diff --git a/includes/class-psa-search-handler.php b/includes/class-psa-search-handler.php
new file mode 100644
index 0000000..ef778e0
--- /dev/null
+++ b/includes/class-psa-search-handler.php
@@ -0,0 +1,211 @@
+<?php
+/**
+ * AJAX search handler and peptide generation workflow.
+ *
+ * What: Orchestrates the AJAX search flow — checks existing results, handles
+ *       pending retries, validates new peptide names, creates placeholders,
+ *       and schedules background generation.
+ * Who calls it: PSA_Search::init() registers the AJAX action that invokes ajax_search().
+ * Dependencies: PSA_Config, PSA_AI_Generator, PSA_Search (for search_peptides/find_pending).
+ *
+ * @package PeptideSearchAI
+ * @since   2.6.0
+ * @see     includes/class-psa-search.php         — Core search and cache logic.
+ * @see     includes/class-psa-ai-generator.php   — Peptide validation and content generation.
+ */
+declare( strict_types=1 );
+
+if ( ! defined( 'ABSPATH' ) ) {
+	exit;
+}
+
+class PSA_Search_Handler {
+
+	/**
+	 * AJAX handler: search for peptides.
+	 *
+	 * Orchestrates: search → pending check → rate limit → validate → generate.
+	 * Side effects: nonce check, JSON response, may create posts and schedule cron.
+	 */
+	public static function ajax_search(): void {
+		check_ajax_referer( 'psa_search_nonce', 'nonce' );
+
+		$query = isset( $_GET['q'] ) ? sanitize_text_field( wp_unslash( $_GET['q'] ) ) : '';
+
+		if ( mb_strlen( $query ) < PSA_Config::MIN_QUERY_LENGTH || mb_strlen( $query ) > PSA_Config::MAX_QUERY_LENGTH ) {
+			wp_send_json_error( 'Search query must be between ' . PSA_Config::MIN_QUERY_LENGTH . ' and ' . PSA_Config::MAX_QUERY_LENGTH . ' characters.' );
+		}
+
+		// 1. Search existing published peptides.
+		$results = PSA_Search::search_peptides( $query );
+
+		if ( ! empty( $results['results'] ) ) {
+			wp_send_json_success( array( 'status' => 'found', 'data' => $results ) );
+			return;
+		}
+
+		// 2. Check if already pending — handles retries if timed out.
+		$pending = PSA_Search::find_pending_peptide( $query );
+		if ( $pending ) {
+			self::handle_pending_retry( $pending );
+			return;
+		}
+
+		// 3. Check rate limit before attempting new generation.
+		if ( ! self::check_rate_limit() ) {
+			wp_send_json_success( array( 'status' => 'rate_limited', 'message' => 'Too many requests. Please try again later.' ) );
+			return;
+		}
+
+		// 4. Validate and generate.
+		self::handle_new_generation( $query );
+	}
+
+	/**
+	 * Handle a pending peptide — retry if timed out, else return pending status.
+	 *
+	 * Side effects: may update post meta, schedule cron, JSON response.
+	 *
+	 * @param WP_Post $pending The pending post.
+	 */
+	private static function handle_pending_retry( $pending ): void {
+		$started     = (int) get_post_meta( $pending->ID, 'psa_generation_started', true );
+		$retry_count = (int) get_post_meta( $pending->ID, 'psa_generation_attempts', true );
+		$timed_out   = $started && ( time() - $started ) > PSA_Config::PENDING_TIMEOUT;
+
+		if ( $timed_out ) {
+			if ( $retry_count >= PSA_Config::MAX_GENERATION_RETRIES ) {
+				error_log( 'PSA: Max retries (' . PSA_Config::MAX_GENERATION_RETRIES . ') exceeded for "' . $pending->post_title . '" (post ' . $pending->ID . '). Marking as failed.' );
+				update_post_meta( $pending->ID, 'psa_source', 'failed' );
+				update_post_meta( $pending->ID, 'psa_generation_error', 'Generation failed after ' . PSA_Config::MAX_GENERATION_RETRIES . ' attempts.' );
+				wp_send_json_success( array(
+					'status'  => 'invalid',
+					'message' => 'We were unable to generate content for this peptide. Please try again later.',
+				) );
+				return;
+			}
+
+			error_log( 'PSA: Retrying stale pending peptide ' . $pending->post_title . ' (post ' . $pending->ID . ', attempt ' . ( $retry_count + 1 ) . '/' . PSA_Config::MAX_GENERATION_RETRIES . ')' );
+			update_post_meta( $pending->ID, 'psa_generation_started', time() );
+			update_post_meta( $pending->ID, 'psa_generation_attempts', $retry_count + 1 );
+			self::schedule_background_generation( $pending->ID, $pending->post_title );
+		}
+
+		wp_send_json_success( array( 'status' => 'pending', 'peptide_name' => $pending->post_title ) );
+	}
+
+	/**
+	 * Check rate limit for AJAX generation requests.
+	 *
+	 * Uses dual-layer caching (transient + object cache) for resilience.
+	 *
+	 * @return bool True if under limit.
+	 */
+	private static function check_rate_limit(): bool {
+		$ip       = psa_get_client_ip();
+		$rate_key = 'psa_rate_' . md5( $ip );
+
+		$count_transient = (int) get_transient( $rate_key );
+		$count_cache     = (int) wp_cache_get( $rate_key, 'psa_rate_limits' );
+		$count           = max( $count_transient, $count_cache );
+
+		return $count < PSA_Config::AJAX_RATE_LIMIT;
+	}
+
+	/**
