diff --git a/ARCHITECTURE.md b/ARCHITECTURE.md
index d2d26da..aa2aa91 100755
--- a/ARCHITECTURE.md
+++ b/ARCHITECTURE.md
@@ -105,7 +105,9 @@ prautoblogger/
 │
 ├── includes/
 │   ├── class-prautoblogger.php        # Main orchestrator — registers all hooks, delegates execution
-│   ├── class-executor.php             # Cron/AJAX handlers, generation lock, model registry access
+│   ├── class-executor.php             # Cron handlers, generation AJAX (start + status), model registry
+│   ├── class-ajax-handlers.php        # Non-generation AJAX: images, models, test connections
+│   ├── class-generation-lock.php      # DB-level atomic mutex for single-writer generation
 │   ├── class-activator.php            # Activation: create DB tables, set defaults, schedule cron
 │   ├── class-deactivator.php          # Deactivation: clear cron, cleanup transients
 │   ├── class-autoloader.php           # PSR-4-style autoloader for plugin classes
@@ -236,6 +238,53 @@ The widget CSS (`posts-widget.css`) uses the Peptide Starter theme's CSS custom
 
 ---
 
+## Background Generation Flow (v0.3.0)
+
+The "Generate Now" button runs the pipeline in a background WP-Cron process to avoid
+Hostinger's 120-second LiteSpeed connection timeout. The frontend polls for status.
+
+```
+┌──────────────────────────────┐
+│  Admin clicks "Generate Now" │  admin.js sends AJAX to on_ajax_generate_now()
+└────────────┬─────────────────┘
+             │  Handler returns immediately (< 1 second):
+             │  1. Writes "running" transient with started timestamp
+             │  2. Schedules one-shot cron: prautoblogger_manual_generation
+             │  3. Fires non-blocking loopback to wp-cron.php
+             │  4. Returns JSON success to browser
+             ▼
+┌──────────────────────────────┐
+│  admin.js starts polling     │  setInterval every 5 seconds
+│  on_ajax_generation_status() │  Shows stage text + spinner
+└────────────┬─────────────────┘
+             │
+             ▼ (separate PHP process)
+┌──────────────────────────────┐
+│  on_manual_generation()      │  WP-Cron fires this in a new request
+│  (class-executor.php)        │  1. ignore_user_abort(true) — survives HTTP kill
+│                              │  2. set_time_limit(300)
+│                              │  3. Acquires PRAutoBlogger_Generation_Lock
+│                              │  4. Runs PRAutoBlogger_Pipeline_Runner::run()
+│                              │     (pipeline broadcasts stage updates to transient)
+│                              │  5. Writes final result to transient
+│                              │  6. Releases lock
+└────────────┬─────────────────┘
+             │
+             ▼
+┌──────────────────────────────┐
+│  Poller detects completion   │  Reads transient: status = 'complete' or 'error'
+│  Shows result message        │  Resets button to idle state
+└──────────────────────────────┘
+```
+
+**Fallback detection:** If Hostinger kills the PHP process before it updates the
+transient (despite `ignore_user_abort`), the status endpoint detects the orphan after
+180 seconds by checking for recently-created posts with `_prautoblogger_run_id` meta.
+It also releases any stale generation lock. After 600 seconds (STATUS_TTL), it gives
+up unconditionally and reports a timeout.
+
+---
+
 ## Database Schema
 
