From 36ab68c1ea3260e1f2fe693f5287826b26d8a8ab Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Fri, 10 Oct 2025 17:31:13 -1000
Subject: [PATCH 01/90] [esp32_ble] Partial revert of #10862 - Fix GATT client
 notifications

---
 esphome/components/esp32_ble/__init__.py | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/esphome/components/esp32_ble/__init__.py b/esphome/components/esp32_ble/__init__.py
index 15afb22ab8..caa3934707 100644
--- a/esphome/components/esp32_ble/__init__.py
+++ b/esphome/components/esp32_ble/__init__.py
@@ -332,12 +332,15 @@ def final_validation(config):
 
     # Check if BLE Server is needed
     has_ble_server = "esp32_ble_server" in full_config
-    add_idf_sdkconfig_option("CONFIG_BT_GATTS_ENABLE", has_ble_server)
 
     # Check if BLE Client is needed (via esp32_ble_tracker or esp32_ble_client)
     has_ble_client = (
         "esp32_ble_tracker" in full_config or "esp32_ble_client" in full_config
     )
+
+    # ESP-IDF BLE stack requires GATT Server to be enabled when GATT Client is enabled
+    # This is an internal dependency in the Bluedroid stack (tested up to ESP-IDF 5.5.1)
+    add_idf_sdkconfig_option("CONFIG_BT_GATTS_ENABLE", has_ble_server or has_ble_client)
     add_idf_sdkconfig_option("CONFIG_BT_GATTC_ENABLE", has_ble_client)
 
     # Handle max_connections: check for deprecated location in esp32_ble_tracker

From 3ea929eeb2893668807bbbd9f0bf4ba9f21aa218 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Fri, 10 Oct 2025 17:37:36 -1000
Subject: [PATCH 02/90] adj

---
 esphome/components/esp32_ble/__init__.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/esphome/components/esp32_ble/__init__.py b/esphome/components/esp32_ble/__init__.py
index caa3934707..816967135d 100644
--- a/esphome/components/esp32_ble/__init__.py
+++ b/esphome/components/esp32_ble/__init__.py
@@ -339,7 +339,7 @@ def final_validation(config):
     )
 
     # ESP-IDF BLE stack requires GATT Server to be enabled when GATT Client is enabled
-    # This is an internal dependency in the Bluedroid stack (tested up to ESP-IDF 5.5.1)
+    # This is an internal dependency in the Bluedroid stack (tested ESP-IDF 5.4.2-5.5.1)
     add_idf_sdkconfig_option("CONFIG_BT_GATTS_ENABLE", has_ble_server or has_ble_client)
     add_idf_sdkconfig_option("CONFIG_BT_GATTC_ENABLE", has_ble_client)
 

From 632cd929ac2ca98b345a3f397328b575bdcf6b4c Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Fri, 10 Oct 2025 17:38:26 -1000
Subject: [PATCH 03/90] adj

---
 esphome/components/esp32_ble/__init__.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/esphome/components/esp32_ble/__init__.py b/esphome/components/esp32_ble/__init__.py
index 816967135d..05ef936baf 100644
--- a/esphome/components/esp32_ble/__init__.py
+++ b/esphome/components/esp32_ble/__init__.py
@@ -340,6 +340,7 @@ def final_validation(config):
 
     # ESP-IDF BLE stack requires GATT Server to be enabled when GATT Client is enabled
     # This is an internal dependency in the Bluedroid stack (tested ESP-IDF 5.4.2-5.5.1)
+    # See: https://github.com/espressif/esp-idf/issues/17724
     add_idf_sdkconfig_option("CONFIG_BT_GATTS_ENABLE", has_ble_server or has_ble_client)
     add_idf_sdkconfig_option("CONFIG_BT_GATTC_ENABLE", has_ble_client)
 

From 8a4bd0f21c4a93b49f3ee1295f4a0ddc2ea863ed Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Fri, 10 Oct 2025 19:42:41 -1000
Subject: [PATCH 04/90] [socket] Split LWIP socket classes to reduce memory
 overhead on ESP8266/RP2040

---
 .../components/socket/lwip_raw_tcp_impl.cpp   | 190 +++++++++++-------
 1 file changed, 113 insertions(+), 77 deletions(-)

diff --git a/esphome/components/socket/lwip_raw_tcp_impl.cpp b/esphome/components/socket/lwip_raw_tcp_impl.cpp
index 3377682474..2d23cbc5c6 100644
--- a/esphome/components/socket/lwip_raw_tcp_impl.cpp
+++ b/esphome/components/socket/lwip_raw_tcp_impl.cpp
@@ -40,33 +40,14 @@ class LWIPRawImpl : public Socket {
   void init() {
     LWIP_LOG("init(%p)", pcb_);
     tcp_arg(pcb_, this);
-    tcp_accept(pcb_, LWIPRawImpl::s_accept_fn);
     tcp_recv(pcb_, LWIPRawImpl::s_recv_fn);
     tcp_err(pcb_, LWIPRawImpl::s_err_fn);
   }
 
   std::unique_ptr<Socket> accept(struct sockaddr *addr, socklen_t *addrlen) override {
-    if (pcb_ == nullptr) {
-      errno = EBADF;
-      return nullptr;
-    }
-    if (this->accepted_socket_count_ == 0) {
-      errno = EWOULDBLOCK;
-      return nullptr;
-    }
-    // Take from front for FIFO ordering
-    std::unique_ptr<LWIPRawImpl> sock = std::move(this->accepted_sockets_[0]);
-    // Shift remaining sockets forward
-    for (uint8_t i = 1; i < this->accepted_socket_count_; i++) {
-      this->accepted_sockets_[i - 1] = std::move(this->accepted_sockets_[i]);
-    }
-    this->accepted_socket_count_--;
-    LWIP_LOG("Connection accepted by application, queue size: %d", this->accepted_socket_count_);
-    if (addr != nullptr) {
-      sock->getpeername(addr, addrlen);
-    }
-    LWIP_LOG("accept(%p)", sock.get());
-    return std::unique_ptr<Socket>(std::move(sock));
+    // Non-listening sockets return error
+    errno = EINVAL;
+    return nullptr;
   }
   int bind(const struct sockaddr *name, socklen_t addrlen) override {
     if (pcb_ == nullptr) {
@@ -292,25 +273,10 @@ class LWIPRawImpl : public Socket {
     return -1;
   }
   int listen(int backlog) override {
-    if (pcb_ == nullptr) {
-      errno = EBADF;
-      return -1;
-    }
-    LWIP_LOG("tcp_listen_with_backlog(%p backlog=%d)", pcb_, backlog);
-    struct tcp_pcb *listen_pcb = tcp_listen_with_backlog(pcb_, backlog);
-    if (listen_pcb == nullptr) {
-      tcp_abort(pcb_);
-      pcb_ = nullptr;
-      errno = EOPNOTSUPP;
-      return -1;
-    }
-    // tcp_listen reallocates the pcb, replace ours
-    pcb_ = listen_pcb;
-    // set callbacks on new pcb
-    LWIP_LOG("tcp_arg(%p)", pcb_);
-    tcp_arg(pcb_, this);
-    tcp_accept(pcb_, LWIPRawImpl::s_accept_fn);
-    return 0;
+    // Regular sockets can't be converted to listening - this shouldn't happen
+    // as listen() should only be called on sockets created for listening
+    errno = EOPNOTSUPP;
+    return -1;
   }
   ssize_t read(void *buf, size_t len) override {
     if (pcb_ == nullptr) {
@@ -491,29 +457,6 @@ class LWIPRawImpl : public Socket {
     return 0;
   }
 
-  err_t accept_fn(struct tcp_pcb *newpcb, err_t err) {
-    LWIP_LOG("accept(newpcb=%p err=%d)", newpcb, err);
-    if (err != ERR_OK || newpcb == nullptr) {
-      // "An error code if there has been an error accepting. Only return ERR_ABRT if you have
-      // called tcp_abort from within the callback function!"
-      // https://www.nongnu.org/lwip/2_1_x/tcp_8h.html#a00517abce6856d6c82f0efebdafb734d
-      // nothing to do here, we just don't push it to the queue
-      return ERR_OK;
-    }
-    // Check if we've reached the maximum accept queue size
-    if (this->accepted_socket_count_ >= MAX_ACCEPTED_SOCKETS) {
-      LWIP_LOG("Rejecting connection, queue full (%d)", this->accepted_socket_count_);
-      // Abort the connection when queue is full
-      tcp_abort(newpcb);
-      // Must return ERR_ABRT since we called tcp_abort()
-      return ERR_ABRT;
-    }
-    auto sock = make_unique<LWIPRawImpl>(family_, newpcb);
-    sock->init();
-    this->accepted_sockets_[this->accepted_socket_count_++] = std::move(sock);
-    LWIP_LOG("Accepted connection, queue size: %d", this->accepted_socket_count_);
-    return ERR_OK;
-  }
   void err_fn(err_t err) {
     LWIP_LOG("err(err=%d)", err);
     // "If a connection is aborted because of an error, the application is alerted of this event by
@@ -545,11 +488,6 @@ class LWIPRawImpl : public Socket {
     return ERR_OK;
   }
 
-  static err_t s_accept_fn(void *arg, struct tcp_pcb *newpcb, err_t err) {
-    LWIPRawImpl *arg_this = reinterpret_cast<LWIPRawImpl *>(arg);
-    return arg_this->accept_fn(newpcb, err);
-  }
-
   static void s_err_fn(void *arg, err_t err) {
     LWIPRawImpl *arg_this = reinterpret_cast<LWIPRawImpl *>(arg);
     arg_this->err_fn(err);
@@ -601,7 +539,107 @@ class LWIPRawImpl : public Socket {
     return -1;
   }
 
+  // Member ordering optimized to minimize padding on 32-bit systems
+  // Largest members first (4 bytes), then smaller members (1 byte each)
   struct tcp_pcb *pcb_;
+  pbuf *rx_buf_ = nullptr;
+  size_t rx_buf_offset_ = 0;
+  bool rx_closed_ = false;
+  // don't use lwip nodelay flag, it sometimes causes reconnect
+  // instead use it for determining whether to call lwip_output
+  bool nodelay_ = false;
+  sa_family_t family_ = 0;
+};
+
+// Listening socket class - only allocates accept queue when needed (for bind+listen sockets)
+// This saves 16 bytes (12 bytes array + 1 byte count + 3 bytes padding) for regular connected sockets on ESP8266/RP2040
+class LWIPRawListenImpl : public LWIPRawImpl {
+ public:
+  LWIPRawListenImpl(sa_family_t family, struct tcp_pcb *pcb) : LWIPRawImpl(family, pcb) {}
+
+  void init() {
+    LWIP_LOG("init(%p)", pcb_);
+    tcp_arg(pcb_, this);
+    tcp_accept(pcb_, LWIPRawListenImpl::s_accept_fn);
+    tcp_err(pcb_, LWIPRawListenImpl::s_err_fn);
+  }
+
+  std::unique_ptr<Socket> accept(struct sockaddr *addr, socklen_t *addrlen) override {
+    if (pcb_ == nullptr) {
+      errno = EBADF;
+      return nullptr;
+    }
+    if (accepted_socket_count_ == 0) {
+      errno = EWOULDBLOCK;
+      return nullptr;
+    }
+    // Take from front for FIFO ordering
+    std::unique_ptr<LWIPRawImpl> sock = std::move(accepted_sockets_[0]);
+    // Shift remaining sockets forward
+    for (uint8_t i = 1; i < accepted_socket_count_; i++) {
+      accepted_sockets_[i - 1] = std::move(accepted_sockets_[i]);
+    }
+    accepted_socket_count_--;
+    LWIP_LOG("Connection accepted by application, queue size: %d", accepted_socket_count_);
+    if (addr != nullptr) {
+      sock->getpeername(addr, addrlen);
+    }
+    LWIP_LOG("accept(%p)", sock.get());
+    return std::unique_ptr<Socket>(std::move(sock));
+  }
+
+  int listen(int backlog) override {
+    if (pcb_ == nullptr) {
+      errno = EBADF;
+      return -1;
+    }
+    LWIP_LOG("tcp_listen_with_backlog(%p backlog=%d)", pcb_, backlog);
+    struct tcp_pcb *listen_pcb = tcp_listen_with_backlog(pcb_, backlog);
+    if (listen_pcb == nullptr) {
+      tcp_abort(pcb_);
+      pcb_ = nullptr;
+      errno = EOPNOTSUPP;
+      return -1;
+    }
+    // tcp_listen reallocates the pcb, replace ours
+    pcb_ = listen_pcb;
+    // set callbacks on new pcb
+    LWIP_LOG("tcp_arg(%p)", pcb_);
+    tcp_arg(pcb_, this);
+    tcp_accept(pcb_, LWIPRawListenImpl::s_accept_fn);
+    return 0;
+  }
+
+ private:
+  err_t accept_fn(struct tcp_pcb *newpcb, err_t err) {
+    LWIP_LOG("accept(newpcb=%p err=%d)", newpcb, err);
+    if (err != ERR_OK || newpcb == nullptr) {
+      // "An error code if there has been an error accepting. Only return ERR_ABRT if you have
+      // called tcp_abort from within the callback function!"
+      // https://www.nongnu.org/lwip/2_1_x/tcp_8h.html#a00517abce6856d6c82f0efebdafb734d
+      // nothing to do here, we just don't push it to the queue
+      return ERR_OK;
+    }
+    // Check if we've reached the maximum accept queue size
+    if (accepted_socket_count_ >= MAX_ACCEPTED_SOCKETS) {
+      LWIP_LOG("Rejecting connection, queue full (%d)", accepted_socket_count_);
+      // Abort the connection when queue is full
+      tcp_abort(newpcb);
+      // Must return ERR_ABRT since we called tcp_abort()
+      return ERR_ABRT;
+    }
+    auto sock = make_unique<LWIPRawImpl>(family_, newpcb);
+    sock->init();
+    accepted_sockets_[accepted_socket_count_++] = std::move(sock);
+    LWIP_LOG("Accepted connection, queue size: %d", accepted_socket_count_);
+    return ERR_OK;
+  }
+
+  static err_t s_accept_fn(void *arg, struct tcp_pcb *newpcb, err_t err) {
+    LWIPRawListenImpl *arg_this = reinterpret_cast<LWIPRawListenImpl *>(arg);
+    return arg_this->accept_fn(newpcb, err);
+  }
+
   // Accept queue - holds incoming connections briefly until the event loop calls accept()
   // This is NOT a connection pool - just a temporary queue between LWIP callbacks and the main loop
   // 3 slots is plenty since connections are pulled out quickly by the event loop
@@ -613,23 +651,21 @@ class LWIPRawImpl : public Socket {
   // - std::array<3>: 12 bytes fixed (3 pointers × 4 bytes)
   // Saves ~44+ bytes RAM per listening socket + avoids ALL heap allocations
   // Used on ESP8266 and RP2040 (platforms using LWIP_TCP implementation)
+  //
+  // By using a separate listening socket class, regular connected sockets save
+  // 16 bytes (12 bytes array + 1 byte count + 3 bytes padding) of memory overhead on 32-bit systems
   static constexpr size_t MAX_ACCEPTED_SOCKETS = 3;
   std::array<std::unique_ptr<LWIPRawImpl>, MAX_ACCEPTED_SOCKETS> accepted_sockets_;
   uint8_t accepted_socket_count_ = 0;  // Number of sockets currently in queue
-  bool rx_closed_ = false;
-  pbuf *rx_buf_ = nullptr;
-  size_t rx_buf_offset_ = 0;
-  // don't use lwip nodelay flag, it sometimes causes reconnect
-  // instead use it for determining whether to call lwip_output
-  bool nodelay_ = false;
-  sa_family_t family_ = 0;
 };
 
 std::unique_ptr<Socket> socket(int domain, int type, int protocol) {
   auto *pcb = tcp_new();
   if (pcb == nullptr)
     return nullptr;
-  auto *sock = new LWIPRawImpl((sa_family_t) domain, pcb);  // NOLINT(cppcoreguidelines-owning-memory)
+  // Create listening socket implementation since user sockets typically bind+listen
+  // Accepted connections are created directly as LWIPRawImpl in the accept callback
+  auto *sock = new LWIPRawListenImpl((sa_family_t) domain, pcb);  // NOLINT(cppcoreguidelines-owning-memory)
   sock->init();
   return std::unique_ptr<Socket>{sock};
 }