+	 * Handle a new generation request — validate, create placeholder, and schedule.
+	 *
+	 * Side effects: AI validation call, post creation, rate limit update, cron schedule, JSON response.
+	 *
+	 * @param string $query The search query (peptide name).
+	 */
+	private static function handle_new_generation( string $query ): void {
+		// Global daily generation cap to prevent cost overruns.
+		$daily_key   = 'psa_daily_gen_' . gmdate( 'Y-m-d' );
+		$daily_count = (int) get_transient( $daily_key );
+		if ( $daily_count >= PSA_Config::DAILY_GENERATION_CAP ) {
+			wp_send_json_success( array(
+				'status'  => 'rate_limited',
+				'message' => 'Our system has reached its daily limit for adding new peptides. Please try again tomorrow.',
+			) );
+			return;
+		}
+
+		$validation = PSA_AI_Generator::validate_peptide_name( $query );
+
+		if ( is_wp_error( $validation ) ) {
+			error_log( 'PSA: Validation error for "' . $query . '": ' . $validation->get_error_message() );
+			wp_send_json_success( array( 'status' => 'invalid', 'message' => 'Could not verify this peptide name.' ) );
+		}
+
+		if ( empty( $validation['is_valid'] ) ) {
+			wp_send_json_success( array(
+				'status'  => 'invalid',
+				'message' => $validation['reason'] ?? 'This does not appear to be a recognized peptide.',
+			) );
+		}
+
+		// Valid peptide — increment rate limit and create placeholder.
+		$ip       = psa_get_client_ip();
+		$rate_key = 'psa_rate_' . md5( $ip );
+		$count    = (int) get_transient( $rate_key );
+		set_transient( $rate_key, $count + 1, HOUR_IN_SECONDS );
+		wp_cache_set( $rate_key, $count + 1, 'psa_rate_limits', HOUR_IN_SECONDS );
+
+		$canonical_name = sanitize_text_field( $validation['canonical_name'] ?? $query );
+		$placeholder_id = self::create_pending_placeholder( $canonical_name );
+
+		if ( is_wp_error( $placeholder_id ) ) {
+			wp_send_json_error( 'Failed to create peptide entry. Please try again.' );
+		}
+
+		// Increment global daily generation counter.
+		set_transient( $daily_key, $daily_count + 1, DAY_IN_SECONDS );
+
+		error_log( 'PSA: Scheduling async generation for "' . $canonical_name . '" (post ' . $placeholder_id . ')' );
+		self::schedule_background_generation( $placeholder_id, $canonical_name );
+
+		wp_send_json_success( array( 'status' => 'pending', 'peptide_name' => $canonical_name ) );
+	}
+
+	/**
+	 * Create a placeholder draft post for the pending peptide.
+	 *
+	 * @param string $peptide_name Canonical peptide name.
+	 * @return int|WP_Error Post ID or error.
+	 */
+	public static function create_pending_placeholder( string $peptide_name ) {
+		$post_id = wp_insert_post(
+			array(
+				'post_type'    => 'peptide',
+				'post_title'   => $peptide_name,
+				'post_content' => '',
+				'post_status'  => 'draft',
+				'post_author'  => psa_get_admin_user_id(),
+			),
+			true
+		);
+
+		if ( ! is_wp_error( $post_id ) ) {
+			update_post_meta( $post_id, 'psa_source', 'pending' );
+			update_post_meta( $post_id, 'psa_generation_started', time() );
+			do_action( 'psa_peptide_created', $post_id, $peptide_name );
+		}
+
+		return $post_id;
+	}
+
+	/**
+	 * Schedule background generation using WP-Cron (non-blocking).
+	 *
+	 * @param int    $post_id      Placeholder post ID.
+	 * @param string $peptide_name Peptide to research.
+	 */
+	public static function schedule_background_generation( int $post_id, string $peptide_name ): void {
+		$args = array( $post_id, $peptide_name );
+		if ( ! wp_next_scheduled( 'psa_generate_peptide_background', $args ) ) {
+			wp_schedule_single_event( time(), 'psa_generate_peptide_background', $args );
+		}
+		spawn_cron();
+	}
+}
diff --git a/includes/class-psa-search.php b/includes/class-psa-search.php
index 85582fa..42bbc84 100755
--- a/includes/class-psa-search.php
+++ b/includes/class-psa-search.php
@@ -1,13 +1,13 @@
 <?php
 /**
- * Handles AJAX search, the [peptide_search] shortcode, and the REST API endpoint.
+ * Core search, caching, shortcode rendering, and REST endpoint for peptides.
  *
- * What: Core search logic — AJAX handler, REST endpoint, shortcode rendering, cache management.
- * Who calls it: WordPress AJAX/REST hooks, shortcode parser, save_post_peptide action.
- * Dependencies: PSA_Config, PSA_AI_Generator, WordPress AJAX/REST/shortcode APIs.
+ * What: Shortcode rendering, REST search, transient caching, result formatting.
+ * Who calls it: WordPress shortcode parser, REST API, PSA_Search_Handler (for search_peptides).
+ * Dependencies: PSA_Config, PSA_Search_Handler (for AJAX/generation workflow).
  *
  * @package PeptideSearchAI
- * @see     includes/class-psa-ai-generator.php
+ * @see     includes/class-psa-search-handler.php — AJAX handler and generation workflow.
  * @see     includes/class-psa-config.php
  */
 declare( strict_types=1 );
@@ -18,66 +18,45 @@ if ( ! defined( 'ABSPATH' ) ) {
 