 ### Custom Tables
diff --git a/includes/class-ajax-handlers.php b/includes/class-ajax-handlers.php
new file mode 100644
index 0000000..63283cd
--- /dev/null
+++ b/includes/class-ajax-handlers.php
@@ -0,0 +1,145 @@
+<?php
+declare(strict_types=1);
+
+/**
+ * AJAX endpoint handlers for PRAutoBlogger admin actions.
+ *
+ * What: Handles image generation, model registry, and connection test AJAX requests.
+ * Who calls it: PRAutoBlogger registers wp_ajax hooks that delegate to methods here.
+ * Dependencies: PRAutoBlogger_Image_Pipeline, PRAutoBlogger_Source_Collector,
+ *               PRAutoBlogger_OpenRouter_Provider, PRAutoBlogger_Reddit_Provider,
+ *               PRAutoBlogger_OpenRouter_Model_Registry, PRAutoBlogger_Logger.
+ *
+ * @see class-prautoblogger.php — Hook registration that wires these handlers.
+ * @see class-executor.php      — Generation-related AJAX lives there (generate_now, status).
+ */
+class PRAutoBlogger_Ajax_Handlers {
+
+	/** @var PRAutoBlogger_OpenRouter_Model_Registry Model registry instance (shared with Executor). */
+	private PRAutoBlogger_OpenRouter_Model_Registry $model_registry;
+
+	/**
+	 * @param PRAutoBlogger_OpenRouter_Model_Registry $model_registry Shared model registry.
+	 */
+	public function __construct( PRAutoBlogger_OpenRouter_Model_Registry $model_registry ) {
+		$this->model_registry = $model_registry;
+	}
+
+	/**
+	 * AJAX handler: generate images for existing posts that lack them.
+	 *
+	 * Accepts a `post_id` parameter. Generates Image A (article-driven) and
+	 * sets it as the featured image. Useful for retroactively adding images
+	 * to posts published before image generation was enabled/fixed.
+	 *
+	 * Side effects: image provider API call, media library write, post meta update.
+	 */
+	public function on_ajax_generate_image(): void {
+		check_ajax_referer( 'prautoblogger_generate_image', 'nonce' );
+
+		if ( ! current_user_can( 'manage_options' ) ) {
+			wp_send_json_error( [ 'message' => __( 'Insufficient permissions.', 'prautoblogger' ) ], 403 );
+			return;
+		}
+
+		// Image generation can take 20-30s on Cloudflare Workers AI.
+		// phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged
+		@set_time_limit( 120 );
+
+		$post_id = isset( $_POST['post_id'] ) ? absint( $_POST['post_id'] ) : 0;
+		if ( 0 === $post_id ) {
+			wp_send_json_error( [ 'message' => __( 'Missing post_id parameter.', 'prautoblogger' ) ] );
+			return;
+		}
+
+		$post = get_post( $post_id );
+		if ( ! $post ) {
+			wp_send_json_error( [ 'message' => sprintf( __( 'Post %d not found.', 'prautoblogger' ), $post_id ) ] );
+			return;
+		}
+
+		try {
+			$pipeline     = new PRAutoBlogger_Image_Pipeline();
+			$article_data = [
+				'post_title'   => $post->post_title,
+				'post_content' => $post->post_content,
+			];
+
+			// Retrieve original source IDs from post meta so Image B can generate
+			// a source-driven prompt even on retroactive regeneration.
+			$source_ids_json = get_post_meta( $post_id, '_prautoblogger_source_ids', true );
+			$source_ids      = is_string( $source_ids_json ) ? json_decode( $source_ids_json, true ) : [];
+			$source_data     = ( new PRAutoBlogger_Source_Collector() )->get_source_data_for_image(
+				is_array( $source_ids ) ? array_map( 'absint', $source_ids ) : []
+			);
+
+			// The pipeline sets featured image and Image B meta internally.
+			$result = $pipeline->generate_and_attach_images( $post_id, $article_data, $source_data );
+
+			wp_send_json_success( $result );
+		} catch ( \Throwable $e ) {
+			PRAutoBlogger_Logger::instance()->error(
+				sprintf( 'Retroactive image gen %s for post %d: %s', get_class( $e ), $post_id, $e->getMessage() ),
+				'image_pipeline'
+			);
+			wp_send_json_error( [ 'message' => $e->getMessage() ] );
+		}
+	}
+
+	/**
+	 * AJAX handler: return the model registry for the admin model picker.
+	 *
+	 * Returns the full cached model list. If the registry is empty, triggers
+	 * a refresh first. Called by the model-picker.js popup.
+	 *
+	 * Side effects: may trigger an OpenRouter API call if registry is empty.
+	 */
+	public function on_ajax_get_models(): void {
+		check_ajax_referer( 'prautoblogger_get_models', 'nonce' );
+
+		if ( ! current_user_can( 'manage_options' ) ) {
+			wp_send_json_error( [ 'message' => __( 'Insufficient permissions.', 'prautoblogger' ) ], 403 );
+			return;
+		}
+
+		$models = $this->model_registry->get_models();
+
+		// Auto-refresh if the registry has never been populated.
+		if ( empty( $models ) ) {
+			$this->model_registry->refresh( true );
+			$models = $this->model_registry->get_models();
+		}
+
+		wp_send_json_success( $models );
+	}
+
+	/**
+	 * AJAX handler: test API connections (OpenRouter, Reddit).
+	 *
+	 * Accepts a `service` parameter: 'openrouter', 'reddit', or 'all'.
+	 *
+	 * Side effects: API calls to OpenRouter and/or Reddit to validate credentials.
+	 */
+	public function on_ajax_test_connection(): void {
+		check_ajax_referer( 'prautoblogger_test_connection', 'nonce' );
+		if ( ! current_user_can( 'manage_options' ) ) {
+			wp_send_json_error( [ 'message' => __( 'Insufficient permissions.', 'prautoblogger' ) ], 403 );
+			return;
+		}
+
+		$service = isset( $_POST['service'] ) ? sanitize_text_field( wp_unslash( $_POST['service'] ) ) : '';
+		$results = [];
+
+		if ( 'openrouter' === $service || 'all' === $service ) {
+			$results['openrouter'] = ( new PRAutoBlogger_OpenRouter_Provider() )->validate_credentials_detailed();
+		}
+		if ( 'reddit' === $service || 'all' === $service ) {
+			$reddit  = new PRAutoBlogger_Reddit_Provider();
+			$is_ok   = $reddit->validate_credentials();
+			$results['reddit'] = $is_ok
+				? [ 'status' => 'ok', 'message' => __( 'Reddit source available (RSS primary, .json fallback).', 'prautoblogger' ) ]
+				: [ 'status' => 'error', 'message' => __( 'Reddit sources unreachable (both RSS and .json failed).', 'prautoblogger' ) ];
+		}
+		wp_send_json_success( $results );
+	}
+}
diff --git a/includes/class-executor.php b/includes/class-executor.php
index e219939..e5973ed 100644
--- a/includes/class-executor.php
+++ b/includes/class-executor.php
@@ -2,21 +2,28 @@
 declare(strict_types=1);
 