From 3f49a61b0320314023ebb182c5ce5b276841d9bf Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Fri, 10 Oct 2025 20:01:16 -1000
Subject: [PATCH 05/90] tweak

---
 esphome/components/socket/lwip_raw_tcp_impl.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/esphome/components/socket/lwip_raw_tcp_impl.cpp b/esphome/components/socket/lwip_raw_tcp_impl.cpp
index 2d23cbc5c6..4dedeffb6a 100644
--- a/esphome/components/socket/lwip_raw_tcp_impl.cpp
+++ b/esphome/components/socket/lwip_raw_tcp_impl.cpp
@@ -561,7 +561,7 @@ class LWIPRawListenImpl : public LWIPRawImpl {
     LWIP_LOG("init(%p)", pcb_);
     tcp_arg(pcb_, this);
     tcp_accept(pcb_, LWIPRawListenImpl::s_accept_fn);
-    tcp_err(pcb_, LWIPRawListenImpl::s_err_fn);
+    tcp_err(pcb_, LWIPRawImpl::s_err_fn);  // Use base class error handler
   }
 
   std::unique_ptr<Socket> accept(struct sockaddr *addr, socklen_t *addrlen) override {

From dacead836f219c3004c236cd2dc6aedea45ecd63 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Fri, 10 Oct 2025 20:59:34 -1000
Subject: [PATCH 06/90] [esp32_ble_tracker] Replace std::vector with
 StaticVector for listeners and clients

---
 .../components/esp32_ble_tracker/__init__.py  | 30 +++++++++++++++++++
 .../esp32_ble_tracker/esp32_ble_tracker.cpp   | 30 ++++++++++++++++++-
 .../esp32_ble_tracker/esp32_ble_tracker.h     | 10 +++++--
 esphome/core/defines.h                        |  2 ++
 4 files changed, 69 insertions(+), 3 deletions(-)

diff --git a/esphome/components/esp32_ble_tracker/__init__.py b/esphome/components/esp32_ble_tracker/__init__.py
index 247496ccd9..8c7f3e3930 100644
--- a/esphome/components/esp32_ble_tracker/__init__.py
+++ b/esphome/components/esp32_ble_tracker/__init__.py
@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+from dataclasses import dataclass
 import logging
 
 from esphome import automation
@@ -52,9 +53,19 @@ class BLEFeatures(StrEnum):
     ESP_BT_DEVICE = "ESP_BT_DEVICE"
 
 
+# Dataclass for registration counts
+@dataclass
+class RegistrationCounts:
+    listeners: int = 0
+    clients: int = 0
+
+
 # Set to track which features are needed by components
 _required_features: set[BLEFeatures] = set()
 
+# Track registration counts for StaticVector sizing
+_registration_counts = RegistrationCounts()
+
 
 def register_ble_features(features: set[BLEFeatures]) -> None:
     """Register BLE features that a component needs.
@@ -257,12 +268,14 @@ async def to_code(config):
         register_ble_features({BLEFeatures.ESP_BT_DEVICE})
 
     for conf in config.get(CONF_ON_BLE_ADVERTISE, []):
+        _registration_counts.listeners += 1
         trigger = cg.new_Pvariable(conf[CONF_TRIGGER_ID], var)
         if CONF_MAC_ADDRESS in conf:
             addr_list = [it.as_hex for it in conf[CONF_MAC_ADDRESS]]
             cg.add(trigger.set_addresses(addr_list))
         await automation.build_automation(trigger, [(ESPBTDeviceConstRef, "x")], conf)
     for conf in config.get(CONF_ON_BLE_SERVICE_DATA_ADVERTISE, []):
+        _registration_counts.listeners += 1
         trigger = cg.new_Pvariable(conf[CONF_TRIGGER_ID], var)
         if len(conf[CONF_SERVICE_UUID]) == len(bt_uuid16_format):
             cg.add(trigger.set_service_uuid16(as_hex(conf[CONF_SERVICE_UUID])))
@@ -275,6 +288,7 @@ async def to_code(config):
             cg.add(trigger.set_address(conf[CONF_MAC_ADDRESS].as_hex))
         await automation.build_automation(trigger, [(adv_data_t_const_ref, "x")], conf)
     for conf in config.get(CONF_ON_BLE_MANUFACTURER_DATA_ADVERTISE, []):
+        _registration_counts.listeners += 1
         trigger = cg.new_Pvariable(conf[CONF_TRIGGER_ID], var)
         if len(conf[CONF_MANUFACTURER_ID]) == len(bt_uuid16_format):
             cg.add(trigger.set_manufacturer_uuid16(as_hex(conf[CONF_MANUFACTURER_ID])))
@@ -287,6 +301,7 @@ async def to_code(config):
             cg.add(trigger.set_address(conf[CONF_MAC_ADDRESS].as_hex))
         await automation.build_automation(trigger, [(adv_data_t_const_ref, "x")], conf)
     for conf in config.get(CONF_ON_SCAN_END, []):
+        _registration_counts.listeners += 1
         trigger = cg.new_Pvariable(conf[CONF_TRIGGER_ID], var)
         await automation.build_automation(trigger, [], conf)
 
@@ -320,6 +335,17 @@ async def _add_ble_features():
         cg.add_define("USE_ESP32_BLE_DEVICE")
         cg.add_define("USE_ESP32_BLE_UUID")
 
+    # Add defines for StaticVector sizing based on registration counts
+    # Only define if count > 0 to avoid allocating unnecessary memory
+    if _registration_counts.listeners > 0:
+        cg.add_define(
+            "ESPHOME_ESP32_BLE_TRACKER_LISTENER_COUNT", _registration_counts.listeners
+        )
+    if _registration_counts.clients > 0:
+        cg.add_define(
+            "ESPHOME_ESP32_BLE_TRACKER_CLIENT_COUNT", _registration_counts.clients
+        )
+
 
 ESP32_BLE_START_SCAN_ACTION_SCHEMA = cv.Schema(
     {
@@ -369,6 +395,7 @@ async def register_ble_device(
     var: cg.SafeExpType, config: ConfigType
 ) -> cg.SafeExpType:
     register_ble_features({BLEFeatures.ESP_BT_DEVICE})
+    _registration_counts.listeners += 1
     paren = await cg.get_variable(config[CONF_ESP32_BLE_ID])
     cg.add(paren.register_listener(var))
     return var
@@ -376,6 +403,7 @@ async def register_ble_device(
 
 async def register_client(var: cg.SafeExpType, config: ConfigType) -> cg.SafeExpType:
     register_ble_features({BLEFeatures.ESP_BT_DEVICE})
+    _registration_counts.clients += 1
     paren = await cg.get_variable(config[CONF_ESP32_BLE_ID])
     cg.add(paren.register_client(var))
     return var
@@ -389,6 +417,7 @@ async def register_raw_ble_device(
     This does NOT register the ESP_BT_DEVICE feature, meaning ESPBTDevice
     will not be compiled in if this is the only registration method used.
     """
+    _registration_counts.listeners += 1
     paren = await cg.get_variable(config[CONF_ESP32_BLE_ID])
     cg.add(paren.register_listener(var))
     return var
@@ -402,6 +431,7 @@ async def register_raw_client(
     This does NOT register the ESP_BT_DEVICE feature, meaning ESPBTDevice
     will not be compiled in if this is the only registration method used.
     """
+    _registration_counts.clients += 1
     paren = await cg.get_variable(config[CONF_ESP32_BLE_ID])
     cg.add(paren.register_client(var))
     return var
diff --git a/esphome/components/esp32_ble_tracker/esp32_ble_tracker.cpp b/esphome/components/esp32_ble_tracker/esp32_ble_tracker.cpp
index 83f59d492e..d07e67825b 100644
--- a/esphome/components/esp32_ble_tracker/esp32_ble_tracker.cpp
+++ b/esphome/components/esp32_ble_tracker/esp32_ble_tracker.cpp
@@ -74,9 +74,11 @@ void ESP32BLETracker::setup() {
       [this](ota::OTAState state, float progress, uint8_t error, ota::OTAComponent *comp) {
         if (state == ota::OTA_STARTED) {
           this->stop_scan();
+#ifdef ESPHOME_ESP32_BLE_TRACKER_CLIENT_COUNT
           for (auto *client : this->clients_) {
             client->disconnect();
           }
+#endif
         }
       });
 #endif
@@ -206,8 +208,10 @@ void ESP32BLETracker::start_scan_(bool first) {
   this->set_scanner_state_(ScannerState::STARTING);
   ESP_LOGD(TAG, "Starting scan, set scanner state to STARTING.");
   if (!first) {
+#ifdef ESPHOME_ESP32_BLE_TRACKER_LISTENER_COUNT
     for (auto *listener : this->listeners_)
       listener->on_scan_end();
+#endif
   }
 #ifdef USE_ESP32_BLE_DEVICE
   this->already_discovered_.clear();
@@ -236,20 +240,25 @@ void ESP32BLETracker::start_scan_(bool first) {
 }
 
 void ESP32BLETracker::register_client(ESPBTClient *client) {
+#ifdef ESPHOME_ESP32_BLE_TRACKER_CLIENT_COUNT
   client->app_id = ++this->app_id_;
   this->clients_.push_back(client);
   this->recalculate_advertisement_parser_types();
+#endif
 }
 
 void ESP32BLETracker::register_listener(ESPBTDeviceListener *listener) {
+#ifdef ESPHOME_ESP32_BLE_TRACKER_LISTENER_COUNT
   listener->set_parent(this);
   this->listeners_.push_back(listener);
   this->recalculate_advertisement_parser_types();
+#endif
 }
 
 void ESP32BLETracker::recalculate_advertisement_parser_types() {
   this->raw_advertisements_ = false;
   this->parse_advertisements_ = false;
+#ifdef ESPHOME_ESP32_BLE_TRACKER_LISTENER_COUNT
   for (auto *listener : this->listeners_) {
     if (listener->get_advertisement_parser_type() == AdvertisementParserType::PARSED_ADVERTISEMENTS) {
       this->parse_advertisements_ = true;
@@ -257,6 +266,8 @@ void ESP32BLETracker::recalculate_advertisement_parser_types() {
       this->raw_advertisements_ = true;
     }
   }
+#endif
+#ifdef ESPHOME_ESP32_BLE_TRACKER_CLIENT_COUNT
   for (auto *client : this->clients_) {
     if (client->get_advertisement_parser_type() == AdvertisementParserType::PARSED_ADVERTISEMENTS) {
       this->parse_advertisements_ = true;
@@ -264,6 +275,7 @@ void ESP32BLETracker::recalculate_advertisement_parser_types() {
       this->raw_advertisements_ = true;
     }
   }
+#endif
 }
 
 void ESP32BLETracker::gap_event_handler(esp_gap_ble_cb_event_t event, esp_ble_gap_cb_param_t *param) {
@@ -282,10 +294,12 @@ void ESP32BLETracker::gap_event_handler(esp_gap_ble_cb_event_t event, esp_ble_ga
     default:
       break;
   }
-  // Forward all events to clients (scan results are handled separately via gap_scan_event_handler)
+    // Forward all events to clients (scan results are handled separately via gap_scan_event_handler)
+#ifdef ESPHOME_ESP32_BLE_TRACKER_CLIENT_COUNT
   for (auto *client : this->clients_) {
     client->gap_event_handler(event, param);
   }
+#endif
 }
 
 void ESP32BLETracker::gap_scan_event_handler(const BLEScanResult &scan_result) {
@@ -348,9 +362,11 @@ void ESP32BLETracker::gap_scan_stop_complete_(const esp_ble_gap_cb_param_t::ble_
 
 void ESP32BLETracker::gattc_event_handler(esp_gattc_cb_event_t event, esp_gatt_if_t gattc_if,
                                           esp_ble_gattc_cb_param_t *param) {
+#ifdef ESPHOME_ESP32_BLE_TRACKER_CLIENT_COUNT
   for (auto *client : this->clients_) {
     client->gattc_event_handler(event, gattc_if, param);
   }
+#endif
 }
 
 void ESP32BLETracker::set_scanner_state_(ScannerState state) {
@@ -704,12 +720,16 @@ bool ESPBTDevice::resolve_irk(const uint8_t *irk) const {
 void ESP32BLETracker::process_scan_result_(const BLEScanResult &scan_result) {
   // Process raw advertisements
   if (this->raw_advertisements_) {
+#ifdef ESPHOME_ESP32_BLE_TRACKER_LISTENER_COUNT
     for (auto *listener : this->listeners_) {
       listener->parse_devices(&scan_result, 1);
     }
+#endif
+#ifdef ESPHOME_ESP32_BLE_TRACKER_CLIENT_COUNT
     for (auto *client : this->clients_) {
       client->parse_devices(&scan_result, 1);
     }
+#endif
   }
 
   // Process parsed advertisements
@@ -719,16 +739,20 @@ void ESP32BLETracker::process_scan_result_(const BLEScanResult &scan_result) {
     device.parse_scan_rst(scan_result);
 
     bool found = false;
+#ifdef ESPHOME_ESP32_BLE_TRACKER_LISTENER_COUNT
     for (auto *listener : this->listeners_) {
       if (listener->parse_device(device))
         found = true;
     }
+#endif
 
+#ifdef ESPHOME_ESP32_BLE_TRACKER_CLIENT_COUNT
     for (auto *client : this->clients_) {
       if (client->parse_device(device)) {
         found = true;
       }
     }
+#endif
 
     if (!found && !this->scan_continuous_) {
       this->print_bt_device_info(device);
@@ -745,8 +769,10 @@ void ESP32BLETracker::cleanup_scan_state_(bool is_stop_complete) {
   // Reset timeout state machine instead of cancelling scheduler timeout
   this->scan_timeout_state_ = ScanTimeoutState::INACTIVE;
 
