diff --git a/esphome/components/alarm_control_panel/__init__.py b/esphome/components/alarm_control_panel/__init__.py
index ff1c0d1c302..4ee073a15b1 100644
--- a/esphome/components/alarm_control_panel/__init__.py
+++ b/esphome/components/alarm_control_panel/__init__.py
@@ -35,6 +35,7 @@ AlarmControlPanel = alarm_control_panel_ns.class_("AlarmControlPanel", cg.Entity
 
 StateAnyForwarder = alarm_control_panel_ns.class_("StateAnyForwarder")
 StateEnterForwarder = alarm_control_panel_ns.class_("StateEnterForwarder")
+AlarmControlPanelState = alarm_control_panel_ns.enum("AlarmControlPanelState")
 
 ArmAwayAction = alarm_control_panel_ns.class_("ArmAwayAction", automation.Action)
 ArmHomeAction = alarm_control_panel_ns.class_("ArmHomeAction", automation.Action)
@@ -117,13 +118,13 @@ async def setup_alarm_control_panel_core_(var, config):
             var, "add_on_state_callback", [], conf, forwarder=StateAnyForwarder
         )
     _STATE_ENTER_MAP = {
-        CONF_ON_TRIGGERED: "ACP_STATE_TRIGGERED",
-        CONF_ON_ARMING: "ACP_STATE_ARMING",
-        CONF_ON_PENDING: "ACP_STATE_PENDING",
-        CONF_ON_ARMED_HOME: "ACP_STATE_ARMED_HOME",
-        CONF_ON_ARMED_NIGHT: "ACP_STATE_ARMED_NIGHT",
-        CONF_ON_ARMED_AWAY: "ACP_STATE_ARMED_AWAY",
-        CONF_ON_DISARMED: "ACP_STATE_DISARMED",
+        CONF_ON_TRIGGERED: AlarmControlPanelState.ACP_STATE_TRIGGERED,
+        CONF_ON_ARMING: AlarmControlPanelState.ACP_STATE_ARMING,
+        CONF_ON_PENDING: AlarmControlPanelState.ACP_STATE_PENDING,
+        CONF_ON_ARMED_HOME: AlarmControlPanelState.ACP_STATE_ARMED_HOME,
+        CONF_ON_ARMED_NIGHT: AlarmControlPanelState.ACP_STATE_ARMED_NIGHT,
+        CONF_ON_ARMED_AWAY: AlarmControlPanelState.ACP_STATE_ARMED_AWAY,
+        CONF_ON_DISARMED: AlarmControlPanelState.ACP_STATE_DISARMED,
     }
     for conf_key, state_enum in _STATE_ENTER_MAP.items():
         for conf in config.get(conf_key, []):
@@ -132,7 +133,7 @@ async def setup_alarm_control_panel_core_(var, config):
                 "add_on_state_callback",
                 [],
                 conf,
-                forwarder=StateEnterForwarder.template(cg.RawExpression(state_enum)),
+                forwarder=StateEnterForwarder.template(state_enum),
             )
     for conf in config.get(CONF_ON_CLEARED, []):
         await automation.build_callback_automation(
diff --git a/esphome/components/alarm_control_panel/alarm_control_panel.cpp b/esphome/components/alarm_control_panel/alarm_control_panel.cpp
index 26921be13d3..fc72c13ce30 100644
--- a/esphome/components/alarm_control_panel/alarm_control_panel.cpp
+++ b/esphome/components/alarm_control_panel/alarm_control_panel.cpp
@@ -35,7 +35,7 @@ void AlarmControlPanel::publish_state(AlarmControlPanelState state) {
              LOG_STR_ARG(alarm_control_panel_state_to_string(state)),
              LOG_STR_ARG(alarm_control_panel_state_to_string(prev_state)));
     this->current_state_ = state;
-    // Single state callback - triggers check get_state() for specific states
+    // Single state callback - listeners receive the new state as an argument
     this->state_callback_.call(state);
 #if defined(USE_ALARM_CONTROL_PANEL) && defined(USE_CONTROLLER_REGISTRY)
     ControllerRegistry::notify_alarm_control_panel_update(this);
diff --git a/esphome/components/nextion/nextion.cpp b/esphome/components/nextion/nextion.cpp
index 612bfbc968c..fa1582c209f 100644
--- a/esphome/components/nextion/nextion.cpp
+++ b/esphome/components/nextion/nextion.cpp
@@ -10,6 +10,10 @@ namespace nextion {
 
 static const char *const TAG = "nextion";
 
+// Nextion command terminator: three consecutive 0xFF bytes (per Nextion Instruction Set v1.1).
+static constexpr uint8_t COMMAND_DELIMITER[3] = {0xFF, 0xFF, 0xFF};
+static constexpr size_t DELIMITER_SIZE = sizeof(COMMAND_DELIMITER);
+
 void Nextion::setup() {
   this->is_setup_ = false;
   this->connection_state_.ignore_is_setup_ = true;
@@ -415,7 +419,8 @@ void Nextion::process_nextion_commands_() {
 #ifdef NEXTION_PROTOCOL_LOG
   this->print_queue_members_();
 #endif
-  while ((to_process_length = this->command_data_.find(COMMAND_DELIMITER)) != std::string::npos) {
+  while ((to_process_length = this->command_data_.find(reinterpret_cast<const char *>(COMMAND_DELIMITER), 0,
+                                                       DELIMITER_SIZE)) != std::string::npos) {
 #ifdef USE_NEXTION_MAX_COMMANDS_PER_LOOP
     if (++commands_processed > this->max_commands_per_loop_) {
       ESP_LOGW(TAG, "Command processing limit exceeded");
@@ -423,8 +428,8 @@ void Nextion::process_nextion_commands_() {
     }
 #endif  // USE_NEXTION_MAX_COMMANDS_PER_LOOP
     ESP_LOGN(TAG, "queue size: %zu", this->nextion_queue_.size());
-    while (to_process_length + COMMAND_DELIMITER.length() < this->command_data_.length() &&
-           static_cast<uint8_t>(this->command_data_[to_process_length + COMMAND_DELIMITER.length()]) == 0xFF) {
+    while (to_process_length + DELIMITER_SIZE < this->command_data_.length() &&
+           static_cast<uint8_t>(this->command_data_[to_process_length + DELIMITER_SIZE]) == 0xFF) {
       ++to_process_length;
       ESP_LOGN(TAG, "Add 0xFF");
     }
@@ -829,7 +834,7 @@ void Nextion::process_nextion_commands_() {
         break;
     }
 
-    this->command_data_.erase(0, to_process_length + COMMAND_DELIMITER.length() + 1);
+    this->command_data_.erase(0, to_process_length + DELIMITER_SIZE + 1);
   }
 
   const uint32_t ms = App.get_loop_component_start_time();
diff --git a/esphome/components/nextion/nextion.h b/esphome/components/nextion/nextion.h
index bb5998cf5dd..217d2e605d2 100644
--- a/esphome/components/nextion/nextion.h
+++ b/esphome/components/nextion/nextion.h
@@ -29,8 +29,6 @@ class NextionComponentBase;
 
 using nextion_writer_t = display::DisplayWriter<Nextion>;
 
-static const std::string COMMAND_DELIMITER{static_cast<char>(255), static_cast<char>(255), static_cast<char>(255)};
-
 #ifdef USE_NEXTION_COMMAND_SPACING
 class NextionCommandPacer {
  public: