OpenAI in WordPress and WooCommerce: Rapidtextai and custom AI tools

function my_ai_completion( string $prompt, string $model = 'gpt-4o-mini', int $max_tokens = 800 ): string|WP_Error {
    $body = [
        'model'       => $model,
        'messages'    => [
            [ 'role' => 'system', 'content' => 'You are a helpful product copywriter. Answer only from the provided context.' ],
            [ 'role' => 'user',   'content' => $prompt ],
        ],
        'max_tokens'  => $max_tokens,
        'temperature' => 0.7,
    ];

    $response = wp_remote_post( 'https://api.openai.com/v1/chat/completions', [
        'timeout' => 60,
        'headers' => [
            'Authorization' => 'Bearer ' . MY_OPENAI_KEY,
            'Content-Type'  => 'application/json',
        ],
        'body'    => wp_json_encode( $body ),
    ] );

    if ( is_wp_error( $response ) ) {
        return $response;
    }

    $code = wp_remote_retrieve_response_code( $response );
    $data = json_decode( wp_remote_retrieve_body( $response ), true );

    if ( 429 === $code ) {
        // Rate limited — schedule a retry rather than failing the request.
        as_schedule_single_action( time() + 60, 'my_ai_retry', [ $prompt, $model ] );
        return new WP_Error( 'ai_rate_limited', 'Rate limited; queued for retry.' );
    }

    if ( 200 !== $code ) {
        return new WP_Error( 'ai_api_error', $data['error']['message'] ?? 'Unknown API error' );
    }

    $choice = $data['choices'][0] ?? null;
    if ( ! $choice ) {
        return new WP_Error( 'ai_empty', 'No completion returned.' );
    }

    if ( 'length' === ( $choice['finish_reason'] ?? '' ) ) {
        return new WP_Error( 'ai_truncated', 'Output hit max_tokens; increase the limit or split the prompt.' );
    }

    return trim( $choice['message']['content'] );
}

The finish_reason check is the most important line, because without it truncated output looks like a successful completion and gets saved as a broken description.

add_action( 'my_generate_product_description', function ( int $product_id ): void {
    $product = wc_get_product( $product_id );
    if ( ! $product ) {
        return;
    }

    // Never overwrite a human edit.
    if ( '1' === get_post_meta( $product_id, '_description_human_edited', true ) ) {
        return;
    }

    $prompt = sprintf(
        "Write a 120-word product description for: %s. Category: %s. Price: %s. Tone: %s. Return only the description.",
        $product->get_name(),
        wp_strip_all_tags( wc_get_product_category_list( $product_id ) ),
        $product->get_price(),
        get_option( 'my_brand_tone', 'professional and warm' )
    );

    $result = my_ai_completion( $prompt );
    if ( is_wp_error( $result ) ) {
        update_post_meta( $product_id, '_ai_description_error', $result->get_error_message() );
        return;
    }

    // Store as a draft meta field; the editor publishes deliberately.
    update_post_meta( $product_id, '_ai_description_draft', wp_kses_post( $result ) );
    update_post_meta( $product_id, '_ai_description_generated_at', time() );
}, 10, 1 );

Writing to a meta draft instead of $product->set_description() is what makes the tool safe to run in bulk, since a human still has the final click.

function my_ai_user_can_generate( int $user_id ): bool {
    $cap  = (int) get_option( 'my_ai_monthly_cap_' . my_ai_user_role( $user_id ), 100 );
    $used = (int) get_user_meta( $user_id, '_ai_generations_' . gmdate( 'Ym' ), true );
    return $used < $cap;
}

function my_ai_record_generation( int $user_id ): void {
    $key  = '_ai_generations_' . gmdate( 'Ym' );
    $used = (int) get_user_meta( $user_id, $key, true );
    update_user_meta( $user_id, $key, $used + 1 );
}

The cap is keyed on year-month, so it resets by itself each month without a cron job.