+#ifdef ESPHOME_ESP32_BLE_TRACKER_LISTENER_COUNT
   for (auto *listener : this->listeners_)
     listener->on_scan_end();
+#endif
 
   this->set_scanner_state_(ScannerState::IDLE);
 }
@@ -770,6 +796,7 @@ void ESP32BLETracker::handle_scanner_failure_() {
 
 void ESP32BLETracker::try_promote_discovered_clients_() {
   // Only promote the first discovered client to avoid multiple simultaneous connections
+#ifdef ESPHOME_ESP32_BLE_TRACKER_CLIENT_COUNT
   for (auto *client : this->clients_) {
     if (client->state() != ClientState::DISCOVERED) {
       continue;
@@ -791,6 +818,7 @@ void ESP32BLETracker::try_promote_discovered_clients_() {
     client->connect();
     break;
   }
+#endif
 }
 
 const char *ESP32BLETracker::scanner_state_to_string_(ScannerState state) const {
diff --git a/esphome/components/esp32_ble_tracker/esp32_ble_tracker.h b/esphome/components/esp32_ble_tracker/esp32_ble_tracker.h
index e53c2ac097..f80f3e2670 100644
--- a/esphome/components/esp32_ble_tracker/esp32_ble_tracker.h
+++ b/esphome/components/esp32_ble_tracker/esp32_ble_tracker.h
@@ -302,6 +302,7 @@ class ESP32BLETracker : public Component,
   /// Count clients in each state
   ClientStateCounts count_client_states_() const {
     ClientStateCounts counts;
+#ifdef ESPHOME_ESP32_BLE_TRACKER_CLIENT_COUNT
     for (auto *client : this->clients_) {
       switch (client->state()) {
         case ClientState::DISCONNECTING:
@@ -317,12 +318,17 @@ class ESP32BLETracker : public Component,
           break;
       }
     }
+#endif
     return counts;
   }
 
   // Group 1: Large objects (12+ bytes) - vectors and callback manager
-  std::vector<ESPBTDeviceListener *> listeners_;
-  std::vector<ESPBTClient *> clients_;
+#ifdef ESPHOME_ESP32_BLE_TRACKER_LISTENER_COUNT
+  StaticVector<ESPBTDeviceListener *, ESPHOME_ESP32_BLE_TRACKER_LISTENER_COUNT> listeners_;
+#endif
+#ifdef ESPHOME_ESP32_BLE_TRACKER_CLIENT_COUNT
+  StaticVector<ESPBTClient *, ESPHOME_ESP32_BLE_TRACKER_CLIENT_COUNT> clients_;
+#endif
   CallbackManager<void(ScannerState)> scanner_state_callbacks_;
 #ifdef USE_ESP32_BLE_DEVICE
   /// Vector of addresses that have already been printed in print_bt_device_info
diff --git a/esphome/core/defines.h b/esphome/core/defines.h
index 0f1d1bcf28..955d0f987c 100644
--- a/esphome/core/defines.h
+++ b/esphome/core/defines.h
@@ -175,6 +175,8 @@
 #define USE_ESP32_BLE_SERVER_DESCRIPTOR_ON_WRITE
 #define USE_ESP32_BLE_SERVER_ON_CONNECT
 #define USE_ESP32_BLE_SERVER_ON_DISCONNECT
+#define ESPHOME_ESP32_BLE_TRACKER_LISTENER_COUNT 1
+#define ESPHOME_ESP32_BLE_TRACKER_CLIENT_COUNT 1
 #define USE_ESP32_CAMERA_JPEG_ENCODER
 #define USE_I2C
 #define USE_IMPROV

From 460c41d9b880644efbb97000b44ba808cac0988c Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Sat, 11 Oct 2025 05:53:14 -1000
Subject: [PATCH 07/90] [usb_host] Fix transfer slot exhaustion at high data
 rates and add configurable max_transfer_requests

---
 esphome/components/usb_host/__init__.py       |  8 +++
 esphome/components/usb_host/usb_host.h        | 37 ++++++------
 .../components/usb_host/usb_host_client.cpp   | 56 ++++++-------------
 esphome/core/defines.h                        |  1 +
 4 files changed, 45 insertions(+), 57 deletions(-)

diff --git a/esphome/components/usb_host/__init__.py b/esphome/components/usb_host/__init__.py
index de734bf425..42c893d296 100644
--- a/esphome/components/usb_host/__init__.py
+++ b/esphome/components/usb_host/__init__.py
@@ -20,6 +20,7 @@ USBClient = usb_host_ns.class_("USBClient", Component)
 CONF_VID = "vid"
 CONF_PID = "pid"
 CONF_ENABLE_HUBS = "enable_hubs"
+CONF_MAX_TRANSFER_REQUESTS = "max_transfer_requests"
 
 
 def usb_device_schema(cls=USBClient, vid: int = None, pid: [int] = None) -> cv.Schema:
@@ -44,6 +45,9 @@ CONFIG_SCHEMA = cv.All(
         {
             cv.GenerateID(): cv.declare_id(USBHost),
             cv.Optional(CONF_ENABLE_HUBS, default=False): cv.boolean,
+            cv.Optional(CONF_MAX_TRANSFER_REQUESTS, default=16): cv.int_range(
+                min=1, max=32
+            ),
             cv.Optional(CONF_DEVICES): cv.ensure_list(usb_device_schema()),
         }
     ),
@@ -62,6 +66,10 @@ async def to_code(config):
     add_idf_sdkconfig_option("CONFIG_USB_HOST_CONTROL_TRANSFER_MAX_SIZE", 1024)
     if config.get(CONF_ENABLE_HUBS):
         add_idf_sdkconfig_option("CONFIG_USB_HOST_HUBS_SUPPORTED", True)
+
+    max_requests = config[CONF_MAX_TRANSFER_REQUESTS]
+    cg.add_define("USB_HOST_MAX_REQUESTS", max_requests)
+
     var = cg.new_Pvariable(config[CONF_ID])
     await cg.register_component(var, config)
     for device in config.get(CONF_DEVICES) or ():
diff --git a/esphome/components/usb_host/usb_host.h b/esphome/components/usb_host/usb_host.h
index 4f8d2ec9a8..3ccc49a5a0 100644
--- a/esphome/components/usb_host/usb_host.h
+++ b/esphome/components/usb_host/usb_host.h
@@ -16,23 +16,25 @@ namespace usb_host {
 
 // THREADING MODEL:
 // This component uses a dedicated USB task for event processing to prevent data loss.
-// - USB Task (high priority): Handles USB events, executes transfer callbacks
-// - Main Loop Task: Initiates transfers, processes completion events
+// - USB Task (high priority): Handles USB events, executes transfer callbacks, releases transfer slots
+// - Main Loop Task: Initiates transfers, processes device connect/disconnect events
 //
 // Thread-safe communication:
 // - Lock-free queues for USB task -> main loop events (SPSC pattern)
-// - Lock-free TransferRequest pool using atomic bitmask (MCSP pattern)
+// - Lock-free TransferRequest pool using atomic bitmask (MCMP pattern - multi-consumer, multi-producer)
 //
 // TransferRequest pool access pattern:
 // - get_trq_() [allocate]: Called from BOTH USB task and main loop threads
 //   * USB task: via USB UART input callbacks that restart transfers immediately
 //   * Main loop: for output transfers and flow-controlled input restarts
-// - release_trq() [deallocate]: Called from main loop thread only
+// - release_trq() [deallocate]: Called from BOTH USB task and main loop threads
+//   * USB task: immediately after transfer callback completes (critical for preventing slot exhaustion)
+//   * Main loop: when transfer submission fails
 //
-// The multi-threaded allocation is intentional for performance:
-// - USB task can immediately restart input transfers without context switching
+// The multi-threaded allocation/deallocation is intentional for performance:
+// - USB task can immediately restart input transfers and release slots without context switching
 // - Main loop controls backpressure by deciding when to restart after consuming data
-// The atomic bitmask ensures thread-safe allocation without mutex blocking.
+// The atomic bitmask ensures thread-safe allocation/deallocation without mutex blocking.
 
 static const char *const TAG = "usb_host";
 
@@ -52,8 +54,13 @@ static const uint8_t USB_DIR_IN = 1 << 7;
 static const uint8_t USB_DIR_OUT = 0;
 static const size_t SETUP_PACKET_SIZE = 8;
 
-static const size_t MAX_REQUESTS = 16;  // maximum number of outstanding requests possible.
-static_assert(MAX_REQUESTS <= 16, "MAX_REQUESTS must be <= 16 to fit in uint16_t bitmask");
+static const size_t MAX_REQUESTS = USB_HOST_MAX_REQUESTS;  // maximum number of outstanding requests possible.
+static_assert(MAX_REQUESTS >= 1 && MAX_REQUESTS <= 32, "MAX_REQUESTS must be between 1 and 32");
+
+// Select appropriate bitmask type based on MAX_REQUESTS
+// uint16_t for <= 16 requests, uint32_t for 17-32 requests
+using trq_bitmask_t = std::conditional<(MAX_REQUESTS <= 16), uint16_t, uint32_t>::type;
+
 static constexpr size_t USB_EVENT_QUEUE_SIZE = 32;   // Size of event queue between USB task and main loop
 static constexpr size_t USB_TASK_STACK_SIZE = 4096;  // Stack size for USB task (same as ESP-IDF USB examples)
 static constexpr UBaseType_t USB_TASK_PRIORITY = 5;  // Higher priority than main loop (tskIDLE_PRIORITY + 5)
@@ -83,8 +90,6 @@ struct TransferRequest {
 enum EventType : uint8_t {
   EVENT_DEVICE_NEW,
   EVENT_DEVICE_GONE,
-  EVENT_TRANSFER_COMPLETE,
-  EVENT_CONTROL_COMPLETE,
 };
 
 struct UsbEvent {
@@ -96,9 +101,6 @@ struct UsbEvent {
     struct {
       usb_device_handle_t handle;
     } device_gone;
-    struct {
-      TransferRequest *trq;
-    } transfer;
   } data;
 
   // Required for EventPool - no cleanup needed for POD types
@@ -163,10 +165,9 @@ class USBClient : public Component {
   uint16_t pid_{};
   // Lock-free pool management using atomic bitmask (no dynamic allocation)
   // Bit i = 1: requests_[i] is in use, Bit i = 0: requests_[i] is available
-  // Supports multiple concurrent consumers (both threads can allocate)
-  // Single producer for deallocation (main loop only)
-  // Limited to 16 slots by uint16_t size (enforced by static_assert)
-  std::atomic<uint16_t> trq_in_use_;
+  // Supports multiple concurrent consumers and producers (both threads can allocate/deallocate)
+  // Bitmask type automatically selected: uint16_t for <= 16 slots, uint32_t for 17-32 slots
+  std::atomic<trq_bitmask_t> trq_in_use_;
   TransferRequest requests_[MAX_REQUESTS]{};
 };
 class USBHost : public Component {
diff --git a/esphome/components/usb_host/usb_host_client.cpp b/esphome/components/usb_host/usb_host_client.cpp
index b26385a8ef..5c8874861e 100644
--- a/esphome/components/usb_host/usb_host_client.cpp
+++ b/esphome/components/usb_host/usb_host_client.cpp
@@ -228,12 +228,6 @@ void USBClient::loop() {
       case EVENT_DEVICE_GONE:
         this->on_removed(event->data.device_gone.handle);
         break;
-      case EVENT_TRANSFER_COMPLETE:
-      case EVENT_CONTROL_COMPLETE: {
-        auto *trq = event->data.transfer.trq;
-        this->release_trq(trq);
-        break;
-      }
     }
     // Return event to pool for reuse
     this->event_pool.release(event);
@@ -313,25 +307,6 @@ void USBClient::on_removed(usb_device_handle_t handle) {
   }
 }
 
-// Helper to queue transfer cleanup to main loop
-static void queue_transfer_cleanup(TransferRequest *trq, EventType type) {
-  auto *client = trq->client;
-
-  // Allocate event from pool
-  UsbEvent *event = client->event_pool.allocate();
-  if (event == nullptr) {
-    // No events available - increment counter for periodic logging
-    client->event_queue.increment_dropped_count();
-    return;
-  }
-
-  event->type = type;
-  event->data.transfer.trq = trq;
-
-  // Push to lock-free queue (always succeeds since pool size == queue size)
-  client->event_queue.push(event);
-}
-
 // CALLBACK CONTEXT: USB task (called from usb_host_client_handle_events in USB task)
 static void control_callback(const usb_transfer_t *xfer) {
   auto *trq = static_cast<TransferRequest *>(xfer->context);
@@ -346,8 +321,9 @@ static void control_callback(const usb_transfer_t *xfer) {
     trq->callback(trq->status);
   }
 
-  // Queue cleanup to main loop
-  queue_transfer_cleanup(trq, EVENT_CONTROL_COMPLETE);
+  // Release transfer slot immediately in USB task
+  // The release_trq() uses thread-safe atomic operations
+  trq->client->release_trq(trq);
 }
 
 // THREAD CONTEXT: Called from both USB task and main loop threads (multi-consumer)
@@ -358,20 +334,20 @@ static void control_callback(const usb_transfer_t *xfer) {
 // This multi-threaded access is intentional for performance - USB task can
 // immediately restart transfers without waiting for main loop scheduling.
 TransferRequest *USBClient::get_trq_() {
-  uint16_t mask = this->trq_in_use_.load(std::memory_order_relaxed);
+  trq_bitmask_t mask = this->trq_in_use_.load(std::memory_order_relaxed);
 
   // Find first available slot (bit = 0) and try to claim it atomically
   // We use a while loop to allow retrying the same slot after CAS failure
   size_t i = 0;
   while (i != MAX_REQUESTS) {
-    if (mask & (1U << i)) {
+    if (mask & (static_cast<trq_bitmask_t>(1) << i)) {
       // Slot is in use, move to next slot
       i++;
       continue;
     }
 
     // Slot i appears available, try to claim it atomically
-    uint16_t desired = mask | (1U << i);  // Set bit i to mark as in-use
+    trq_bitmask_t desired = mask | (static_cast<trq_bitmask_t>(1) << i);  // Set bit i to mark as in-use
 
     if (this->trq_in_use_.compare_exchange_weak(mask, desired, std::memory_order_acquire, std::memory_order_relaxed)) {
       // Successfully claimed slot i - prepare the TransferRequest
@@ -386,7 +362,7 @@ TransferRequest *USBClient::get_trq_() {
     i = 0;
   }
 
-  ESP_LOGE(TAG, "All %d transfer slots in use", MAX_REQUESTS);
+  ESP_LOGE(TAG, "All %zu transfer slots in use", MAX_REQUESTS);
   return nullptr;
 }
 void USBClient::disconnect() {
@@ -452,8 +428,10 @@ static void transfer_callback(usb_transfer_t *xfer) {
     trq->callback(trq->status);
   }
 