 class PSA_Search {
 
-	/**
-	 * Static counter for unique shortcode instance IDs.
-	 *
-	 * @var int
-	 */
+	/** @var int Static counter for unique shortcode instance IDs. */
 	private static $instance_count = 0;
 
 	public static function init(): void {
 		add_shortcode( 'peptide_search', array( __CLASS__, 'render_search_form' ) );
-		add_action( 'wp_ajax_psa_search', array( __CLASS__, 'ajax_search' ) );
-		add_action( 'wp_ajax_nopriv_psa_search', array( __CLASS__, 'ajax_search' ) );
+		add_action( 'wp_ajax_psa_search', array( 'PSA_Search_Handler', 'ajax_search' ) );
+		add_action( 'wp_ajax_nopriv_psa_search', array( 'PSA_Search_Handler', 'ajax_search' ) );
 		add_action( 'rest_api_init', array( __CLASS__, 'register_rest_routes' ) );
-		// Cache invalidation when a peptide is saved.
 		add_action( 'save_post_peptide', array( __CLASS__, 'invalidate_search_cache' ) );
 	}
 
 	/**
 	 * Get the current cache generation counter.
 	 *
-	 * The generation counter is used to invalidate all psa_search_* caches
-	 * without expensive DELETE queries. When a peptide is saved, we increment
-	 * the generation, causing all searches to use a new cache key and thus
-	 * bypass stale results. Old transients expire naturally via their 6hr TTL.
+	 * Used to invalidate all psa_search_* caches without expensive DELETE queries.
+	 * When a peptide is saved, we increment the generation, causing all searches
+	 * to use a new cache key and bypass stale results.
 	 *
-	 * @return int The current generation counter (default 0).
+	 * @return int Current generation counter.
 	 */
 	private static function get_cache_generation(): int {
-		$gen = (int) get_option( 'psa_search_cache_gen', 0 );
-		return $gen;
+		return (int) get_option( 'psa_search_cache_gen', 0 );
 	}
 
 	/**
 	 * Invalidate all search caches by incrementing the generation counter.
 	 *
-	 * Instead of a costly DELETE query that removes all psa_search_* transients,
-	 * this method increments a generation counter. All future search_peptides()
-	 * calls will use a new cache key (that includes the generation number),
-	 * effectively invalidating all old caches. Old transients expire naturally
-	 * via their 6hr TTL.
-	 *
-	 * Performance: O(1) option update vs. O(n) database DELETE query.
-	 * Use flush_all_search_caches() only for manual cache clearing from admin.
+	 * O(1) option update vs. O(n) DELETE query.
 	 *
 	 * @param int $post_id The post ID being saved.
 	 */
 	public static function invalidate_search_cache( int $post_id ): void {
-		$current_gen = self::get_cache_generation();
-		update_option( 'psa_search_cache_gen', $current_gen + 1 );
+		update_option( 'psa_search_cache_gen', self::get_cache_generation() + 1 );
 	}
 
 	/**
 	 * Flush all search caches immediately via DELETE query.
 	 *
-	 * This is a manual cache-clearing method for admin use (e.g., from settings),
-	 * not called on every peptide save. Use invalidate_search_cache() for that.
-	 *
-	 * WARNING: Expensive operation — performs a DELETE query on wp_options.
-	 * Only use when absolutely necessary (e.g., maintenance, manual admin actions).
-	 *
-	 * @return void
+	 * WARNING: Expensive — only use for manual admin actions, not on every save.
 	 */
 	public static function flush_all_search_caches(): void {
 		global $wpdb;
@@ -89,10 +68,7 @@ class PSA_Search {
 		);
 	}
 
-	/**
-	 * Register REST API routes for external/headless access.
-	 * Note: REST route only returns existing published results — it does NOT trigger generation.
-	 */
+	/** Register REST API route for external/headless access. */
 	public static function register_rest_routes(): void {
 		register_rest_route(
 			'peptides/v1',
@@ -118,44 +94,27 @@ class PSA_Search {
 	 * REST search callback — returns published peptides only (no generation trigger).
 	 *
 	 * Uses dual-layer rate limiting (transient + object cache) for resilience.
-	 * If Redis/Memcached evicts the transient, we fall back to the object cache.
-	 *
-	 * Limitation: IP spoofing or cache server restart could bypass the limit.
-	 * For high-traffic deployments, consider a custom DB table with persistent
-	 * rate limit tracking (e.g., wp_psa_rate_limits with indexed IP + timestamp).
 	 *
 	 * @param WP_REST_Request $request The REST request.
 	 * @return WP_REST_Response
 	 */
 	public static function rest_search( $request ) {
-		// Rate limiting: max REST_RATE_LIMIT requests per IP per hour.
-		// Uses dual-layer caching (transient + object cache) for resilience.
 		$ip       = psa_get_client_ip();
 		$rate_key = 'psa_rest_rate_' . md5( $ip );
 
-		// Check transient first.
 		$count_transient = (int) get_transient( $rate_key );
-
-		// Check object cache as secondary source for resilience.
-		$count_cache = (int) wp_cache_get( $rate_key, 'psa_rate_limits' );
-
-		// Use the highest count from either source.
-		$count = max( $count_transient, $count_cache );
+		$count_cache     = (int) wp_cache_get( $rate_key, 'psa_rate_limits' );
+		$count           = max( $count_transient, $count_cache );
 
 		if ( $count >= PSA_Config::REST_RATE_LIMIT ) {
-			return new WP_REST_Response(
-				array( 'error' => 'Rate limit exceeded. Please try again later.' ),
-				429
-			);
+			return new WP_REST_Response( array( 'error' => 'Rate limit exceeded. Please try again later.' ), 429 );
 		}
 