 /**
- * Execution handlers for generation, metrics collection, and AJAX actions.
+ * Execution handlers for content generation and metrics collection.
  *
- * What: Cron event handlers, AJAX endpoints, atomic generation lock, model registry access.
- * Who calls it: PRAutoBlogger registers hooks that delegate to methods on this class.
- * Dependencies: PRAutoBlogger_Pipeline_Runner, PRAutoBlogger_Metrics_Collector,
- *               PRAutoBlogger_Logger, PRAutoBlogger_OpenRouter_Provider, PRAutoBlogger_Reddit_Provider.
+ * What: Cron handlers, generation AJAX (start + status polling), model registry.
+ * Who calls it: PRAutoBlogger registers hooks that delegate here.
+ * Dependencies: Pipeline_Runner, Metrics_Collector, Generation_Lock, Logger, Model_Registry.
  *
- * @see class-prautoblogger.php       — Hook registration that wires these handlers.
- * @see core/class-pipeline-runner.php — Actual generation pipeline.
+ * @see class-prautoblogger.php          — Hook registration that wires these handlers.
+ * @see core/class-pipeline-runner.php    — Actual generation pipeline.
+ * @see class-generation-lock.php         — DB mutex extracted from this class.
+ * @see class-ajax-handlers.php           — Non-generation AJAX endpoints (images, models, test).
  */
 class PRAutoBlogger_Executor {
 
 	/** @var PRAutoBlogger_OpenRouter_Model_Registry|null Lazy-loaded singleton. */
 	private ?PRAutoBlogger_OpenRouter_Model_Registry $model_registry = null;
 
+	/** Transient key for background generation status. */
+	private const STATUS_TRANSIENT = 'prautoblogger_generation_status';
+
+	/** How long to keep the result available for polling (seconds). */
+	private const STATUS_TTL = 600;
+
 	/**
 	 * Handle the daily generation cron event.
 	 * Uses an atomic DB mutex to prevent overlapping runs.
@@ -27,7 +34,7 @@ class PRAutoBlogger_Executor {
 		// Refresh model registry before lock — stuck lock shouldn't block refresh.
 		do_action( 'prautoblogger_refresh_model_registry', false );
 