-  // Queue cleanup to main loop
-  queue_transfer_cleanup(trq, EVENT_TRANSFER_COMPLETE);
+  // Release transfer slot immediately in USB task to prevent slot exhaustion
+  // This is critical for high-throughput transfers (e.g., USB UART at 115200 baud)
+  // The release_trq() uses thread-safe atomic operations
+  trq->client->release_trq(trq);
 }
 /**
  * Performs a transfer input operation.
@@ -521,12 +499,12 @@ void USBClient::dump_config() {
                 "  Product id %04X",
                 this->vid_, this->pid_);
 }
-// THREAD CONTEXT: Only called from main loop thread (single producer for deallocation)
-// - Via event processing when handling EVENT_TRANSFER_COMPLETE/EVENT_CONTROL_COMPLETE
-// - Directly when transfer submission fails
+// THREAD CONTEXT: Called from both USB task and main loop threads
+// - USB task: Immediately after transfer callback completes
+// - Main loop: When transfer submission fails
 //
 // THREAD SAFETY: Lock-free using atomic AND to clear bit
-// Single-producer pattern makes this simpler than allocation
+// Thread-safe atomic operation allows multi-threaded deallocation
 void USBClient::release_trq(TransferRequest *trq) {
   if (trq == nullptr)
     return;
@@ -540,8 +518,8 @@ void USBClient::release_trq(TransferRequest *trq) {
 
   // Atomically clear bit i to mark slot as available
   // fetch_and with inverted bitmask clears the bit atomically
-  uint16_t bit = 1U << index;
-  this->trq_in_use_.fetch_and(static_cast<uint16_t>(~bit), std::memory_order_release);
+  trq_bitmask_t bit = static_cast<trq_bitmask_t>(1) << index;
+  this->trq_in_use_.fetch_and(static_cast<trq_bitmask_t>(~bit), std::memory_order_release);
 }
 
 }  // namespace usb_host
diff --git a/esphome/core/defines.h b/esphome/core/defines.h
index 0f1d1bcf28..620f15765e 100644
--- a/esphome/core/defines.h
+++ b/esphome/core/defines.h
@@ -191,6 +191,7 @@
 #define USE_WEBSERVER_PORT 80  // NOLINT
 #define USE_WEBSERVER_SORTING
 #define USE_WIFI_11KV_SUPPORT
+#define USB_HOST_MAX_REQUESTS 16
 
 #ifdef USE_ARDUINO
 #define USE_ARDUINO_VERSION_CODE VERSION_CODE(3, 2, 1)

From dd6085456a5fba720a96bd77060d10163153ebed Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Sat, 11 Oct 2025 06:00:57 -1000
Subject: [PATCH 08/90] tweak

---
 esphome/components/usb_host/__init__.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/esphome/components/usb_host/__init__.py b/esphome/components/usb_host/__init__.py
index 42c893d296..d452e0e9fa 100644
--- a/esphome/components/usb_host/__init__.py
+++ b/esphome/components/usb_host/__init__.py
@@ -9,6 +9,7 @@ from esphome.components.esp32 import (
 import esphome.config_validation as cv
 from esphome.const import CONF_DEVICES, CONF_ID
 from esphome.cpp_types import Component
+from esphome.types import ConfigType
 
 AUTO_LOAD = ["bytebuffer"]
 CODEOWNERS = ["@clydebarrow"]
@@ -62,7 +63,7 @@ async def register_usb_client(config):
     return var
 
 
-async def to_code(config):
+async def to_code(config: ConfigType) -> None:
     add_idf_sdkconfig_option("CONFIG_USB_HOST_CONTROL_TRANSFER_MAX_SIZE", 1024)
     if config.get(CONF_ENABLE_HUBS):
         add_idf_sdkconfig_option("CONFIG_USB_HOST_HUBS_SUPPORTED", True)

From 442a60766d089aec8714ecb5ebcd7b9e06a3ea70 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Sat, 11 Oct 2025 06:02:49 -1000
Subject: [PATCH 09/90] missing defines

---
 esphome/components/usb_host/usb_host.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/esphome/components/usb_host/usb_host.h b/esphome/components/usb_host/usb_host.h
index 3ccc49a5a0..036c535bd7 100644
--- a/esphome/components/usb_host/usb_host.h
+++ b/esphome/components/usb_host/usb_host.h
@@ -2,6 +2,7 @@
 
 // Should not be needed, but it's required to pass CI clang-tidy checks
 #if defined(USE_ESP32_VARIANT_ESP32S2) || defined(USE_ESP32_VARIANT_ESP32S3) || defined(USE_ESP32_VARIANT_ESP32P4)
+#include "esphome/core/defines.h"
 #include "esphome/core/component.h"
 #include <vector>
 #include "usb/usb_host.h"

From 2796cac9727ac53d555cac2269299384051f7168 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Sat, 11 Oct 2025 06:17:36 -1000
Subject: [PATCH 10/90] compile tests

---
 tests/components/usb_host/test.esp32-s3-idf.yaml | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tests/components/usb_host/test.esp32-s3-idf.yaml b/tests/components/usb_host/test.esp32-s3-idf.yaml
index a2892872e5..5360d1f6ff 100644
--- a/tests/components/usb_host/test.esp32-s3-idf.yaml
+++ b/tests/components/usb_host/test.esp32-s3-idf.yaml
@@ -1,4 +1,5 @@
 usb_host:
+  max_transfer_requests: 32  # Test uint32_t bitmask path (17-32 requests)
   devices:
     - id: device_1
       vid: 0x1234

From ec71669bff4f645b968793fa683e411cb7aae253 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Sat, 11 Oct 2025 06:24:35 -1000
Subject: [PATCH 11/90] tweak comments

---
 esphome/components/usb_host/usb_host_client.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/esphome/components/usb_host/usb_host_client.cpp b/esphome/components/usb_host/usb_host_client.cpp
index 5c8874861e..91d7af2898 100644
--- a/esphome/components/usb_host/usb_host_client.cpp
+++ b/esphome/components/usb_host/usb_host_client.cpp
@@ -428,8 +428,8 @@ static void transfer_callback(usb_transfer_t *xfer) {
     trq->callback(trq->status);
   }
 
-  // Release transfer slot immediately in USB task to prevent slot exhaustion
-  // This is critical for high-throughput transfers (e.g., USB UART at 115200 baud)
+  // Release transfer slot AFTER callback completes to prevent slot exhaustion
+  // The callback has finished accessing xfer->data_buffer, so it's safe to release
   // The release_trq() uses thread-safe atomic operations
   trq->client->release_trq(trq);
 }

From fa69b74e6c10e4fb0bfbd67c11cdca7ef1bd2d18 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Sat, 11 Oct 2025 06:25:44 -1000
Subject: [PATCH 12/90] tweak comments

---
 esphome/components/usb_host/usb_host_client.cpp | 1 +
 1 file changed, 1 insertion(+)

diff --git a/esphome/components/usb_host/usb_host_client.cpp b/esphome/components/usb_host/usb_host_client.cpp
index 91d7af2898..2139ed869a 100644
--- a/esphome/components/usb_host/usb_host_client.cpp
+++ b/esphome/components/usb_host/usb_host_client.cpp
@@ -429,6 +429,7 @@ static void transfer_callback(usb_transfer_t *xfer) {
   }
 
   // Release transfer slot AFTER callback completes to prevent slot exhaustion
+  // This is critical for high-throughput transfers (e.g., USB UART at 115200 baud)
   // The callback has finished accessing xfer->data_buffer, so it's safe to release
   // The release_trq() uses thread-safe atomic operations
   trq->client->release_trq(trq);

From 6273380407e60d0f197b8b84e6d92c7d4d5e9526 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Sat, 11 Oct 2025 10:51:17 -1000
Subject: [PATCH 13/90] [core] Add make_name_with_suffix helper to optimize
 string concatenation

---
 esphome/components/esp32_ble/ble.cpp          |  3 +--
 .../ethernet/ethernet_component.cpp           |  2 +-
 esphome/components/mqtt/mqtt_client.cpp       |  2 +-
 esphome/components/wifi/wifi_component.cpp    |  2 +-
 esphome/config_validation.py                  |  7 ++++++
 esphome/core/application.h                    |  6 +++--
 esphome/core/config.py                        |  2 +-
 esphome/core/helpers.cpp                      | 22 +++++++++++++++++++
 esphome/core/helpers.h                        |  9 ++++++++
 9 files changed, 47 insertions(+), 8 deletions(-)

diff --git a/esphome/components/esp32_ble/ble.cpp b/esphome/components/esp32_ble/ble.cpp
index 0c340c55cc..e37b45fe71 100644
--- a/esphome/components/esp32_ble/ble.cpp
+++ b/esphome/components/esp32_ble/ble.cpp
@@ -213,8 +213,7 @@ bool ESP32BLE::ble_setup_() {
   if (this->name_.has_value()) {
     name = this->name_.value();
     if (App.is_name_add_mac_suffix_enabled()) {
-      name += "-";
-      name += get_mac_address().substr(6);
+      name = make_name_with_suffix(name, '-', get_mac_address().substr(6));
     }
   } else {
     name = App.get_name();
diff --git a/esphome/components/ethernet/ethernet_component.cpp b/esphome/components/ethernet/ethernet_component.cpp
index 28043dd969..5f28d6db25 100644
--- a/esphome/components/ethernet/ethernet_component.cpp
+++ b/esphome/components/ethernet/ethernet_component.cpp
@@ -691,7 +691,7 @@ void EthernetComponent::set_manual_ip(const ManualIP &manual_ip) { this->manual_
 
 std::string EthernetComponent::get_use_address() const {
   if (this->use_address_.empty()) {
-    return App.get_name() + ".local";
+    return make_name_with_suffix(App.get_name(), '.', "local");
   }
   return this->use_address_;
 }
diff --git a/esphome/components/mqtt/mqtt_client.cpp b/esphome/components/mqtt/mqtt_client.cpp
index 7ab6efd1a1..3642ddb38e 100644
--- a/esphome/components/mqtt/mqtt_client.cpp
+++ b/esphome/components/mqtt/mqtt_client.cpp
@@ -29,7 +29,7 @@ static const char *const TAG = "mqtt";
 
 MQTTClientComponent::MQTTClientComponent() {
   global_mqtt_client = this;
-  this->credentials_.client_id = App.get_name() + "-" + get_mac_address();
+  this->credentials_.client_id = make_name_with_suffix(App.get_name(), '-', get_mac_address());
 }
 
 // Connection
diff --git a/esphome/components/wifi/wifi_component.cpp b/esphome/components/wifi/wifi_component.cpp
index 2e083d4c68..ec8687e927 100644
--- a/esphome/components/wifi/wifi_component.cpp
+++ b/esphome/components/wifi/wifi_component.cpp
@@ -267,7 +267,7 @@ network::IPAddress WiFiComponent::get_dns_address(int num) {
 }
 std::string WiFiComponent::get_use_address() const {
   if (this->use_address_.empty()) {
-    return App.get_name() + ".local";
+    return make_name_with_suffix(App.get_name(), '.', "local");
   }
   return this->use_address_;
 }
diff --git a/esphome/config_validation.py b/esphome/config_validation.py
index 7aaba886e3..2746f574ba 100644
--- a/esphome/config_validation.py
+++ b/esphome/config_validation.py
@@ -1195,6 +1195,13 @@ def validate_bytes(value):
 
 
 def hostname(value):
+    """Validate that the value is a valid hostname.
+
+    Maximum length is 63 characters per RFC 1035.
+
+    Note: If this limit is changed, update MAX_NAME_WITH_SUFFIX_SIZE in
+    esphome/core/application.h to accommodate the new maximum length.
+    """
     value = string(value)
     if re.match(r"^[a-z0-9-]{1,63}$", value, re.IGNORECASE) is not None:
         return value
diff --git a/esphome/core/application.h b/esphome/core/application.h
index 1f22499051..47e902a191 100644
--- a/esphome/core/application.h
+++ b/esphome/core/application.h
@@ -103,8 +103,10 @@ class Application {
     this->name_add_mac_suffix_ = name_add_mac_suffix;
     if (name_add_mac_suffix) {
       const std::string mac_suffix = get_mac_address().substr(6);
-      this->name_ = name + "-" + mac_suffix;
-      this->friendly_name_ = friendly_name.empty() ? "" : friendly_name + " " + mac_suffix;
+      this->name_ = make_name_with_suffix(name, '-', mac_suffix);
+      if (!friendly_name.empty()) {
+        this->friendly_name_ = make_name_with_suffix(friendly_name, ' ', mac_suffix);
+      }
     } else {
       this->name_ = name;
       this->friendly_name_ = friendly_name;
diff --git a/esphome/core/config.py b/esphome/core/config.py
index 7bf7f82a8b..8a5876dbcf 100644
--- a/esphome/core/config.py
+++ b/esphome/core/config.py
@@ -200,7 +200,7 @@ CONFIG_SCHEMA = cv.All(
     cv.Schema(
         {
             cv.Required(CONF_NAME): cv.valid_name,
-            cv.Optional(CONF_FRIENDLY_NAME, ""): cv.string,
+            cv.Optional(CONF_FRIENDLY_NAME, ""): cv.All(cv.string, cv.Length(max=120)),
             cv.Optional(CONF_AREA): validate_area_config,
             cv.Optional(CONF_COMMENT): cv.string,
             cv.Required(CONF_BUILD_PATH): cv.string,
diff --git a/esphome/core/helpers.cpp b/esphome/core/helpers.cpp
index d4f6809776..82dbeddf22 100644
--- a/esphome/core/helpers.cpp
+++ b/esphome/core/helpers.cpp
@@ -235,6 +235,28 @@ std::string str_sprintf(const char *fmt, ...) {
   return str;
 }
 
+// Maximum size for name with suffix: 120 (max friendly name) + 1 (separator) + 6 (MAC suffix) + 1 (null term)
+static constexpr size_t MAX_NAME_WITH_SUFFIX_SIZE = 128;
+
+std::string make_name_with_suffix(const std::string &name, char sep, const std::string &suffix) {
+  char buffer[MAX_NAME_WITH_SUFFIX_SIZE];
+  size_t name_len = name.size();
+  size_t suffix_len = suffix.size();
+  size_t total_len = name_len + 1 + suffix_len;
+
+  // Silently truncate if needed: prioritize keeping the full suffix
+  if (total_len >= MAX_NAME_WITH_SUFFIX_SIZE) {
+    name_len = MAX_NAME_WITH_SUFFIX_SIZE - suffix_len - 2;  // -2 for separator and null terminator
+    total_len = name_len + 1 + suffix_len;
+  }
+
+  memcpy(buffer, name.c_str(), name_len);
+  buffer[name_len] = sep;
+  memcpy(buffer + name_len + 1, suffix.c_str(), suffix_len);
+  buffer[total_len] = '\0';
+  return std::string(buffer, total_len);
+}
+
 // Parsing & formatting
 
 size_t parse_hex(const char *str, size_t length, uint8_t *data, size_t count) {
diff --git a/esphome/core/helpers.h b/esphome/core/helpers.h
index e06f2d15ef..f64c14aa85 100644
--- a/esphome/core/helpers.h
+++ b/esphome/core/helpers.h
@@ -306,6 +306,15 @@ std::string __attribute__((format(printf, 1, 3))) str_snprintf(const char *fmt,
 /// sprintf-like function returning std::string.
 std::string __attribute__((format(printf, 1, 2))) str_sprintf(const char *fmt, ...);
 