-		// Update both transient and object cache for resilience.
 		set_transient( $rate_key, $count + 1, HOUR_IN_SECONDS );
 		wp_cache_set( $rate_key, $count + 1, 'psa_rate_limits', HOUR_IN_SECONDS );
 
 		$query = $request->get_param( 'q' );
 
-		// Max input length validation.
 		if ( mb_strlen( $query ) > PSA_Config::MAX_QUERY_LENGTH ) {
 			return new WP_REST_Response(
 				array( 'error' => 'Search query must not exceed ' . PSA_Config::MAX_QUERY_LENGTH . ' characters.' ),
@@ -163,16 +122,13 @@ class PSA_Search {
 			);
 		}
 
-		$results = self::search_peptides( $query );
-		return new WP_REST_Response( $results, 200 );
+		return new WP_REST_Response( self::search_peptides( $query ), 200 );
 	}
 
 	/**
 	 * Render the [peptide_search] shortcode.
 	 *
-	 * Uses class-based selectors (no IDs) to support multiple shortcode instances
-	 * on the same page (e.g., hero section + search overlay). Each instance is
-	 * independently functional via scoped JS initialization.
+	 * Uses class-based selectors (no IDs) to support multiple instances per page.
 	 *
 	 * @param array $atts Shortcode attributes.
 	 * @return string HTML output.
@@ -182,9 +138,7 @@ class PSA_Search {
 		$instance = self::$instance_count;
 
 		$atts = shortcode_atts(
-			array(
-				'placeholder' => 'Search for a peptide (e.g., BPC-157, Thymosin Beta-4)...',
-			),
+			array( 'placeholder' => 'Search for a peptide (e.g., BPC-157, Thymosin Beta-4)...' ),
 			$atts,
 			'peptide_search'
 		);
@@ -225,210 +179,10 @@ class PSA_Search {
 	}
 