-		if ( ! $this->acquire_generation_lock() ) {
+		if ( ! PRAutoBlogger_Generation_Lock::acquire() ) {
 			PRAutoBlogger_Logger::instance()->info( 'Daily generation skipped: already running (lock held).', 'scheduler' );
 			return;
 		}
@@ -40,7 +47,7 @@ class PRAutoBlogger_Executor {
 				'scheduler'
 			);
 		} finally {
-			$this->release_generation_lock();
+			PRAutoBlogger_Generation_Lock::release();
 		}
 	}
 
@@ -59,12 +66,6 @@ class PRAutoBlogger_Executor {
 		}
 	}
 
-	/** Transient key for background generation status. */
-	private const STATUS_TRANSIENT = 'prautoblogger_generation_status';
-
-	/** How long to keep the result available for polling (seconds). */
-	private const STATUS_TTL = 600;
-
 	/**
 	 * AJAX handler: kick off manual generation as a background cron job.
 	 *
@@ -84,7 +85,7 @@ class PRAutoBlogger_Executor {
 
 		$force = isset( $_POST['force'] ) && '1' === $_POST['force'];
 		if ( $force ) {
-			$this->release_generation_lock();
+			PRAutoBlogger_Generation_Lock::release();
 			delete_transient( self::STATUS_TRANSIENT );
 		}
 
@@ -114,9 +115,6 @@ class PRAutoBlogger_Executor {
 
 		// Spawn the cron immediately via a non-blocking loopback request
 		// so we don't depend on the next visitor to trigger it.
-		// Some hosts (including Hostinger) set DISABLE_WP_CRON = true and
-		// rely on an external cron runner. spawn_cron() respects that flag
-		// and may no-op, so we also fire a direct loopback as a fallback.
 		spawn_cron();
 
 		// Direct non-blocking loopback to wp-cron.php — ensures the event
@@ -155,7 +153,7 @@ class PRAutoBlogger_Executor {
 		// phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged
 		@set_time_limit( 300 );
 
-		if ( ! $this->acquire_generation_lock() ) {
+		if ( ! PRAutoBlogger_Generation_Lock::acquire() ) {
 			set_transient( self::STATUS_TRANSIENT, [
 				'status'  => 'error',
 				'message' => __( 'Could not acquire generation lock. Another run may be in progress.', 'prautoblogger' ),
@@ -164,7 +162,6 @@ class PRAutoBlogger_Executor {
 		}
 
 		try {
-			// Update stage for frontend polling.
 			$this->update_generation_stage( __( 'Collecting sources from Reddit...', 'prautoblogger' ) );
 
 			$results = ( new PRAutoBlogger_Pipeline_Runner() )
@@ -188,7 +185,7 @@ class PRAutoBlogger_Executor {
 				'message' => $e->getMessage(),
 			], self::STATUS_TTL );
 		} finally {
-			$this->release_generation_lock();
+			PRAutoBlogger_Generation_Lock::release();
 		}
 	}
 
@@ -198,7 +195,12 @@ class PRAutoBlogger_Executor {
 	 * Lightweight endpoint — reads a transient and returns it. Called every
 	 * few seconds by admin.js while generation is in progress.
 	 *
-	 * Side effects: none.
+	 * Includes fallback detection: if the pipeline produced a post but the
+	 * PHP process was killed before updating the transient (Hostinger's
+	 * 120-second timeout), this endpoint detects the orphaned state and
+	 * recovers gracefully after 180 seconds.
+	 *
+	 * Side effects: may delete stale transient and lock on recovery.
 	 */
 	public function on_ajax_generation_status(): void {
 		check_ajax_referer( 'prautoblogger_generate_now', 'nonce' );
@@ -215,10 +217,7 @@ class PRAutoBlogger_Executor {
 			return;
 		}
 
-		// If still "running" but the generation lock is released, the pipeline
-		// finished but the transient update was lost (e.g., PHP process killed
-		// by Hostinger after LiteSpeed connection timeout). Detect this by
-		// checking if the lock is gone and a recent post exists.
+		// Fallback: detect orphaned "running" state when PHP process was killed.
 		if ( 'running' === $status['status'] ) {
 			$started = $status['started'] ?? 0;
 			$elapsed = time() - $started;
@@ -233,10 +232,8 @@ class PRAutoBlogger_Executor {
 				return;
 			}
 