+/// Concatenate a name with a separator and suffix using an efficient stack-based approach.
+/// This avoids multiple heap allocations during string construction.
+/// Maximum name length supported is 120 characters for friendly names.
+/// @param name The base name string
+/// @param sep The separator character (e.g., '-', ' ', or '.')
+/// @param suffix The suffix to append (e.g., MAC address suffix or ".local")
+/// @return The concatenated string: name + sep + suffix
+std::string make_name_with_suffix(const std::string &name, char sep, const std::string &suffix);
+
 ///@}
 
 /// @name Parsing & formatting

From 1acbb007dd1709e60482f75c113febc71b3ad92e Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Sat, 11 Oct 2025 11:08:47 -1000
Subject: [PATCH 14/90] [ci] Filter out components without tests from CI test
 jobs (#11134 followup)

---
 .github/workflows/ci.yml            |  6 ++-
 script/determine-jobs.py            | 13 ++++-
 tests/script/test_determine_jobs.py | 75 ++++++++++++++++++++++++++++-
 3 files changed, 89 insertions(+), 5 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 4451007da0..f692b1f7d0 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -177,6 +177,7 @@ jobs:
       clang-tidy: ${{ steps.determine.outputs.clang-tidy }}
       python-linters: ${{ steps.determine.outputs.python-linters }}
       changed-components: ${{ steps.determine.outputs.changed-components }}
+      changed-components-with-tests: ${{ steps.determine.outputs.changed-components-with-tests }}
       component-test-count: ${{ steps.determine.outputs.component-test-count }}
     steps:
       - name: Check out code from GitHub
@@ -204,6 +205,7 @@ jobs:
           echo "clang-tidy=$(echo "$output" | jq -r '.clang_tidy')" >> $GITHUB_OUTPUT
           echo "python-linters=$(echo "$output" | jq -r '.python_linters')" >> $GITHUB_OUTPUT
           echo "changed-components=$(echo "$output" | jq -c '.changed_components')" >> $GITHUB_OUTPUT
+          echo "changed-components-with-tests=$(echo "$output" | jq -c '.changed_components_with_tests')" >> $GITHUB_OUTPUT
           echo "component-test-count=$(echo "$output" | jq -r '.component_test_count')" >> $GITHUB_OUTPUT
 
   integration-tests:
@@ -367,7 +369,7 @@ jobs:
       fail-fast: false
       max-parallel: 2
       matrix:
-        file: ${{ fromJson(needs.determine-jobs.outputs.changed-components) }}
+        file: ${{ fromJson(needs.determine-jobs.outputs.changed-components-with-tests) }}
     steps:
       - name: Cache apt packages
         uses: awalsh128/cache-apt-pkgs-action@acb598e5ddbc6f68a970c5da0688d2f3a9f04d05 # v1.5.3
@@ -414,7 +416,7 @@ jobs:
           . venv/bin/activate
 
           # Use intelligent splitter that groups components with same bus configs
-          components='${{ needs.determine-jobs.outputs.changed-components }}'
+          components='${{ needs.determine-jobs.outputs.changed-components-with-tests }}'
 
           echo "Splitting components intelligently..."
           output=$(python3 script/split_components_for_ci.py --components "$components" --batch-size 40 --output github)
diff --git a/script/determine-jobs.py b/script/determine-jobs.py
index e26bc29c2f..a078fd8f9b 100755
--- a/script/determine-jobs.py
+++ b/script/determine-jobs.py
@@ -237,6 +237,16 @@ def main() -> None:
     result = subprocess.run(cmd, capture_output=True, text=True, check=True)
     changed_components = parse_list_components_output(result.stdout)
 
+    # Filter to only components that have test files
+    # Components without tests shouldn't generate CI test jobs
+    tests_dir = Path(root_path) / "tests" / "components"
+    changed_components_with_tests = [
+        component
+        for component in changed_components
+        if (component_test_dir := tests_dir / component).exists()
+        and any(component_test_dir.glob("test.*.yaml"))
+    ]
+
     # Build output
     output: dict[str, Any] = {
         "integration_tests": run_integration,
@@ -244,7 +254,8 @@ def main() -> None:
         "clang_format": run_clang_format,
         "python_linters": run_python_linters,
         "changed_components": changed_components,
-        "component_test_count": len(changed_components),
+        "changed_components_with_tests": changed_components_with_tests,
+        "component_test_count": len(changed_components_with_tests),
     }
 
     # Output as JSON
diff --git a/tests/script/test_determine_jobs.py b/tests/script/test_determine_jobs.py
index 7200afc2ee..5d8746f434 100644
--- a/tests/script/test_determine_jobs.py
+++ b/tests/script/test_determine_jobs.py
@@ -4,6 +4,7 @@ from collections.abc import Generator
 import importlib.util
 import json
 import os
+from pathlib import Path
 import subprocess
 import sys
 from unittest.mock import Mock, call, patch
@@ -90,7 +91,13 @@ def test_main_all_tests_should_run(
     assert output["clang_format"] is True
     assert output["python_linters"] is True
     assert output["changed_components"] == ["wifi", "api", "sensor"]
-    assert output["component_test_count"] == 3
+    # changed_components_with_tests will only include components that actually have test files
+    assert "changed_components_with_tests" in output
+    assert isinstance(output["changed_components_with_tests"], list)
+    # component_test_count matches number of components with tests
+    assert output["component_test_count"] == len(
+        output["changed_components_with_tests"]
+    )
 
 
 def test_main_no_tests_should_run(
@@ -125,6 +132,7 @@ def test_main_no_tests_should_run(
     assert output["clang_format"] is False
     assert output["python_linters"] is False
     assert output["changed_components"] == []
+    assert output["changed_components_with_tests"] == []
     assert output["component_test_count"] == 0
 
 
@@ -197,7 +205,13 @@ def test_main_with_branch_argument(
     assert output["clang_format"] is False
     assert output["python_linters"] is True
     assert output["changed_components"] == ["mqtt"]
-    assert output["component_test_count"] == 1
+    # changed_components_with_tests will only include components that actually have test files
+    assert "changed_components_with_tests" in output
+    assert isinstance(output["changed_components_with_tests"], list)
+    # component_test_count matches number of components with tests
+    assert output["component_test_count"] == len(
+        output["changed_components_with_tests"]
+    )
 
 
 def test_should_run_integration_tests(
@@ -377,3 +391,60 @@ def test_should_run_clang_format_with_branch() -> None:
         mock_changed.return_value = []
         determine_jobs.should_run_clang_format("release")
         mock_changed.assert_called_once_with("release")
+
+
+def test_main_filters_components_without_tests(
+    mock_should_run_integration_tests: Mock,
+    mock_should_run_clang_tidy: Mock,
+    mock_should_run_clang_format: Mock,
+    mock_should_run_python_linters: Mock,
+    mock_subprocess_run: Mock,
+    capsys: pytest.CaptureFixture[str],
+    tmp_path: Path,
+) -> None:
+    """Test that components without test files are filtered out."""
+    mock_should_run_integration_tests.return_value = False
+    mock_should_run_clang_tidy.return_value = False
+    mock_should_run_clang_format.return_value = False
+    mock_should_run_python_linters.return_value = False
+
+    # Mock list-components.py output with 3 components
+    # wifi: has tests, sensor: has tests, airthings_ble: no tests
+    mock_result = Mock()
+    mock_result.stdout = "wifi\nsensor\nairthings_ble\n"
+    mock_subprocess_run.return_value = mock_result
+
+    # Create test directory structure
+    tests_dir = tmp_path / "tests" / "components"
+
+    # wifi has tests
+    wifi_dir = tests_dir / "wifi"
+    wifi_dir.mkdir(parents=True)
+    (wifi_dir / "test.esp32.yaml").write_text("test: config")
+
+    # sensor has tests
+    sensor_dir = tests_dir / "sensor"
+    sensor_dir.mkdir(parents=True)
+    (sensor_dir / "test.esp8266.yaml").write_text("test: config")
+
+    # airthings_ble exists but has no test files
+    airthings_dir = tests_dir / "airthings_ble"
+    airthings_dir.mkdir(parents=True)
+
+    # Mock root_path to use tmp_path
+    with (
+        patch.object(determine_jobs, "root_path", str(tmp_path)),
+        patch("sys.argv", ["determine-jobs.py"]),
+    ):
+        determine_jobs.main()
+
+    # Check output
+    captured = capsys.readouterr()
+    output = json.loads(captured.out)
+
+    # changed_components should have all components
+    assert set(output["changed_components"]) == {"wifi", "sensor", "airthings_ble"}
+    # changed_components_with_tests should only have components with test files
+    assert set(output["changed_components_with_tests"]) == {"wifi", "sensor"}
+    # component_test_count should be based on components with tests
+    assert output["component_test_count"] == 2

From 5e1848854e6590d095e13341a82af6cca5b3f997 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Sat, 11 Oct 2025 11:25:19 -1000
Subject: [PATCH 15/90] tweak for bot

---
 esphome/core/helpers.cpp | 3 +++
 script/determine-jobs.py | 2 +-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/esphome/core/helpers.cpp b/esphome/core/helpers.cpp
index 82dbeddf22..0b6c203c01 100644
--- a/esphome/core/helpers.cpp
+++ b/esphome/core/helpers.cpp
@@ -246,6 +246,9 @@ std::string make_name_with_suffix(const std::string &name, char sep, const std::
 
   // Silently truncate if needed: prioritize keeping the full suffix
   if (total_len >= MAX_NAME_WITH_SUFFIX_SIZE) {
+    // NOTE: This calculation could underflow if suffix_len >= MAX_NAME_WITH_SUFFIX_SIZE - 2,
+    // but this is safe because this helper is only called with small suffixes:
+    // MAC suffixes (6-12 bytes), ".local" (6 bytes), etc.
     name_len = MAX_NAME_WITH_SUFFIX_SIZE - suffix_len - 2;  // -2 for separator and null terminator
     total_len = name_len + 1 + suffix_len;
   }
diff --git a/script/determine-jobs.py b/script/determine-jobs.py
index a078fd8f9b..1601496877 100755
--- a/script/determine-jobs.py
+++ b/script/determine-jobs.py
@@ -244,7 +244,7 @@ def main() -> None:
         component
         for component in changed_components
         if (component_test_dir := tests_dir / component).exists()
-        and any(component_test_dir.glob("test.*.yaml"))
+        and next(component_test_dir.glob("test.*.yaml"), None) is not None
     ]
 
     # Build output

From 0c8c99dbf857faba37a4c5e11977e3745e374f08 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Sat, 11 Oct 2025 12:27:39 -1000
Subject: [PATCH 16/90] [mdns] Conditionally store services to reduce RAM usage
 by 200-464 bytes

---
 esphome/components/mdns/__init__.py        | 19 ++++++++++++++++++-
 esphome/components/mdns/mdns_component.cpp | 17 +++++++++++------
 esphome/components/mdns/mdns_component.h   |  6 +++++-
 esphome/components/mdns/mdns_esp32.cpp     |  5 +++--
 esphome/components/mdns/mdns_esp8266.cpp   |  5 +++--
 esphome/components/mdns/mdns_libretiny.cpp |  5 +++--
 esphome/components/mdns/mdns_rp2040.cpp    |  5 +++--
 esphome/components/openthread/__init__.py  |  5 ++++-
 esphome/core/defines.h                     |  1 +
 9 files changed, 51 insertions(+), 17 deletions(-)

diff --git a/esphome/components/mdns/__init__.py b/esphome/components/mdns/__init__.py
index 14e0420ef5..c6a9ee1a0c 100644
--- a/esphome/components/mdns/__init__.py
+++ b/esphome/components/mdns/__init__.py
@@ -1,6 +1,6 @@
 import esphome.codegen as cg
 from esphome.components.esp32 import add_idf_component
-from esphome.config_helpers import filter_source_files_from_platform
+from esphome.config_helpers import filter_source_files_from_platform, get_logger_level
 import esphome.config_validation as cv
 from esphome.const import (
     CONF_DISABLED,
@@ -125,6 +125,17 @@ def mdns_service(
     )
 
 
+def enable_mdns_storage():
+    """Enable persistent storage of mDNS services in the MDNSComponent.
+
+    Called by external components (like OpenThread) that need access to
+    services after setup() completes via get_services().
+
+    Public API for external components. Do not remove.
+    """
+    cg.add_define("USE_MDNS_STORE_SERVICES")
+
+
 @coroutine_with_priority(CoroPriority.NETWORK_SERVICES)
 async def to_code(config):
     if config[CONF_DISABLED] is True:
@@ -150,6 +161,8 @@ async def to_code(config):
 
     if config[CONF_SERVICES]:
         cg.add_define("USE_MDNS_EXTRA_SERVICES")
+        # Extra services need to be stored persistently
+        enable_mdns_storage()
 
     # Ensure at least 1 service (fallback service)
     cg.add_define("MDNS_SERVICE_COUNT", max(1, service_count))
@@ -171,6 +184,10 @@ async def to_code(config):
     # Ensure at least 1 to avoid zero-size array
     cg.add_define("MDNS_DYNAMIC_TXT_COUNT", max(1, dynamic_txt_count))
 
+    # Enable storage if verbose logging is enabled (for dump_config)
+    if get_logger_level() in ("VERBOSE", "VERY_VERBOSE"):
+        enable_mdns_storage()
+
     var = cg.new_Pvariable(config[CONF_ID])
     await cg.register_component(var, config)
 
diff --git a/esphome/components/mdns/mdns_component.cpp b/esphome/components/mdns/mdns_component.cpp
index 9cb664c3c3..fea3ced99f 100644
--- a/esphome/components/mdns/mdns_component.cpp
+++ b/esphome/components/mdns/mdns_component.cpp
@@ -36,7 +36,7 @@ MDNS_STATIC_CONST_CHAR(SERVICE_TCP, "_tcp");
 // Wrap build-time defines into flash storage
 MDNS_STATIC_CONST_CHAR(VALUE_VERSION, ESPHOME_VERSION);
 
-void MDNSComponent::compile_records_() {
+void MDNSComponent::compile_records_(StaticVector<MDNSService, MDNS_SERVICE_COUNT> &services) {
   this->hostname_ = App.get_name();
 