 	/**
-	 * AJAX handler: search for peptides.
-	 * Orchestrates complete workflow: search, pending check, rate limiting, validation, generation.
-	 *
-	 * @return void Exits with wp_send_json_* responses.
-	 */
-	public static function ajax_search(): void {
-		check_ajax_referer( 'psa_search_nonce', 'nonce' );
-
-		$query = isset( $_GET['q'] ) ? sanitize_text_field( wp_unslash( $_GET['q'] ) ) : '';
-
-		// Validate query length using PSA_Config constants.
-		if ( mb_strlen( $query ) < PSA_Config::MIN_QUERY_LENGTH || mb_strlen( $query ) > PSA_Config::MAX_QUERY_LENGTH ) {
-			wp_send_json_error( 'Search query must be between ' . PSA_Config::MIN_QUERY_LENGTH . ' and ' . PSA_Config::MAX_QUERY_LENGTH . ' characters.' );
-		}
-
-		// 1. Search existing published peptides.
-		$results = self::search_peptides( $query );
-
-		if ( ! empty( $results['results'] ) ) {
-			wp_send_json_success(
-				array(
-					'status' => 'found',
-					'data'   => $results,
-				)
-			);
-			return;
-		}
-
-		// 2. Check if already pending — handles retries if timed out.
-		$pending = self::find_pending_peptide( $query );
-		if ( $pending ) {
-			self::handle_pending_retry( $pending );
-			return; // handle_pending_retry() exits with wp_send_json_success()
-		}
-
-		// 3. Check rate limit before attempting new generation.
-		if ( ! self::check_rate_limit() ) {
-			wp_send_json_success(
-				array(
-					'status'  => 'rate_limited',
-					'message' => 'Too many requests. Please try again later.',
-				)
-			);
-			return;
-		}
-
-		// 4. Validate and generate.
-		self::handle_new_generation( $query );
-		return; // handle_new_generation() exits with wp_send_json_*()
-	}
-
-	/**
-	 * Handle a pending peptide — retry if timed out, else return pending status.
-	 *
-	 * @param WP_Post $pending The pending post.
-	 * @return void Exits with wp_send_json_success().
-	 */
-	private static function handle_pending_retry( $pending ): void {
-		$started     = (int) get_post_meta( $pending->ID, 'psa_generation_started', true );
-		$retry_count = (int) get_post_meta( $pending->ID, 'psa_generation_attempts', true );
-		$timed_out   = $started && ( time() - $started ) > PSA_Config::PENDING_TIMEOUT;
-
-		if ( $timed_out ) {
-			if ( $retry_count >= PSA_Config::MAX_GENERATION_RETRIES ) {
-				// Max retries exceeded — mark as failed.
-				error_log( 'PSA: Max retries (' . PSA_Config::MAX_GENERATION_RETRIES . ') exceeded for "' . $pending->post_title . '" (post ' . $pending->ID . '). Marking as failed.' );
-				update_post_meta( $pending->ID, 'psa_source', 'failed' );
-				update_post_meta( $pending->ID, 'psa_generation_error', 'Generation failed after ' . PSA_Config::MAX_GENERATION_RETRIES . ' attempts.' );
-				wp_send_json_success(
-					array(
-						'status'  => 'invalid',
-						'message' => 'We were unable to generate content for this peptide. Please try again later.',
-					)
-				);
-				return;
-			}
-
-			// Retry generation.
-			error_log( 'PSA: Retrying stale pending peptide ' . $pending->post_title . ' (post ' . $pending->ID . ', attempt ' . ( $retry_count + 1 ) . '/' . PSA_Config::MAX_GENERATION_RETRIES . ')' );
-			update_post_meta( $pending->ID, 'psa_generation_started', time() );
-			update_post_meta( $pending->ID, 'psa_generation_attempts', $retry_count + 1 );
-			self::schedule_background_generation( $pending->ID, $pending->post_title );
-		}
-
-		wp_send_json_success(
-			array(
-				'status'       => 'pending',
-				'peptide_name' => $pending->post_title,
-			)
-		);
-	}
-
-	/**
-	 * Check rate limit for AJAX generation requests.
-	 *
-	 * Uses dual-layer caching (transient + object cache) for resilience.
-	 * If Redis/Memcached evicts the transient, we fall back to the object cache.
-	 * If either source reports the limit exceeded, the request is rate-limited.
-	 *
-	 * Limitation: IP spoofing or cache server restart could bypass the limit.
-	 * For high-traffic deployments, consider a custom DB table with persistent