-			// After 2 minutes, check if the lock was released (pipeline finished
-			// but transient never updated). Look for a post created since the run
-			// started to confirm success.
-			if ( $elapsed > 120 && ! $this->is_generation_locked() ) {
+			// After 3 minutes, check if pipeline produced output despite the kill.
+			if ( $elapsed > 180 ) {
 				$recent = get_posts( [
 					'post_type'      => 'post',
 					'post_status'    => [ 'publish', 'draft' ],
@@ -247,6 +244,8 @@ class PRAutoBlogger_Executor {
 					'order'          => 'DESC',
 				] );
 				delete_transient( self::STATUS_TRANSIENT );
+				PRAutoBlogger_Generation_Lock::release();
+
 				if ( ! empty( $recent ) ) {
 					wp_send_json_success( [
 						'status'    => 'complete',
@@ -282,120 +281,6 @@ class PRAutoBlogger_Executor {
 		}
 	}
 
-	/**
-	 * AJAX handler: generate images for existing posts that lack them.
-	 *
-	 * Accepts a `post_id` parameter. Generates Image A (article-driven) and
-	 * sets it as the featured image. Useful for retroactively adding images
-	 * to posts published before image generation was enabled/fixed.
-	 *
-	 * Side effects: Cloudflare API call, media library write, post meta update.
-	 */
-	public function on_ajax_generate_image(): void {
-		check_ajax_referer( 'prautoblogger_generate_image', 'nonce' );
-
-		if ( ! current_user_can( 'manage_options' ) ) {
-			wp_send_json_error( [ 'message' => __( 'Insufficient permissions.', 'prautoblogger' ) ], 403 );
-			return;
-		}
-
-		// Image generation can take 20-30s on Cloudflare Workers AI.
-		// phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged
-		@set_time_limit( 120 );
-
-		$post_id = isset( $_POST['post_id'] ) ? absint( $_POST['post_id'] ) : 0;
-		if ( 0 === $post_id ) {
-			wp_send_json_error( [ 'message' => __( 'Missing post_id parameter.', 'prautoblogger' ) ] );
-			return;
-		}
-
-		$post = get_post( $post_id );
-		if ( ! $post ) {
-			wp_send_json_error( [ 'message' => sprintf( __( 'Post %d not found.', 'prautoblogger' ), $post_id ) ] );
-			return;
-		}
-
-		try {
-			$pipeline     = new PRAutoBlogger_Image_Pipeline();
-			$article_data = [
-				'post_title'   => $post->post_title,
-				'post_content' => $post->post_content,
-			];
-
-			// Retrieve original source IDs from post meta so Image B can generate
-			// a source-driven prompt even on retroactive regeneration.
-			$source_ids_json = get_post_meta( $post_id, '_prautoblogger_source_ids', true );
-			$source_ids      = is_string( $source_ids_json ) ? json_decode( $source_ids_json, true ) : [];
-			$source_data     = ( new PRAutoBlogger_Source_Collector() )->get_source_data_for_image(
-				is_array( $source_ids ) ? array_map( 'absint', $source_ids ) : []
-			);
-
-			// The pipeline now sets featured image and Image B meta
-			// internally, immediately after each image generates.
-			$result = $pipeline->generate_and_attach_images( $post_id, $article_data, $source_data );
-
-			wp_send_json_success( $result );
-		} catch ( \Throwable $e ) {
-			PRAutoBlogger_Logger::instance()->error(
-				sprintf( 'Retroactive image gen %s for post %d: %s', get_class( $e ), $post_id, $e->getMessage() ),
-				'image_pipeline'
-			);
-			wp_send_json_error( [ 'message' => $e->getMessage() ] );
-		}
-	}
-
-	/**
-	 * AJAX handler: return the model registry for the admin model picker.
-	 *
-	 * Returns the full cached model list. If the registry is empty, triggers
-	 * a refresh first. Called by the model-picker.js popup.
-	 *
-	 * Side effects: may trigger an OpenRouter API call if registry is empty.
-	 */
-	public function on_ajax_get_models(): void {
-		check_ajax_referer( 'prautoblogger_get_models', 'nonce' );
-
-		if ( ! current_user_can( 'manage_options' ) ) {
-			wp_send_json_error( [ 'message' => __( 'Insufficient permissions.', 'prautoblogger' ) ], 403 );
-			return;
-		}
-