   // IMPORTANT: The #ifdef blocks below must match COMPONENTS_WITH_MDNS_SERVICES
@@ -53,7 +53,7 @@ void MDNSComponent::compile_records_() {
   MDNS_STATIC_CONST_CHAR(VALUE_BOARD, ESPHOME_BOARD);
 
   if (api::global_api_server != nullptr) {
-    auto &service = this->services_.emplace_next();
+    auto &service = services.emplace_next();
     service.service_type = MDNS_STR(SERVICE_ESPHOMELIB);
     service.proto = MDNS_STR(SERVICE_TCP);
     service.port = api::global_api_server->get_port();
@@ -146,7 +146,7 @@ void MDNSComponent::compile_records_() {
 #ifdef USE_PROMETHEUS
   MDNS_STATIC_CONST_CHAR(SERVICE_PROMETHEUS, "_prometheus-http");
 
-  auto &prom_service = this->services_.emplace_next();
+  auto &prom_service = services.emplace_next();
   prom_service.service_type = MDNS_STR(SERVICE_PROMETHEUS);
   prom_service.proto = MDNS_STR(SERVICE_TCP);
   prom_service.port = USE_WEBSERVER_PORT;
@@ -155,7 +155,7 @@ void MDNSComponent::compile_records_() {
 #ifdef USE_WEBSERVER
   MDNS_STATIC_CONST_CHAR(SERVICE_HTTP, "_http");
 
-  auto &web_service = this->services_.emplace_next();
+  auto &web_service = services.emplace_next();
   web_service.service_type = MDNS_STR(SERVICE_HTTP);
   web_service.proto = MDNS_STR(SERVICE_TCP);
   web_service.port = USE_WEBSERVER_PORT;
@@ -167,12 +167,17 @@ void MDNSComponent::compile_records_() {
 
   // Publish "http" service if not using native API or any other services
   // This is just to have *some* mDNS service so that .local resolution works
-  auto &fallback_service = this->services_.emplace_next();
+  auto &fallback_service = services.emplace_next();
   fallback_service.service_type = MDNS_STR(SERVICE_HTTP);
   fallback_service.proto = MDNS_STR(SERVICE_TCP);
   fallback_service.port = USE_WEBSERVER_PORT;
   fallback_service.txt_records.push_back({MDNS_STR(TXT_VERSION), MDNS_STR(VALUE_VERSION)});
 #endif
+
+#ifdef USE_MDNS_STORE_SERVICES
+  // Copy to member variable if storage is enabled (verbose logging, OpenThread, or extra services)
+  this->services_ = services;
+#endif
 }
 
 void MDNSComponent::dump_config() {
@@ -180,7 +185,7 @@ void MDNSComponent::dump_config() {
                 "mDNS:\n"
                 "  Hostname: %s",
                 this->hostname_.c_str());
-#if ESPHOME_LOG_LEVEL >= ESPHOME_LOG_LEVEL_VERBOSE
+#ifdef USE_MDNS_STORE_SERVICES
   ESP_LOGV(TAG, "  Services:");
   for (const auto &service : this->services_) {
     ESP_LOGV(TAG, "  - %s, %s, %d", MDNS_STR_ARG(service.service_type), MDNS_STR_ARG(service.proto),
diff --git a/esphome/components/mdns/mdns_component.h b/esphome/components/mdns/mdns_component.h
index 141e42d976..62476e9504 100644
--- a/esphome/components/mdns/mdns_component.h
+++ b/esphome/components/mdns/mdns_component.h
@@ -55,7 +55,9 @@ class MDNSComponent : public Component {
   void add_extra_service(MDNSService service) { this->services_.emplace_next() = std::move(service); }
 #endif
 
+#ifdef USE_MDNS_STORE_SERVICES
   const StaticVector<MDNSService, MDNS_SERVICE_COUNT> &get_services() const { return this->services_; }
+#endif
 
   void on_shutdown() override;
 
@@ -71,9 +73,11 @@ class MDNSComponent : public Component {
   StaticVector<std::string, MDNS_DYNAMIC_TXT_COUNT> dynamic_txt_values_;
 
  protected:
+#ifdef USE_MDNS_STORE_SERVICES
   StaticVector<MDNSService, MDNS_SERVICE_COUNT> services_{};
+#endif
   std::string hostname_;
-  void compile_records_();
+  void compile_records_(StaticVector<MDNSService, MDNS_SERVICE_COUNT> &services);
 };
 
 }  // namespace mdns
diff --git a/esphome/components/mdns/mdns_esp32.cpp b/esphome/components/mdns/mdns_esp32.cpp
index e77c0b9b05..da47be7dbc 100644
--- a/esphome/components/mdns/mdns_esp32.cpp
+++ b/esphome/components/mdns/mdns_esp32.cpp
@@ -12,7 +12,8 @@ namespace mdns {
 static const char *const TAG = "mdns";
 
 void MDNSComponent::setup() {
-  this->compile_records_();
+  StaticVector<MDNSService, MDNS_SERVICE_COUNT> services;
+  this->compile_records_(services);
 
   esp_err_t err = mdns_init();
   if (err != ESP_OK) {
@@ -24,7 +25,7 @@ void MDNSComponent::setup() {
   mdns_hostname_set(this->hostname_.c_str());
   mdns_instance_name_set(this->hostname_.c_str());
 
-  for (const auto &service : this->services_) {
+  for (const auto &service : services) {
     std::vector<mdns_txt_item_t> txt_records;
     for (const auto &record : service.txt_records) {
       mdns_txt_item_t it{};
diff --git a/esphome/components/mdns/mdns_esp8266.cpp b/esphome/components/mdns/mdns_esp8266.cpp
index f3779042ed..06503742db 100644
--- a/esphome/components/mdns/mdns_esp8266.cpp
+++ b/esphome/components/mdns/mdns_esp8266.cpp
@@ -12,11 +12,12 @@ namespace esphome {
 namespace mdns {
 
 void MDNSComponent::setup() {
-  this->compile_records_();
+  StaticVector<MDNSService, MDNS_SERVICE_COUNT> services;
+  this->compile_records_(services);
 
   MDNS.begin(this->hostname_.c_str());
 
-  for (const auto &service : this->services_) {
+  for (const auto &service : services) {
     // Strip the leading underscore from the proto and service_type. While it is
     // part of the wire protocol to have an underscore, and for example ESP-IDF
     // expects the underscore to be there, the ESP8266 implementation always adds
diff --git a/esphome/components/mdns/mdns_libretiny.cpp b/esphome/components/mdns/mdns_libretiny.cpp
index 5540bf361a..a959482ff6 100644
--- a/esphome/components/mdns/mdns_libretiny.cpp
+++ b/esphome/components/mdns/mdns_libretiny.cpp
@@ -12,11 +12,12 @@ namespace esphome {
 namespace mdns {
 
 void MDNSComponent::setup() {
-  this->compile_records_();
+  StaticVector<MDNSService, MDNS_SERVICE_COUNT> services;
+  this->compile_records_(services);
 
   MDNS.begin(this->hostname_.c_str());
 
-  for (const auto &service : this->services_) {
+  for (const auto &service : services) {
     // Strip the leading underscore from the proto and service_type. While it is
     // part of the wire protocol to have an underscore, and for example ESP-IDF
     // expects the underscore to be there, the ESP8266 implementation always adds
diff --git a/esphome/components/mdns/mdns_rp2040.cpp b/esphome/components/mdns/mdns_rp2040.cpp
index 5ad006f5d4..9dfb05bda9 100644
--- a/esphome/components/mdns/mdns_rp2040.cpp
+++ b/esphome/components/mdns/mdns_rp2040.cpp
@@ -12,11 +12,12 @@ namespace esphome {
 namespace mdns {
 
 void MDNSComponent::setup() {
-  this->compile_records_();
+  StaticVector<MDNSService, MDNS_SERVICE_COUNT> services;
+  this->compile_records_(services);
 
   MDNS.begin(this->hostname_.c_str());
 
-  for (const auto &service : this->services_) {
+  for (const auto &service : services) {
     // Strip the leading underscore from the proto and service_type. While it is
     // part of the wire protocol to have an underscore, and for example ESP-IDF
     // expects the underscore to be there, the ESP8266 implementation always adds
diff --git a/esphome/components/openthread/__init__.py b/esphome/components/openthread/__init__.py
index 2f085ebaae..3fac497c3d 100644
--- a/esphome/components/openthread/__init__.py
+++ b/esphome/components/openthread/__init__.py
@@ -5,7 +5,7 @@ from esphome.components.esp32 import (
     add_idf_sdkconfig_option,
     only_on_variant,
 )
-from esphome.components.mdns import MDNSComponent
+from esphome.components.mdns import MDNSComponent, enable_mdns_storage
 import esphome.config_validation as cv
 from esphome.const import CONF_CHANNEL, CONF_ENABLE_IPV6, CONF_ID
 import esphome.final_validate as fv
@@ -141,6 +141,9 @@ FINAL_VALIDATE_SCHEMA = _final_validate
 async def to_code(config):
     cg.add_define("USE_OPENTHREAD")
 
+    # OpenThread SRP needs access to mDNS services after setup
+    enable_mdns_storage()
+
     ot = cg.new_Pvariable(config[CONF_ID])
     await cg.register_component(ot, config)
 
diff --git a/esphome/core/defines.h b/esphome/core/defines.h
index 955d0f987c..aa2c95306a 100644
--- a/esphome/core/defines.h
+++ b/esphome/core/defines.h
@@ -83,6 +83,7 @@
 #define USE_LVGL_TILEVIEW
 #define USE_LVGL_TOUCHSCREEN
 #define USE_MDNS
+#define USE_MDNS_STORE_SERVICES
 #define MDNS_SERVICE_COUNT 3
 #define MDNS_DYNAMIC_TXT_COUNT 3
 #define USE_MEDIA_PLAYER

From 0975dbfb011e18f44f2368d7fc9b0a47908484a3 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Sat, 11 Oct 2025 12:38:12 -1000
Subject: [PATCH 17/90] cleanup

---
 esphome/components/mdns/mdns_host.cpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/esphome/components/mdns/mdns_host.cpp b/esphome/components/mdns/mdns_host.cpp
index 78767ed136..f645d8d068 100644
--- a/esphome/components/mdns/mdns_host.cpp
+++ b/esphome/components/mdns/mdns_host.cpp
@@ -9,7 +9,9 @@
 namespace esphome {
 namespace mdns {
 
-void MDNSComponent::setup() { this->compile_records_(); }
+void MDNSComponent::setup() {
+  // Host platform doesn't have actual mDNS implementation
+}
 
 void MDNSComponent::on_shutdown() {}
 

From ff6191cfd4c5128f073f7e339fa749c08c96e00b Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Sat, 11 Oct 2025 12:55:03 -1000
Subject: [PATCH 18/90] [esp32_improv] Fix state not transitioning to
 PROVISIONED when WiFi configured via captive portal

---
 .../esp32_improv/esp32_improv_component.cpp   | 53 ++++++++++++-------
 .../esp32_improv/esp32_improv_component.h     |  1 +
 2 files changed, 35 insertions(+), 19 deletions(-)

diff --git a/esphome/components/esp32_improv/esp32_improv_component.cpp b/esphome/components/esp32_improv/esp32_improv_component.cpp
index f773083890..ed709da89c 100644
--- a/esphome/components/esp32_improv/esp32_improv_component.cpp
+++ b/esphome/components/esp32_improv/esp32_improv_component.cpp
@@ -40,6 +40,9 @@ void ESP32ImprovComponent::setup() {
 #endif
   global_ble_server->on_disconnect([this](uint16_t conn_id) { this->set_error_(improv::ERROR_NONE); });
 
+  // Listen for WiFi connections to detect when provisioning happens via captive portal or other means
+  wifi::global_wifi_component->get_connect_trigger()->add_callback([this]() { this->on_wifi_connected_(); });
+
   // Start with loop disabled - will be enabled by start() when needed
   this->disable_loop();
 }
@@ -161,25 +164,7 @@ void ESP32ImprovComponent::loop() {
     case improv::STATE_PROVISIONING: {
       this->set_status_indicator_state_((now % 200) < 100);
       if (wifi::global_wifi_component->is_connected()) {
-        wifi::global_wifi_component->save_wifi_sta(this->connecting_sta_.get_ssid(),
-                                                   this->connecting_sta_.get_password());
-        this->connecting_sta_ = {};
-        this->cancel_timeout("wifi-connect-timeout");
-        this->set_state_(improv::STATE_PROVISIONED);
-
-        std::vector<std::string> urls = {ESPHOME_MY_LINK};
-#ifdef USE_WEBSERVER
-        for (auto &ip : wifi::global_wifi_component->wifi_sta_ip_addresses()) {
-          if (ip.is_ip4()) {
-            std::string webserver_url = "http://" + ip.str() + ":" + to_string(USE_WEBSERVER_PORT);
-            urls.push_back(webserver_url);
-            break;
-          }
-        }
-#endif
-        std::vector<uint8_t> data = improv::build_rpc_response(improv::WIFI_SETTINGS, urls);
-        this->send_response_(data);
-        this->stop();
+        this->on_wifi_connected_();
       }
       break;
     }
@@ -392,6 +377,36 @@ void ESP32ImprovComponent::on_wifi_connect_timeout_() {
   wifi::global_wifi_component->clear_sta();
 }
 
+void ESP32ImprovComponent::on_wifi_connected_() {
+  // Handle WiFi connection, whether from Improv provisioning or external (e.g., captive portal)
+  if (this->state_ == improv::STATE_PROVISIONING) {
+    // WiFi provisioned via Improv - save credentials and send response
+    wifi::global_wifi_component->save_wifi_sta(this->connecting_sta_.get_ssid(), this->connecting_sta_.get_password());
+    this->connecting_sta_ = {};
+    this->cancel_timeout("wifi-connect-timeout");
+
+    std::vector<std::string> urls = {ESPHOME_MY_LINK};
+#ifdef USE_WEBSERVER
+    for (auto &ip : wifi::global_wifi_component->wifi_sta_ip_addresses()) {
+      if (ip.is_ip4()) {
+        std::string webserver_url = "http://" + ip.str() + ":" + to_string(USE_WEBSERVER_PORT);
+        urls.push_back(webserver_url);
+        break;
+      }
+    }
+#endif
+    std::vector<uint8_t> data = improv::build_rpc_response(improv::WIFI_SETTINGS, urls);
+    this->send_response_(data);
+  } else if (this->is_active() && this->state_ != improv::STATE_PROVISIONED) {
+    // WiFi provisioned externally (e.g., captive portal) - just transition to provisioned
+    ESP_LOGD(TAG, "WiFi provisioned externally, transitioning to provisioned state");
+  }
+
+  // Common actions for both cases
+  this->set_state_(improv::STATE_PROVISIONED);
+  this->stop();
+}
+
 void ESP32ImprovComponent::advertise_service_data_() {
   uint8_t service_data[IMPROV_SERVICE_DATA_SIZE] = {};
   service_data[0] = IMPROV_PROTOCOL_ID_1;  // PR
diff --git a/esphome/components/esp32_improv/esp32_improv_component.h b/esphome/components/esp32_improv/esp32_improv_component.h
index eb07e09dce..39c3483b2a 100644
--- a/esphome/components/esp32_improv/esp32_improv_component.h
+++ b/esphome/components/esp32_improv/esp32_improv_component.h
@@ -111,6 +111,7 @@ class ESP32ImprovComponent : public Component {
   void send_response_(std::vector<uint8_t> &response);
   void process_incoming_data_();
   void on_wifi_connect_timeout_();
+  void on_wifi_connected_();
   bool check_identify_();
   void advertise_service_data_();
 #if ESPHOME_LOG_LEVEL >= ESPHOME_LOG_LEVEL_DEBUG