-	 * rate limit tracking (e.g., wp_psa_rate_limits with indexed IP + timestamp).
-	 *
-	 * @return bool True if under limit, false if limit exceeded.
-	 */
-	private static function check_rate_limit(): bool {
-		$ip       = psa_get_client_ip();
-		$rate_key = 'psa_rate_' . md5( $ip );
-
-		// Check transient first.
-		$count_transient = (int) get_transient( $rate_key );
-
-		// Check object cache as secondary source for resilience.
-		$count_cache = (int) wp_cache_get( $rate_key, 'psa_rate_limits' );
-
-		// Use the highest count from either source.
-		$count = max( $count_transient, $count_cache );
-
-		return $count < PSA_Config::AJAX_RATE_LIMIT;
-	}
-
-	/**
-	 * Handle a new generation request — validate, create placeholder, and schedule generation.
-	 *
-	 * @param string $query The search query (peptide name).
-	 * @return void Exits with wp_send_json_* responses.
-	 */
-	private static function handle_new_generation( string $query ): void {
-		// Global daily generation cap to prevent cost overruns.
-		$daily_key   = 'psa_daily_gen_' . gmdate( 'Y-m-d' );
-		$daily_count = (int) get_transient( $daily_key );
-		if ( $daily_count >= PSA_Config::DAILY_GENERATION_CAP ) {
-			wp_send_json_success(
-				array(
-					'status'  => 'rate_limited',
-					'message' => 'Our system has reached its daily limit for adding new peptides. Please try again tomorrow.',
-				)
-			);
-			return;
-		}
-
-		// Validate peptide name via AI.
-		$validation = PSA_AI_Generator::validate_peptide_name( $query );
-
-		if ( is_wp_error( $validation ) ) {
-			error_log( 'PSA: Validation error for "' . $query . '": ' . $validation->get_error_message() );
-			wp_send_json_success(
-				array(
-					'status'  => 'invalid',
-					'message' => 'Could not verify this peptide name.',
-				)
-			);
-		}
-
-		if ( empty( $validation['is_valid'] ) ) {
-			wp_send_json_success(
-				array(
-					'status'  => 'invalid',
-					'message' => $validation['reason'] ?? 'This does not appear to be a recognized peptide.',
-				)
-			);
-		}
-
-		// It's a real peptide — increment rate limit and create placeholder.
-		// Update both transient and object cache for resilience.
-		$ip       = psa_get_client_ip();
-		$rate_key = 'psa_rate_' . md5( $ip );
-		$count    = (int) get_transient( $rate_key );
-		set_transient( $rate_key, $count + 1, HOUR_IN_SECONDS );
-		wp_cache_set( $rate_key, $count + 1, 'psa_rate_limits', HOUR_IN_SECONDS );
-
-		$canonical_name = sanitize_text_field( $validation['canonical_name'] ?? $query );
-		$placeholder_id = self::create_pending_placeholder( $canonical_name );
-
-		if ( is_wp_error( $placeholder_id ) ) {
-			wp_send_json_error( 'Failed to create peptide entry. Please try again.' );
-		}
-
-		// Increment global daily generation counter.
-		$daily_key   = 'psa_daily_gen_' . gmdate( 'Y-m-d' );
-		$daily_count = (int) get_transient( $daily_key );
-		set_transient( $daily_key, $daily_count + 1, DAY_IN_SECONDS );
-
-		// Schedule async background generation.
-		error_log( 'PSA: Scheduling async generation for "' . $canonical_name . '" (post ' . $placeholder_id . ')' );
-		self::schedule_background_generation( $placeholder_id, $canonical_name );
-
-		wp_send_json_success(
-			array(
-				'status'       => 'pending',
-				'peptide_name' => $canonical_name,
-			)
-		);
-	}
-
-	/**
-	 * Find an existing pending peptide post by name.
-	 *
-	 * Performs a multi-table query to locate pending draft posts by title or alias.
-	 * Queries the posts table joined with postmeta for 'psa_source' = 'pending' status,
-	 * plus LEFT JOIN on postmeta for aliases. Returns the most recent match.
+	 * Find an existing pending peptide post by name or alias.
 	 *
 	 * @param string $query Search term (peptide name or alias).
-	 * @return WP_Post|null Pending post object or null if not found.
+	 * @return WP_Post|null Pending post or null.
 	 */
 	public static function find_pending_peptide( string $query ) {
 		global $wpdb;
@@ -458,62 +212,16 @@ class PSA_Search {
 	}
 
