixed> The output schema of the ability.
+	 */
+	abstract protected function output_schema(): array;
+
+	/**
+	 * Executes the ability with the given input arguments.
+	 *
+	 * @since 0.1.0
+	 *
+	 * @param mixed $input The input arguments to the ability.
+	 * @return mixed|\WP_Error The result of the ability execution, or a WP_Error on failure.
+	 */
+	abstract protected function execute_callback( $input );
+
+	/**
+	 * Checks whether the current user has permission to execute the ability with the given input arguments.
+	 *
+	 * @since 0.1.0
+	 *
+	 * @param mixed $input The input arguments to the ability.
+	 * @return bool|\WP_Error True if the user has permission, WP_Error otherwise.
+	 */
+	abstract protected function permission_callback( $input );
+
+	/**
+	 * Returns the meta of the ability.
+	 *
+	 * @since 0.1.0
+	 *
+	 * @return array<string, mixed> The meta of the ability.
+	 */
+	abstract protected function meta(): array;
+}

includes/Feature_Loader.php

@@ -102,7 +102,8 @@ public function register_default_features(): void {
 	 */
 	private function get_default_features(): array {
 		$feature_classes = array(
-			'WordPress\AI\Features\Example_Feature\Example_Feature',
+			\WordPress\AI\Features\Example_Feature\Example_Feature::class,
+			\WordPress\AI\Features\Title_Generation\Title_Generation::class,
 		);
 
 		/**

includes/Features/Title_Generation/Title_Generation.php

@@ -0,0 +1,61 @@
+<?php
+/**
+ * Title generation feature implementation.
+ *
+ * @package WordPress\AI
+ */
+
+declare( strict_types=1 );
+
+namespace WordPress\AI\Features\Title_Generation;
+
+use WordPress\AI\Abilities\Title_Generation as Title_Generation_Ability;
+use WordPress\AI\Abstracts\Abstract_Feature;
+
+/**
+ * Title generation feature.
+ *
+ * @since 0.1.0
+ */
+class Title_Generation extends Abstract_Feature {
+
+	/**
+	 * {@inheritDoc}
+	 *
+	 * @since 0.1.0
+	 *
+	 * @return array{id: string, label: string, description: string} Feature metadata.
+	 */
+	protected function load_feature_metadata(): array {
+		return array(
+			'id'          => 'title-generation',
+			'label'       => __( 'Title Generation', 'ai' ),
+			'description' => __( 'Generates title suggestions from content', 'ai' ),
+		);
+	}
+
+	/**
+	 * {@inheritDoc}
+	 *
+	 * @since 0.1.0
+	 */
+	public function register(): void {
+		add_action( 'wp_abilities_api_init', array( $this, 'register_abilities' ) );
+	}
+
+	/**
+	 * Registers any needed abilities.
+	 *
+	 * @since 0.1.0
+	 */
+	public function register_abilities(): void {
+		wp_register_ability(
+			'ai/' . $this->get_id(),
+			array(
+				'label'         => $this->get_label(),
+				'description'   => $this->get_description(),
+				'ability_class' => Title_Generation_Ability::class,
+			),
+		);
+	}
+}