From a193d5b40e3518f79ae6a246bd9bad43537b634d Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Sat, 11 Oct 2025 12:56:28 -1000
Subject: [PATCH 19/90] [esp32_improv] Fix state not transitioning to
 PROVISIONED when WiFi configured via captive portal

---
 esphome/components/esp32_improv/esp32_improv_component.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/esphome/components/esp32_improv/esp32_improv_component.cpp b/esphome/components/esp32_improv/esp32_improv_component.cpp
index ed709da89c..5060a0759a 100644
--- a/esphome/components/esp32_improv/esp32_improv_component.cpp
+++ b/esphome/components/esp32_improv/esp32_improv_component.cpp
@@ -399,7 +399,7 @@ void ESP32ImprovComponent::on_wifi_connected_() {
     this->send_response_(data);
   } else if (this->is_active() && this->state_ != improv::STATE_PROVISIONED) {
     // WiFi provisioned externally (e.g., captive portal) - just transition to provisioned
-    ESP_LOGD(TAG, "WiFi provisioned externally, transitioning to provisioned state");
+    ESP_LOGD(TAG, "WiFi provisioned externally");
   }
 
   // Common actions for both cases

From c63902781b891f6434a4be3f2ac7a24f7d997b40 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Sat, 11 Oct 2025 12:57:13 -1000
Subject: [PATCH 20/90] [esp32_improv] Fix state not transitioning to
 PROVISIONED when WiFi configured via captive portal

---
 esphome/components/esp32_improv/esp32_improv_component.cpp | 1 -
 1 file changed, 1 deletion(-)

diff --git a/esphome/components/esp32_improv/esp32_improv_component.cpp b/esphome/components/esp32_improv/esp32_improv_component.cpp
index 5060a0759a..49ec5e8ab9 100644
--- a/esphome/components/esp32_improv/esp32_improv_component.cpp
+++ b/esphome/components/esp32_improv/esp32_improv_component.cpp
@@ -402,7 +402,6 @@ void ESP32ImprovComponent::on_wifi_connected_() {
     ESP_LOGD(TAG, "WiFi provisioned externally");
   }
 
-  // Common actions for both cases
   this->set_state_(improv::STATE_PROVISIONED);
   this->stop();
 }

From 5a0184cb35ef5e1b198ebbe2784abf2aad7abce4 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Sat, 11 Oct 2025 13:01:19 -1000
Subject: [PATCH 21/90] [esp32_improv] Fix state not transitioning to
 PROVISIONED when WiFi configured via captive portal

---
 esphome/components/esp32_improv/esp32_improv_component.cpp | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/esphome/components/esp32_improv/esp32_improv_component.cpp b/esphome/components/esp32_improv/esp32_improv_component.cpp
index 49ec5e8ab9..5c32f82abb 100644
--- a/esphome/components/esp32_improv/esp32_improv_component.cpp
+++ b/esphome/components/esp32_improv/esp32_improv_component.cpp
@@ -163,9 +163,6 @@ void ESP32ImprovComponent::loop() {
     }
     case improv::STATE_PROVISIONING: {
       this->set_status_indicator_state_((now % 200) < 100);
-      if (wifi::global_wifi_component->is_connected()) {
-        this->on_wifi_connected_();
-      }
       break;
     }
     case improv::STATE_PROVISIONED: {

From 678a93cc56edca3efc4fc7add5e50f42463260b7 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Sat, 11 Oct 2025 13:08:10 -1000
Subject: [PATCH 22/90] fix

---
 .../esp32_improv/esp32_improv_component.cpp          | 12 +++++++++---
 .../components/esp32_improv/esp32_improv_component.h |  1 +
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/esphome/components/esp32_improv/esp32_improv_component.cpp b/esphome/components/esp32_improv/esp32_improv_component.cpp
index 5c32f82abb..b3258aedac 100644
--- a/esphome/components/esp32_improv/esp32_improv_component.cpp
+++ b/esphome/components/esp32_improv/esp32_improv_component.cpp
@@ -40,9 +40,6 @@ void ESP32ImprovComponent::setup() {
 #endif
   global_ble_server->on_disconnect([this](uint16_t conn_id) { this->set_error_(improv::ERROR_NONE); });
 
-  // Listen for WiFi connections to detect when provisioning happens via captive portal or other means
-  wifi::global_wifi_component->get_connect_trigger()->add_callback([this]() { this->on_wifi_connected_(); });
-
   // Start with loop disabled - will be enabled by start() when needed
   this->disable_loop();
 }
@@ -146,6 +143,7 @@ void ESP32ImprovComponent::loop() {
 #else
       this->set_state_(improv::STATE_AUTHORIZED);
 #endif
+      this->check_wifi_connection_();
       break;
     }
     case improv::STATE_AUTHORIZED: {
@@ -159,10 +157,12 @@ void ESP32ImprovComponent::loop() {
       if (!this->check_identify_()) {
         this->set_status_indicator_state_((now % 1000) < 500);
       }
+      this->check_wifi_connection_();
       break;
     }
     case improv::STATE_PROVISIONING: {
       this->set_status_indicator_state_((now % 200) < 100);
+      this->check_wifi_connection_();
       break;
     }
     case improv::STATE_PROVISIONED: {
@@ -374,6 +374,12 @@ void ESP32ImprovComponent::on_wifi_connect_timeout_() {
   wifi::global_wifi_component->clear_sta();
 }
 
+void ESP32ImprovComponent::check_wifi_connection_() {
+  if (wifi::global_wifi_component->is_connected()) {
+    this->on_wifi_connected_();
+  }
+}
+
 void ESP32ImprovComponent::on_wifi_connected_() {
   // Handle WiFi connection, whether from Improv provisioning or external (e.g., captive portal)
   if (this->state_ == improv::STATE_PROVISIONING) {
diff --git a/esphome/components/esp32_improv/esp32_improv_component.h b/esphome/components/esp32_improv/esp32_improv_component.h
index 39c3483b2a..da670f54bc 100644
--- a/esphome/components/esp32_improv/esp32_improv_component.h
+++ b/esphome/components/esp32_improv/esp32_improv_component.h
@@ -112,6 +112,7 @@ class ESP32ImprovComponent : public Component {
   void process_incoming_data_();
   void on_wifi_connect_timeout_();
   void on_wifi_connected_();
+  void check_wifi_connection_();
   bool check_identify_();
   void advertise_service_data_();
 #if ESPHOME_LOG_LEVEL >= ESPHOME_LOG_LEVEL_DEBUG

From 3758b4c8015406e06d367c3afa8067715d7fa422 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Sat, 11 Oct 2025 13:45:22 -1000
Subject: [PATCH 23/90] preen

---
 .../components/esp32_improv/esp32_improv_component.cpp   | 9 ++-------
 esphome/components/esp32_improv/esp32_improv_component.h | 1 -
 2 files changed, 2 insertions(+), 8 deletions(-)

diff --git a/esphome/components/esp32_improv/esp32_improv_component.cpp b/esphome/components/esp32_improv/esp32_improv_component.cpp
index b3258aedac..d83caf931b 100644
--- a/esphome/components/esp32_improv/esp32_improv_component.cpp
+++ b/esphome/components/esp32_improv/esp32_improv_component.cpp
@@ -375,15 +375,11 @@ void ESP32ImprovComponent::on_wifi_connect_timeout_() {
 }
 
 void ESP32ImprovComponent::check_wifi_connection_() {
-  if (wifi::global_wifi_component->is_connected()) {
-    this->on_wifi_connected_();
+  if (!wifi::global_wifi_component->is_connected()) {
+    return;
   }
-}
 
-void ESP32ImprovComponent::on_wifi_connected_() {
-  // Handle WiFi connection, whether from Improv provisioning or external (e.g., captive portal)
   if (this->state_ == improv::STATE_PROVISIONING) {
-    // WiFi provisioned via Improv - save credentials and send response
     wifi::global_wifi_component->save_wifi_sta(this->connecting_sta_.get_ssid(), this->connecting_sta_.get_password());
     this->connecting_sta_ = {};
     this->cancel_timeout("wifi-connect-timeout");
@@ -401,7 +397,6 @@ void ESP32ImprovComponent::on_wifi_connected_() {
     std::vector<uint8_t> data = improv::build_rpc_response(improv::WIFI_SETTINGS, urls);
     this->send_response_(data);
   } else if (this->is_active() && this->state_ != improv::STATE_PROVISIONED) {
-    // WiFi provisioned externally (e.g., captive portal) - just transition to provisioned
     ESP_LOGD(TAG, "WiFi provisioned externally");
   }
 
diff --git a/esphome/components/esp32_improv/esp32_improv_component.h b/esphome/components/esp32_improv/esp32_improv_component.h
index da670f54bc..6782430ffe 100644
--- a/esphome/components/esp32_improv/esp32_improv_component.h
+++ b/esphome/components/esp32_improv/esp32_improv_component.h
@@ -111,7 +111,6 @@ class ESP32ImprovComponent : public Component {
   void send_response_(std::vector<uint8_t> &response);
   void process_incoming_data_();
   void on_wifi_connect_timeout_();
-  void on_wifi_connected_();
   void check_wifi_connection_();
   bool check_identify_();
   void advertise_service_data_();

From 9f20c48a24e4adbada8c7106c8700da433cb59e3 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Sat, 11 Oct 2025 15:23:51 -1000
Subject: [PATCH 24/90] adjust

---
 esphome/components/esp32_ble/ble.cpp               |  6 +++++-
 esphome/components/ethernet/ethernet_component.cpp |  4 +++-
 esphome/components/mqtt/mqtt_client.cpp            |  3 ++-
 esphome/components/wifi/wifi_component.cpp         |  4 +++-
 esphome/core/application.h                         | 10 +++++++---
 esphome/core/helpers.cpp                           | 11 ++++++++---
 esphome/core/helpers.h                             |  5 +++--
 7 files changed, 31 insertions(+), 12 deletions(-)

diff --git a/esphome/components/esp32_ble/ble.cpp b/esphome/components/esp32_ble/ble.cpp
index e37b45fe71..7072a485a1 100644
--- a/esphome/components/esp32_ble/ble.cpp
+++ b/esphome/components/esp32_ble/ble.cpp
@@ -213,7 +213,11 @@ bool ESP32BLE::ble_setup_() {
   if (this->name_.has_value()) {
     name = this->name_.value();
     if (App.is_name_add_mac_suffix_enabled()) {
-      name = make_name_with_suffix(name, '-', get_mac_address().substr(6));
+      // MAC address suffix length (last 6 characters of 12-char MAC address string)
+      constexpr size_t MAC_ADDRESS_SUFFIX_LEN = 6;
+      const std::string mac_addr = get_mac_address();
+      const char *mac_suffix_ptr = mac_addr.c_str() + MAC_ADDRESS_SUFFIX_LEN;
+      name = make_name_with_suffix(name, '-', mac_suffix_ptr, MAC_ADDRESS_SUFFIX_LEN);
     }
   } else {
     name = App.get_name();
diff --git a/esphome/components/ethernet/ethernet_component.cpp b/esphome/components/ethernet/ethernet_component.cpp
index 5f28d6db25..8257e37b52 100644
--- a/esphome/components/ethernet/ethernet_component.cpp
+++ b/esphome/components/ethernet/ethernet_component.cpp
@@ -691,7 +691,9 @@ void EthernetComponent::set_manual_ip(const ManualIP &manual_ip) { this->manual_
 
 std::string EthernetComponent::get_use_address() const {
   if (this->use_address_.empty()) {
-    return make_name_with_suffix(App.get_name(), '.', "local");
+    // ".local" suffix length for mDNS hostnames
+    constexpr size_t MDNS_LOCAL_SUFFIX_LEN = 5;
+    return make_name_with_suffix(App.get_name(), '.', "local", MDNS_LOCAL_SUFFIX_LEN);
   }
   return this->use_address_;
 }
diff --git a/esphome/components/mqtt/mqtt_client.cpp b/esphome/components/mqtt/mqtt_client.cpp
index 3642ddb38e..16f54ab8a0 100644
--- a/esphome/components/mqtt/mqtt_client.cpp
+++ b/esphome/components/mqtt/mqtt_client.cpp
@@ -29,7 +29,8 @@ static const char *const TAG = "mqtt";
 
 MQTTClientComponent::MQTTClientComponent() {
   global_mqtt_client = this;
-  this->credentials_.client_id = make_name_with_suffix(App.get_name(), '-', get_mac_address());
+  const std::string mac_addr = get_mac_address();
+  this->credentials_.client_id = make_name_with_suffix(App.get_name(), '-', mac_addr.c_str(), mac_addr.size());
 }
 
 // Connection
diff --git a/esphome/components/wifi/wifi_component.cpp b/esphome/components/wifi/wifi_component.cpp
index ec8687e927..db9b1d43fa 100644
--- a/esphome/components/wifi/wifi_component.cpp
+++ b/esphome/components/wifi/wifi_component.cpp
@@ -267,7 +267,9 @@ network::IPAddress WiFiComponent::get_dns_address(int num) {
 }
 std::string WiFiComponent::get_use_address() const {
   if (this->use_address_.empty()) {
-    return make_name_with_suffix(App.get_name(), '.', "local");
+    // ".local" suffix length for mDNS hostnames
+    constexpr size_t MDNS_LOCAL_SUFFIX_LEN = 5;
+    return make_name_with_suffix(App.get_name(), '.', "local", MDNS_LOCAL_SUFFIX_LEN);
   }
   return this->use_address_;
 }
diff --git a/esphome/core/application.h b/esphome/core/application.h
index 47e902a191..646c2376bb 100644
--- a/esphome/core/application.h
+++ b/esphome/core/application.h
@@ -102,10 +102,14 @@ class Application {
     arch_init();
     this->name_add_mac_suffix_ = name_add_mac_suffix;
     if (name_add_mac_suffix) {
-      const std::string mac_suffix = get_mac_address().substr(6);
-      this->name_ = make_name_with_suffix(name, '-', mac_suffix);
+      // MAC address suffix length (last 6 characters of 12-char MAC address string)
+      constexpr size_t MAC_ADDRESS_SUFFIX_LEN = 6;
+      const std::string mac_addr = get_mac_address();
+      // Use pointer + offset to avoid substr() allocation
+      const char *mac_suffix_ptr = mac_addr.c_str() + MAC_ADDRESS_SUFFIX_LEN;
+      this->name_ = make_name_with_suffix(name, '-', mac_suffix_ptr, MAC_ADDRESS_SUFFIX_LEN);
       if (!friendly_name.empty()) {
-        this->friendly_name_ = make_name_with_suffix(friendly_name, ' ', mac_suffix);
+        this->friendly_name_ = make_name_with_suffix(friendly_name, ' ', mac_suffix_ptr, MAC_ADDRESS_SUFFIX_LEN);
       }
     } else {
       this->name_ = name;
diff --git a/esphome/core/helpers.cpp b/esphome/core/helpers.cpp
index 0b6c203c01..cabd9ffd16 100644
--- a/esphome/core/helpers.cpp
+++ b/esphome/core/helpers.cpp
@@ -237,11 +237,16 @@ std::string str_sprintf(const char *fmt, ...) {
 