 	/**
-	 * Create a placeholder draft post so we can track the pending state.
+	 * Core search — queries CPT by title and aliases (published only).
 	 *
-	 * @param string $peptide_name The canonical peptide name.
-	 * @return int|WP_Error Post ID or error.
-	 */
-	public static function create_pending_placeholder( string $peptide_name ) {
-		$post_id = wp_insert_post(
-			array(
-				'post_type'    => 'peptide',
-				'post_title'   => $peptide_name,
-				'post_content' => '',
-				'post_status'  => 'draft',
-				'post_author'  => psa_get_admin_user_id(),
-			),
-			true
-		);
-
-		if ( ! is_wp_error( $post_id ) ) {
-			update_post_meta( $post_id, 'psa_source', 'pending' );
-			update_post_meta( $post_id, 'psa_generation_started', time() );
-			// Allow developers to hook into placeholder creation.
-			do_action( 'psa_peptide_created', $post_id, $peptide_name );
-		}
-
-		return $post_id;
-	}
-
-	/**
-	 * Schedule background generation using WP-Cron (non-blocking).
-	 *
-	 * @param int    $post_id      The placeholder post ID.
-	 * @param string $peptide_name The peptide to research.
-	 */
-	public static function schedule_background_generation( int $post_id, string $peptide_name ): void {
-		$args = array( $post_id, $peptide_name );
-		if ( ! wp_next_scheduled( 'psa_generate_peptide_background', $args ) ) {
-			wp_schedule_single_event( time(), 'psa_generate_peptide_background', $args );
-		}
-		spawn_cron();
-	}
-
-	/**
-	 * Core search logic — queries CPT by title and aliases (published only).
-	 * Includes transient caching and batch post/meta priming to avoid N+1 queries.
-	 *
-	 * Cache key includes the generation counter, so invalidate_search_cache()
-	 * can purge all caches by incrementing the counter (O(1) vs. expensive DELETE).
+	 * Includes transient caching with generation-counter invalidation.
 	 *
 	 * @param string $query Search term.
-	 * @return array { results: array, total: int, query: string }
+	 * @return array{results: array, total: int, query: string}
 	 */
 	public static function search_peptides( string $query ): array {
 		global $wpdb;
 