-		$registry = $this->get_model_registry();
-		$models   = $registry->get_models();
-
-		// Auto-refresh if the registry has never been populated.
-		if ( empty( $models ) ) {
-			$registry->refresh( true );
-			$models = $registry->get_models();
-		}
-
-		wp_send_json_success( $models );
-	}
-
-	/** AJAX handler: test API connections (OpenRouter, Reddit). */
-	public function on_ajax_test_connection(): void {
-		check_ajax_referer( 'prautoblogger_test_connection', 'nonce' );
-		if ( ! current_user_can( 'manage_options' ) ) {
-			wp_send_json_error( [ 'message' => __( 'Insufficient permissions.', 'prautoblogger' ) ], 403 );
-			return;
-		}
-
-		$service = isset( $_POST['service'] ) ? sanitize_text_field( wp_unslash( $_POST['service'] ) ) : '';
-		$results = [];
-
-		if ( 'openrouter' === $service || 'all' === $service ) {
-			$results['openrouter'] = ( new PRAutoBlogger_OpenRouter_Provider() )->validate_credentials_detailed();
-		}
-		if ( 'reddit' === $service || 'all' === $service ) {
-			$reddit  = new PRAutoBlogger_Reddit_Provider();
-			$is_ok   = $reddit->validate_credentials();
-			$results['reddit'] = $is_ok
-				? [ 'status' => 'ok', 'message' => __( 'Reddit source available (RSS primary, .json fallback).', 'prautoblogger' ) ]
-				: [ 'status' => 'error', 'message' => __( 'Reddit sources unreachable (both RSS and .json failed).', 'prautoblogger' ) ];
-		}
-		wp_send_json_success( $results );
-	}
-
 	/**
 	 * Lazy-load the OpenRouter model registry singleton.
 	 * Config injected here — registry class has no knowledge of PRAUTOBLOGGER_* constants.
@@ -411,72 +296,4 @@ class PRAutoBlogger_Executor {
 		}
 		return $this->model_registry;
 	}
-
-	/**
-	 * Acquire a database-level atomic mutex for generation.
-	 * Uses INSERT IGNORE — option_name UNIQUE index guarantees single-writer.
-	 * Expired locks (>1 hour) are cleaned up first.
-	 *
-	 * @return bool True if lock acquired.
-	 */
-	public function acquire_generation_lock(): bool {
-		global $wpdb;
-
-		$lock_name = 'prautoblogger_generation_lock';
-
-		// Clean up expired locks to prevent permanent deadlock.
-		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching
-		$wpdb->query(
-			$wpdb->prepare(
-				"DELETE FROM {$wpdb->options} WHERE option_name = %s AND CAST(option_value AS UNSIGNED) < %d",
-				$lock_name,
-				time() - HOUR_IN_SECONDS
-			)
-		);
-
-		// Atomic insert — UNIQUE constraint guarantees only one process succeeds.
-		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery
-		$result = $wpdb->query(
-			$wpdb->prepare(
-				"INSERT IGNORE INTO {$wpdb->options} (option_name, option_value, autoload) VALUES (%s, %s, %s)",
-				$lock_name,
-				(string) time(),
-				'no'
-			)
-		);
-
-		return $result > 0;
-	}
-
-	/**
-	 * Check if the generation lock is currently held.
-	 *
-	 * @return bool True if the lock exists (generation in progress or stuck).
-	 */
-	public function is_generation_locked(): bool {
-		global $wpdb;
-
-		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching
-		$row = $wpdb->get_var(
-			$wpdb->prepare(
-				"SELECT option_value FROM {$wpdb->options} WHERE option_name = %s LIMIT 1",
-				'prautoblogger_generation_lock'
-			)
-		);
-
-		return null !== $row;
-	}
-
-	/** Release the generation mutex. */
-	public function release_generation_lock(): void {
-		global $wpdb;
-
-		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching
-		$wpdb->query(
-			$wpdb->prepare(
-				"DELETE FROM {$wpdb->options} WHERE option_name = %s",
-				'prautoblogger_generation_lock'
-			)
-		);
-	}
 }
diff --git a/includes/class-generation-lock.php b/includes/class-generation-lock.php
new file mode 100644
index 0000000..d1e5b35
--- /dev/null
+++ b/includes/class-generation-lock.php
@@ -0,0 +1,95 @@
+<?php
+declare(strict_types=1);
+
+/**
+ * Database-level atomic mutex for content generation.
+ *
