diff --git a/core/runner/Sandbox.go b/core/runner/Sandbox.go
index 0a1d10c..291ddbd 100644
--- a/core/runner/Sandbox.go
+++ b/core/runner/Sandbox.go
@@ -9,6 +9,8 @@ import (
 
 	"Moonshark/core/utils/logger"
 
+	"maps"
+
 	luajit "git.sharkk.net/Sky/LuaJIT-to-Go"
 )
 
@@ -141,12 +143,16 @@ func (s *Sandbox) Execute(state *luajit.State, bytecode []byte, ctx *Context) (*
 		}
 		state.SetGlobal("__session_data")
 
-		// Reset modification flag
+		// Reset modification flag and tracking
 		state.PushBoolean(false)
 		state.SetGlobal("__session_modified")
+
+		// Create empty modified keys table
+		state.NewTable()
+		state.SetGlobal("__session_modified_keys")
 	} else {
 		// Initialize empty session
-		if err := state.DoString("__session_data = {}; __session_modified = false"); err != nil {
+		if err := state.DoString("__session_data = {}; __session_modified = false; __session_modified_keys = {}"); err != nil {
 			s.debugLog("Failed to initialize empty session data: %v", err)
 		}
 	}
@@ -275,9 +281,7 @@ func (s *Sandbox) extractResponseData(state *luajit.State, response *Response) {
 		if state.IsTable(-1) {
 			sessionData, err := state.ToTable(-1)
 			if err == nil {
-				for k, v := range sessionData {
-					response.SessionData[k] = v
-				}
+				maps.Copy(response.SessionData, sessionData)
 			}
 		}
 		state.Pop(1)
diff --git a/core/runner/sandbox.lua b/core/runner/sandbox.lua
index 324ea21..4f2c1f7 100644
--- a/core/runner/sandbox.lua
+++ b/core/runner/sandbox.lua
@@ -14,6 +14,7 @@ __ready_modules = {}
 __session_data = {}
 __session_id = nil
 __session_modified = false
+__session_modified_keys = {}
 
 -- ======================================================================
 -- CORE SANDBOX FUNCTIONALITY
@@ -299,12 +300,7 @@ local session = {
         if type(key) ~= "string" then
             error("session.get: key must be a string", 2)
         end
-
-        if __session_data and __session_data[key] ~= nil then
-            return __session_data[key]
-        end
-
-        return nil
+        return __session_data and __session_data[key]
     end,
 
     -- Set a session value
@@ -312,16 +308,9 @@ local session = {
         if type(key) ~= "string" then
             error("session.set: key must be a string", 2)
         end
-
-        -- Ensure session data table exists
         __session_data = __session_data or {}
-
-        -- Store value
         __session_data[key] = value
-
-        -- Mark session as modified
         __session_modified = true
-
         return true
     end,
 
@@ -331,9 +320,10 @@ local session = {
             error("session.delete: key must be a string", 2)
         end
 
-        if __session_data then
+        if __session_data and __session_data[key] ~= nil then
             __session_data[key] = nil
             __session_modified = true
+            __session_modified_keys[key] = true
         end
 
         return true
@@ -341,8 +331,15 @@ local session = {
 
     -- Clear all session data
     clear = function()
-        __session_data = {}
-        __session_modified = true
+        if __session_data and next(__session_data) then
+            -- Track all keys as modified
+            for k in pairs(__session_data) do
+                __session_modified_keys[k] = true
+            end
+            
+            __session_data = {}
+            __session_modified = true
+        end
         return true
     end,