-		// Check transient cache first.
-		// Include generation counter in cache key for fast invalidation.
 		$cache_key = 'psa_search_' . self::get_cache_generation() . '_' . md5( sanitize_text_field( $query ) );
 		$cached    = get_transient( $cache_key );
 		if ( false !== $cached ) {
@@ -539,7 +247,6 @@ class PSA_Search {
 		);
 
 		if ( ! empty( $post_ids ) ) {
-			// Prime the WordPress object cache for all posts and their meta in batch.
 			_prime_post_caches( $post_ids );
 			update_meta_cache( 'post', $post_ids );
 		}
@@ -549,19 +256,11 @@ class PSA_Search {
 			$results[] = self::format_peptide( (int) $id );
 		}
 
-		$response = array(
-			'results' => $results,
-			'total'   => count( $results ),
-			'query'   => $query,
-		);
+		$response = array( 'results' => $results, 'total' => count( $results ), 'query' => $query );
 
-		// Cache results for 6 hours.
 		set_transient( $cache_key, $response, 6 * HOUR_IN_SECONDS );
 
-		// Allow filtering of search results before return.
-		$response = apply_filters( 'psa_search_results', $response, $query );
-
-		return $response;
+		return apply_filters( 'psa_search_results', $response, $query );
 	}
 
 	/**
@@ -587,4 +286,15 @@ class PSA_Search {
 			'source'            => get_post_meta( $post->ID, 'psa_source', true ),
 		);
 	}
+
+	// ── Backward-compatible proxies ─────────────────────────────────────
+
+	/** @see PSA_Search_Handler::ajax_search() */
+	public static function ajax_search(): void { PSA_Search_Handler::ajax_search(); }
+
+	/** @see PSA_Search_Handler::create_pending_placeholder() */
+	public static function create_pending_placeholder( string $peptide_name ) { return PSA_Search_Handler::create_pending_placeholder( $peptide_name ); }
+
+	/** @see PSA_Search_Handler::schedule_background_generation() */
+	public static function schedule_background_generation( int $post_id, string $peptide_name ): void { PSA_Search_Handler::schedule_background_generation( $post_id, $peptide_name ); }
 }
diff --git a/peptide-search-ai.php b/peptide-search-ai.php
index e1661c3..883f338 100755
--- a/peptide-search-ai.php
+++ b/peptide-search-ai.php
@@ -23,6 +23,7 @@ define( 'PSA_PLUGIN_FILE', __FILE__ );
 require_once PSA_PLUGIN_DIR . 'includes/class-psa-config.php';
 require_once PSA_PLUGIN_DIR . 'includes/class-psa-encryption.php';
 require_once PSA_PLUGIN_DIR . 'includes/class-psa-post-type.php';
+require_once PSA_PLUGIN_DIR . 'includes/class-psa-search-handler.php';
 require_once PSA_PLUGIN_DIR . 'includes/class-psa-search.php';
 require_once PSA_PLUGIN_DIR . 'includes/class-psa-cost-tracker.php';
 require_once PSA_PLUGIN_DIR . 'includes/class-psa-openrouter.php';