+ * What: Provides acquire/release/check semantics for a single-writer generation lock.
+ * Who calls it: PRAutoBlogger_Executor (daily and manual generation), status polling fallback.
+ * Dependencies: WordPress $wpdb for direct SQL.
+ *
+ * Uses INSERT IGNORE against the wp_options UNIQUE index on option_name to
+ * guarantee only one PHP process can hold the lock at a time. Expired locks
+ * (>1 hour) are cleaned up automatically on acquire to prevent permanent deadlock.
+ *
+ * @see class-executor.php — Acquires/releases the lock around pipeline runs.
+ * @see class-ajax-handlers.php — Releases stale locks in the status fallback path.
+ */
+class PRAutoBlogger_Generation_Lock {
+
+	/** @var string Option name used as the lock key in wp_options. */
+	private const LOCK_NAME = 'prautoblogger_generation_lock';
+
+	/**
+	 * Acquire the generation mutex.
+	 *
+	 * Cleans up expired locks (>1 hour) first, then attempts an atomic INSERT
+	 * IGNORE. The UNIQUE constraint on option_name ensures only one caller wins.
+	 *
+	 * @return bool True if lock acquired, false if already held.
+	 */
+	public static function acquire(): bool {
+		global $wpdb;
+
+		// Clean up expired locks to prevent permanent deadlock.
+		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching
+		$wpdb->query(
+			$wpdb->prepare(
+				"DELETE FROM {$wpdb->options} WHERE option_name = %s AND CAST(option_value AS UNSIGNED) < %d",
+				self::LOCK_NAME,
+				time() - HOUR_IN_SECONDS
+			)
+		);
+
+		// Atomic insert — UNIQUE constraint guarantees only one process succeeds.
+		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery
+		$result = $wpdb->query(
+			$wpdb->prepare(
+				"INSERT IGNORE INTO {$wpdb->options} (option_name, option_value, autoload) VALUES (%s, %s, %s)",
+				self::LOCK_NAME,
+				(string) time(),
+				'no'
+			)
+		);
+
+		return $result > 0;
+	}
+
+	/**
+	 * Check if the generation lock is currently held.
+	 *
+	 * @return bool True if the lock exists (generation in progress or stuck).
+	 */
+	public static function is_locked(): bool {
+		global $wpdb;
+
+		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching
+		$row = $wpdb->get_var(
+			$wpdb->prepare(
+				"SELECT option_value FROM {$wpdb->options} WHERE option_name = %s LIMIT 1",
+				self::LOCK_NAME
+			)
+		);
+
+		return null !== $row;
+	}
+
+	/**
+	 * Release the generation mutex.
+	 *
+	 * Safe to call even if the lock is not held (no-ops gracefully).
+	 *
+	 * Side effects: deletes the lock row from wp_options.
+	 */
+	public static function release(): void {
+		global $wpdb;
+
+		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching
+		$wpdb->query(
+			$wpdb->prepare(
+				"DELETE FROM {$wpdb->options} WHERE option_name = %s",
+				self::LOCK_NAME
+			)
+		);
+	}
+}
diff --git a/includes/class-prautoblogger.php b/includes/class-prautoblogger.php
index 015e4cc..0b8f33e 100644
--- a/includes/class-prautoblogger.php
+++ b/includes/class-prautoblogger.php
@@ -12,7 +12,9 @@ declare(strict_types=1);
  * Dependencies: All other plugin classes (loaded via autoloader), PRAutoBlogger_Executor.
  *
  * @see prautoblogger.php                     — Plugin bootstrap that instantiates this class.
- * @see class-prautoblogger-executor.php       — Cron/AJAX handlers, generation lock, model registry.
+ * @see class-executor.php                    — Cron/AJAX handlers for generation, model registry.
+ * @see class-ajax-handlers.php               — Non-generation AJAX endpoints (images, models, test).
+ * @see class-generation-lock.php             — DB mutex for single-writer generation.
  * @see core/class-pipeline-runner.php         — Executes the generation pipeline.
  * @see ARCHITECTURE.md                        — Data flow diagram showing how classes interact.
  * @see CONVENTIONS.md                         — Hook naming conventions.
@@ -21,9 +23,12 @@ class PRAutoBlogger {
 
