diff --git a/VERSION b/VERSION
index c5106e6..7636e75 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-4.0.4
+4.0.5
diff --git a/play-life-backend/migrations/000003_add_reward_configs_covering_index.down.sql b/play-life-backend/migrations/000003_add_reward_configs_covering_index.down.sql
new file mode 100644
index 0000000..291e61b
--- /dev/null
+++ b/play-life-backend/migrations/000003_add_reward_configs_covering_index.down.sql
@@ -0,0 +1,3 @@
+-- Rollback migration: Remove covering index for reward_configs
+
+DROP INDEX IF EXISTS idx_reward_configs_task_id_covering;
diff --git a/play-life-backend/migrations/000003_add_reward_configs_covering_index.up.sql b/play-life-backend/migrations/000003_add_reward_configs_covering_index.up.sql
new file mode 100644
index 0000000..a22f5dc
--- /dev/null
+++ b/play-life-backend/migrations/000003_add_reward_configs_covering_index.up.sql
@@ -0,0 +1,14 @@
+-- Migration: Add covering index for reward_configs to optimize subtask rewards queries
+-- Date: 2026-01-26
+--
+-- This migration adds a covering index to optimize queries that load rewards for multiple subtasks.
+-- The index includes all columns needed for the query, allowing PostgreSQL to perform
+-- index-only scans without accessing the main table.
+--
+-- Covering index for reward_configs query
+-- Includes all columns needed for rewards selection to avoid table lookups
+CREATE INDEX IF NOT EXISTS idx_reward_configs_task_id_covering 
+ON reward_configs(task_id, position) 
+INCLUDE (id, project_id, value, use_progression);
+
+COMMENT ON INDEX idx_reward_configs_task_id_covering IS 'Covering index for rewards query - includes all selected columns to avoid table lookups. Enables index-only scans for better performance when loading rewards for multiple tasks.';
diff --git a/play-life-web/package.json b/play-life-web/package.json
index 2409ec6..861be35 100644
--- a/play-life-web/package.json
+++ b/play-life-web/package.json
@@ -1,6 +1,6 @@
 {
   "name": "play-life-web",
-  "version": "4.0.4",
+  "version": "4.0.5",
   "type": "module",
   "scripts": {
     "dev": "vite",