diff --git a/esphome/components/improv_serial/__init__.py b/esphome/components/improv_serial/__init__.py
index 9a2ac2f40f..4266f5b78b 100644
--- a/esphome/components/improv_serial/__init__.py
+++ b/esphome/components/improv_serial/__init__.py
@@ -43,3 +43,4 @@ async def to_code(config):
     var = cg.new_Pvariable(config[CONF_ID])
     await cg.register_component(var, config)
     await improv_base.setup_improv_core(var, config, "improv_serial")
+    cg.add_define("USE_IMPROV_SERIAL")
diff --git a/esphome/components/wifi/wifi_component.cpp b/esphome/components/wifi/wifi_component.cpp
index 1e6961b8bd..7d5d0133c1 100644
--- a/esphome/components/wifi/wifi_component.cpp
+++ b/esphome/components/wifi/wifi_component.cpp
@@ -2121,7 +2121,7 @@ bool WiFiComponent::can_proceed() {
 #endif
 
 void WiFiComponent::set_reboot_timeout(uint32_t reboot_timeout) { this->reboot_timeout_ = reboot_timeout; }
-bool WiFiComponent::is_connected() {
+bool WiFiComponent::is_connected() const {
   return this->state_ == WIFI_COMPONENT_STATE_STA_CONNECTED &&
          this->wifi_sta_connect_status_() == WiFiSTAConnectStatus::CONNECTED && !this->error_from_callback_;
 }
diff --git a/esphome/components/wifi/wifi_component.h b/esphome/components/wifi/wifi_component.h
index 63c7039f21..a6f03a08d9 100644
--- a/esphome/components/wifi/wifi_component.h
+++ b/esphome/components/wifi/wifi_component.h
@@ -443,7 +443,7 @@ class WiFiComponent : public Component {
 
   void set_reboot_timeout(uint32_t reboot_timeout);
 
-  bool is_connected();
+  bool is_connected() const;
 
   void set_power_save_mode(WiFiPowerSaveMode power_save);
   void set_min_auth_mode(WifiMinAuthMode min_auth_mode) { min_auth_mode_ = min_auth_mode; }
@@ -677,7 +677,7 @@ class WiFiComponent : public Component {
   bool wifi_apply_hostname_();
   bool wifi_sta_connect_(const WiFiAP &ap);
   void wifi_pre_setup_();
-  WiFiSTAConnectStatus wifi_sta_connect_status_();
+  WiFiSTAConnectStatus wifi_sta_connect_status_() const;
   bool wifi_scan_start_(bool passive);
 
 #ifdef USE_WIFI_AP
diff --git a/esphome/components/wifi/wifi_component_esp8266.cpp b/esphome/components/wifi/wifi_component_esp8266.cpp
index 8911bf15e0..bd6a18a99b 100644
--- a/esphome/components/wifi/wifi_component_esp8266.cpp
+++ b/esphome/components/wifi/wifi_component_esp8266.cpp
@@ -622,7 +622,7 @@ void WiFiComponent::wifi_pre_setup_() {
   this->wifi_mode_(false, false);
 }
 
-WiFiSTAConnectStatus WiFiComponent::wifi_sta_connect_status_() {
+WiFiSTAConnectStatus WiFiComponent::wifi_sta_connect_status_() const {
   station_status_t status = wifi_station_get_connect_status();
   if (status == STATION_GOT_IP)
     return WiFiSTAConnectStatus::CONNECTED;
diff --git a/esphome/components/wifi/wifi_component_esp_idf.cpp b/esphome/components/wifi/wifi_component_esp_idf.cpp
index 57bbceb1b8..734d186205 100644
--- a/esphome/components/wifi/wifi_component_esp_idf.cpp
+++ b/esphome/components/wifi/wifi_component_esp_idf.cpp
@@ -921,7 +921,7 @@ void WiFiComponent::wifi_process_event_(IDFWiFiEvent *data) {
   }
 }
 
-WiFiSTAConnectStatus WiFiComponent::wifi_sta_connect_status_() {
+WiFiSTAConnectStatus WiFiComponent::wifi_sta_connect_status_() const {
   if (s_sta_connected && this->got_ipv4_address_) {
 #if USE_NETWORK_IPV6 && (USE_NETWORK_MIN_IPV6_ADDR_COUNT > 0)
     if (this->num_ipv6_addresses_ >= USE_NETWORK_MIN_IPV6_ADDR_COUNT) {
diff --git a/esphome/components/wifi/wifi_component_libretiny.cpp b/esphome/components/wifi/wifi_component_libretiny.cpp
index 1c5490a3ac..4c4150e44d 100644
--- a/esphome/components/wifi/wifi_component_libretiny.cpp
+++ b/esphome/components/wifi/wifi_component_libretiny.cpp
@@ -634,7 +634,7 @@ void WiFiComponent::wifi_pre_setup_() {
   // Make sure WiFi is in clean state before anything starts
   this->wifi_mode_(false, false);
 }
-WiFiSTAConnectStatus WiFiComponent::wifi_sta_connect_status_() {
+WiFiSTAConnectStatus WiFiComponent::wifi_sta_connect_status_() const {
   // Use state machine instead of querying WiFi.status() directly
   // State is updated in main loop from queued events, ensuring thread safety
   switch (s_sta_state) {
diff --git a/esphome/components/wifi/wifi_component_pico_w.cpp b/esphome/components/wifi/wifi_component_pico_w.cpp
index 9b2c077dc5..270425d8c2 100644
--- a/esphome/components/wifi/wifi_component_pico_w.cpp
+++ b/esphome/components/wifi/wifi_component_pico_w.cpp
@@ -120,7 +120,7 @@ const char *get_disconnect_reason_str(uint8_t reason) {
   return "UNKNOWN";
 }
 
-WiFiSTAConnectStatus WiFiComponent::wifi_sta_connect_status_() {
+WiFiSTAConnectStatus WiFiComponent::wifi_sta_connect_status_() const {
   // Use cyw43_wifi_link_status instead of cyw43_tcpip_link_status because the Arduino
   // framework's __wrap_cyw43_cb_tcpip_init is a no-op — the SDK's internal netif
   // (cyw43_state.netif[]) is never initialized. cyw43_tcpip_link_status checks that netif's
diff --git a/esphome/core/defines.h b/esphome/core/defines.h
index 5c982c94b1..181425c162 100644
--- a/esphome/core/defines.h
+++ b/esphome/core/defines.h
@@ -55,6 +55,7 @@
 #define USE_HOMEASSISTANT_TIME
 #define USE_HTTP_REQUEST_OTA_WATCHDOG_TIMEOUT 8000  // NOLINT
 #define USE_IMAGE
+#define USE_IMPROV_SERIAL
 #define USE_IMPROV_SERIAL_NEXT_URL
 #define USE_INFRARED
 #define USE_IR_RF