 	private bool $initialized = false;
 
-	/** @var PRAutoBlogger_Executor Handles execution: cron, AJAX, locking, model registry. */
+	/** @var PRAutoBlogger_Executor Handles generation cron/AJAX, model registry. */
 	private PRAutoBlogger_Executor $executor;
 
+	/** @var PRAutoBlogger_Ajax_Handlers Handles non-generation AJAX (images, models, test). */
+	private PRAutoBlogger_Ajax_Handlers $ajax_handlers;
+
 	/**
 	 * Register all hooks and initialize the plugin.
 	 * Called once on `plugins_loaded`. Idempotent.
@@ -34,8 +39,9 @@ class PRAutoBlogger {
 		if ( $this->initialized ) {
 			return;
 		}
-		$this->initialized = true;
-		$this->executor    = new PRAutoBlogger_Executor();
+		$this->initialized  = true;
+		$this->executor     = new PRAutoBlogger_Executor();
+		$this->ajax_handlers = new PRAutoBlogger_Ajax_Handlers( $this->executor->get_model_registry() );
 
 		add_action( 'admin_init', [ $this, 'on_check_db_version' ] );
 		add_filter( 'cron_schedules', [ $this, 'filter_add_cron_schedules' ] );
@@ -95,11 +101,14 @@ class PRAutoBlogger {
 
 	/** Register AJAX handlers for admin actions. */
 	private function register_ajax_hooks(): void {
+		// Generation AJAX (start + status polling) stays on executor.
 		add_action( 'wp_ajax_prautoblogger_generate_now', [ $this->executor, 'on_ajax_generate_now' ] );
 		add_action( 'wp_ajax_prautoblogger_generation_status', [ $this->executor, 'on_ajax_generation_status' ] );
-		add_action( 'wp_ajax_prautoblogger_generate_image', [ $this->executor, 'on_ajax_generate_image' ] );
-		add_action( 'wp_ajax_prautoblogger_test_connection', [ $this->executor, 'on_ajax_test_connection' ] );
-		add_action( 'wp_ajax_prautoblogger_get_models', [ $this->executor, 'on_ajax_get_models' ] );
+
+		// Non-generation AJAX (images, models, test) on dedicated handler.
+		add_action( 'wp_ajax_prautoblogger_generate_image', [ $this->ajax_handlers, 'on_ajax_generate_image' ] );
+		add_action( 'wp_ajax_prautoblogger_test_connection', [ $this->ajax_handlers, 'on_ajax_test_connection' ] );
+		add_action( 'wp_ajax_prautoblogger_get_models', [ $this->ajax_handlers, 'on_ajax_get_models' ] );
 
 		$review_queue = new PRAutoBlogger_Review_Queue();
 		add_action( 'wp_ajax_prautoblogger_approve_post', [ $review_queue, 'on_ajax_approve_post' ] );
@@ -196,7 +205,7 @@ class PRAutoBlogger {
 		return $this->executor;
 	}
 
-	// ── Backward-compatible proxies (execution moved to PRAutoBlogger_Executor) ──
+	// ── Backward-compatible proxies ──
 
 	/** @see PRAutoBlogger_Executor::on_daily_generation() */
 	public function on_daily_generation(): void { $this->executor->on_daily_generation(); }
@@ -207,8 +216,8 @@ class PRAutoBlogger {
 	/** @see PRAutoBlogger_Executor::on_ajax_generate_now() */
 	public function on_ajax_generate_now(): void { $this->executor->on_ajax_generate_now(); }
 
-	/** @see PRAutoBlogger_Executor::on_ajax_test_connection() */
-	public function on_ajax_test_connection(): void { $this->executor->on_ajax_test_connection(); }
+	/** @see PRAutoBlogger_Ajax_Handlers::on_ajax_test_connection() */
+	public function on_ajax_test_connection(): void { $this->ajax_handlers->on_ajax_test_connection(); }
 
 	/** @see PRAutoBlogger_Executor::get_model_registry() */
 	public function get_model_registry(): PRAutoBlogger_OpenRouter_Model_Registry { return $this->executor->get_model_registry(); }