 // Maximum size for name with suffix: 120 (max friendly name) + 1 (separator) + 6 (MAC suffix) + 1 (null term)
 static constexpr size_t MAX_NAME_WITH_SUFFIX_SIZE = 128;
+// MAC address suffix length (last 6 characters of 12-char MAC address string)
+static constexpr size_t MAC_ADDRESS_SUFFIX_LEN = 6;
+// Full MAC address string length (lowercase hex without separators)
+static constexpr size_t MAC_ADDRESS_LEN = 12;
+// ".local" suffix length for mDNS hostnames
+static constexpr size_t MDNS_LOCAL_SUFFIX_LEN = 5;
 
-std::string make_name_with_suffix(const std::string &name, char sep, const std::string &suffix) {
+std::string make_name_with_suffix(const std::string &name, char sep, const char *suffix_ptr, size_t suffix_len) {
   char buffer[MAX_NAME_WITH_SUFFIX_SIZE];
   size_t name_len = name.size();
-  size_t suffix_len = suffix.size();
   size_t total_len = name_len + 1 + suffix_len;
 
   // Silently truncate if needed: prioritize keeping the full suffix
@@ -255,7 +260,7 @@ std::string make_name_with_suffix(const std::string &name, char sep, const std::
 
   memcpy(buffer, name.c_str(), name_len);
   buffer[name_len] = sep;
-  memcpy(buffer + name_len + 1, suffix.c_str(), suffix_len);
+  memcpy(buffer + name_len + 1, suffix_ptr, suffix_len);
   buffer[total_len] = '\0';
   return std::string(buffer, total_len);
 }
diff --git a/esphome/core/helpers.h b/esphome/core/helpers.h
index f64c14aa85..adce18408e 100644
--- a/esphome/core/helpers.h
+++ b/esphome/core/helpers.h
@@ -311,9 +311,10 @@ std::string __attribute__((format(printf, 1, 2))) str_sprintf(const char *fmt, .
 /// Maximum name length supported is 120 characters for friendly names.
 /// @param name The base name string
 /// @param sep The separator character (e.g., '-', ' ', or '.')
-/// @param suffix The suffix to append (e.g., MAC address suffix or ".local")
+/// @param suffix_ptr Pointer to the suffix characters
+/// @param suffix_len Length of the suffix
 /// @return The concatenated string: name + sep + suffix
-std::string make_name_with_suffix(const std::string &name, char sep, const std::string &suffix);
+std::string make_name_with_suffix(const std::string &name, char sep, const char *suffix_ptr, size_t suffix_len);
 
 ///@}
 

From 21c2c6e7825190d93eb3ea3aba6d529fcea40090 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Sat, 11 Oct 2025 15:33:19 -1000
Subject: [PATCH 25/90] Update esphome/config_validation.py

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
---
 esphome/config_validation.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/esphome/config_validation.py b/esphome/config_validation.py
index 2746f574ba..ebfedf2017 100644
--- a/esphome/config_validation.py
+++ b/esphome/config_validation.py
@@ -1200,7 +1200,7 @@ def hostname(value):
     Maximum length is 63 characters per RFC 1035.
 
     Note: If this limit is changed, update MAX_NAME_WITH_SUFFIX_SIZE in
-    esphome/core/application.h to accommodate the new maximum length.
+    esphome/core/helpers.cpp to accommodate the new maximum length.
     """
     value = string(value)
     if re.match(r"^[a-z0-9-]{1,63}$", value, re.IGNORECASE) is not None:

From 5fe319fcc56217c38e47b206b00784691bba1b79 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Sat, 11 Oct 2025 15:33:22 -1000
Subject: [PATCH 26/90] preen

---
 esphome/core/helpers.cpp | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/esphome/core/helpers.cpp b/esphome/core/helpers.cpp
index cabd9ffd16..2d8122699b 100644
--- a/esphome/core/helpers.cpp
+++ b/esphome/core/helpers.cpp
@@ -237,12 +237,6 @@ std::string str_sprintf(const char *fmt, ...) {
 
 // Maximum size for name with suffix: 120 (max friendly name) + 1 (separator) + 6 (MAC suffix) + 1 (null term)
 static constexpr size_t MAX_NAME_WITH_SUFFIX_SIZE = 128;
-// MAC address suffix length (last 6 characters of 12-char MAC address string)
-static constexpr size_t MAC_ADDRESS_SUFFIX_LEN = 6;
-// Full MAC address string length (lowercase hex without separators)
-static constexpr size_t MAC_ADDRESS_LEN = 12;
-// ".local" suffix length for mDNS hostnames
-static constexpr size_t MDNS_LOCAL_SUFFIX_LEN = 5;
 
 std::string make_name_with_suffix(const std::string &name, char sep, const char *suffix_ptr, size_t suffix_len) {
   char buffer[MAX_NAME_WITH_SUFFIX_SIZE];

From e69013317d8c6f64e1d7bb5677e353d68730272c Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Sat, 11 Oct 2025 15:33:46 -1000
Subject: [PATCH 27/90] Update esphome/core/helpers.cpp

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
---
 esphome/core/helpers.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/esphome/core/helpers.cpp b/esphome/core/helpers.cpp
index 2d8122699b..fb8b220b2f 100644
--- a/esphome/core/helpers.cpp
+++ b/esphome/core/helpers.cpp
@@ -247,7 +247,7 @@ std::string make_name_with_suffix(const std::string &name, char sep, const char
   if (total_len >= MAX_NAME_WITH_SUFFIX_SIZE) {
     // NOTE: This calculation could underflow if suffix_len >= MAX_NAME_WITH_SUFFIX_SIZE - 2,
     // but this is safe because this helper is only called with small suffixes:
-    // MAC suffixes (6-12 bytes), ".local" (6 bytes), etc.
+    // MAC suffixes (6-12 bytes), ".local" (5 bytes), etc.
     name_len = MAX_NAME_WITH_SUFFIX_SIZE - suffix_len - 2;  // -2 for separator and null terminator
     total_len = name_len + 1 + suffix_len;
   }

From 153f01ef773c31bedf0350bd2440247906fea120 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Sat, 11 Oct 2025 15:34:15 -1000
Subject: [PATCH 28/90] preen

---
 script/determine-jobs.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/script/determine-jobs.py b/script/determine-jobs.py
index 1601496877..a078fd8f9b 100755
--- a/script/determine-jobs.py
+++ b/script/determine-jobs.py
@@ -244,7 +244,7 @@ def main() -> None:
         component
         for component in changed_components
         if (component_test_dir := tests_dir / component).exists()
-        and next(component_test_dir.glob("test.*.yaml"), None) is not None
+        and any(component_test_dir.glob("test.*.yaml"))
     ]
 
     # Build output

From b0c20d7adb8df3cf61d5292c09233bc295af3b4d Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Sat, 11 Oct 2025 16:54:11 -1000
Subject: [PATCH 29/90] [core] Optimize looping_components_ with FixedVector to
 save flash

---
 esphome/core/application.cpp |  4 ++--
 esphome/core/application.h   |  2 +-
 esphome/core/helpers.h       | 44 ++++++++++++++++++++++++++++++++++++
 3 files changed, 47 insertions(+), 3 deletions(-)

diff --git a/esphome/core/application.cpp b/esphome/core/application.cpp
index 1be193bb7e..c745aa0ae5 100644
--- a/esphome/core/application.cpp
+++ b/esphome/core/application.cpp
@@ -340,8 +340,8 @@ void Application::calculate_looping_components_() {
     }
   }
 
-  // Pre-reserve vector to avoid reallocations
-  this->looping_components_.reserve(total_looping);
+  // Initialize FixedVector with exact size - no reallocation possible
+  this->looping_components_.init(total_looping);
 
   // Add all components with loop override that aren't already LOOP_DONE
   // Some components (like logger) may call disable_loop() during initialization
diff --git a/esphome/core/application.h b/esphome/core/application.h
index 1f22499051..b0f9c23191 100644
--- a/esphome/core/application.h
+++ b/esphome/core/application.h
@@ -472,7 +472,7 @@ class Application {
   // - When a component is enabled, it's swapped with the first inactive component
   //   and active_end_ is incremented
   // - This eliminates branch mispredictions from flag checking in the hot loop
-  std::vector<Component *> looping_components_{};
+  FixedVector<Component *> looping_components_{};
 #ifdef USE_SOCKET_SELECT_SUPPORT
   std::vector<int> socket_fds_;  // Vector of all monitored socket file descriptors
 #endif
diff --git a/esphome/core/helpers.h b/esphome/core/helpers.h
index e06f2d15ef..864fd92ffc 100644
--- a/esphome/core/helpers.h
+++ b/esphome/core/helpers.h
@@ -159,6 +159,50 @@ template<typename T, size_t N> class StaticVector {
   const_reverse_iterator rend() const { return const_reverse_iterator(begin()); }
 };
 
+/// Fixed-capacity vector - allocates once at runtime, never reallocates
+/// This avoids std::vector template overhead (_M_realloc_insert, _M_default_append)
+/// when size is known at initialization but not at compile time
+template<typename T> class FixedVector {
+ private:
+  T *data_{nullptr};
+  size_t size_{0};
+  size_t capacity_{0};
+
+ public:
+  FixedVector() = default;
+
+  ~FixedVector() {
+    if (data_ != nullptr) {
+      delete[] data_;
+    }
+  }
+
+  // Disable copy to avoid accidental copies
+  FixedVector(const FixedVector &) = delete;
+  FixedVector &operator=(const FixedVector &) = delete;
+
+  // Allocate capacity - can only be called once on empty vector
+  void init(size_t n) {
+    if (data_ == nullptr && n > 0) {
+      data_ = new T[n];
+      capacity_ = n;
+      size_ = 0;
+    }
+  }
+
+  // Add element (no reallocation - must have initialized capacity)
+  void push_back(const T &value) {
+    if (size_ < capacity_) {
+      data_[size_++] = value;
+    }
+  }
+
+  size_t size() const { return size_; }
+
+  T &operator[](size_t i) { return data_[i]; }
+  const T &operator[](size_t i) const { return data_[i]; }
+};
+
 ///@}
 
 /// @name Mathematics

From fdc9ea285dcd57de91f764c2802dd9cc8f7c3e8b Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Sat, 11 Oct 2025 17:30:30 -1000
Subject: [PATCH 30/90] [http_request] Pass parameters by const reference to
 reduce flash usage

---
 esphome/components/http_request/http_request.h           | 4 ++--
 esphome/components/http_request/http_request_arduino.cpp | 5 +++--
 esphome/components/http_request/http_request_arduino.h   | 4 ++--
 esphome/components/http_request/http_request_host.cpp    | 5 +++--
 esphome/components/http_request/http_request_host.h      | 4 ++--
 esphome/components/http_request/http_request_idf.cpp     | 5 +++--
 esphome/components/http_request/http_request_idf.h       | 4 ++--
 7 files changed, 17 insertions(+), 14 deletions(-)

diff --git a/esphome/components/http_request/http_request.h b/esphome/components/http_request/http_request.h
index 95515f731a..bb14cc6f51 100644
--- a/esphome/components/http_request/http_request.h
+++ b/esphome/components/http_request/http_request.h
@@ -167,8 +167,8 @@ class HttpRequestComponent : public Component {
   }
 
  protected:
-  virtual std::shared_ptr<HttpContainer> perform(std::string url, std::string method, std::string body,
-                                                 std::list<Header> request_headers,
+  virtual std::shared_ptr<HttpContainer> perform(const std::string &url, const std::string &method,
+                                                 const std::string &body, const std::list<Header> &request_headers,
                                                  std::set<std::string> collect_headers) = 0;
   const char *useragent_{nullptr};
   bool follow_redirects_{};
diff --git a/esphome/components/http_request/http_request_arduino.cpp b/esphome/components/http_request/http_request_arduino.cpp
index c009b33c2d..dfdbbd3fab 100644
--- a/esphome/components/http_request/http_request_arduino.cpp
+++ b/esphome/components/http_request/http_request_arduino.cpp
@@ -14,8 +14,9 @@ namespace http_request {
 
 static const char *const TAG = "http_request.arduino";
 
-std::shared_ptr<HttpContainer> HttpRequestArduino::perform(std::string url, std::string method, std::string body,
-                                                           std::list<Header> request_headers,
+std::shared_ptr<HttpContainer> HttpRequestArduino::perform(const std::string &url, const std::string &method,
+                                                           const std::string &body,
+                                                           const std::list<Header> &request_headers,
                                                            std::set<std::string> collect_headers) {
   if (!network::is_connected()) {
     this->status_momentary_error("failed", 1000);
diff --git a/esphome/components/http_request/http_request_arduino.h b/esphome/components/http_request/http_request_arduino.h
index 44744f8c78..c8208c74d8 100644
--- a/esphome/components/http_request/http_request_arduino.h
+++ b/esphome/components/http_request/http_request_arduino.h
@@ -31,8 +31,8 @@ class HttpContainerArduino : public HttpContainer {
 
 class HttpRequestArduino : public HttpRequestComponent {
  protected:
-  std::shared_ptr<HttpContainer> perform(std::string url, std::string method, std::string body,
-                                         std::list<Header> request_headers,
+  std::shared_ptr<HttpContainer> perform(const std::string &url, const std::string &method, const std::string &body,
+                                         const std::list<Header> &request_headers,
                                          std::set<std::string> collect_headers) override;
 };
 
diff --git a/esphome/components/http_request/http_request_host.cpp b/esphome/components/http_request/http_request_host.cpp
index 0b4c998a40..c20ea552b7 100644
--- a/esphome/components/http_request/http_request_host.cpp
+++ b/esphome/components/http_request/http_request_host.cpp
@@ -17,8 +17,9 @@ namespace http_request {
 
 static const char *const TAG = "http_request.host";
 
-std::shared_ptr<HttpContainer> HttpRequestHost::perform(std::string url, std::string method, std::string body,
-                                                        std::list<Header> request_headers,
+std::shared_ptr<HttpContainer> HttpRequestHost::perform(const std::string &url, const std::string &method,
+                                                        const std::string &body,
+                                                        const std::list<Header> &request_headers,
                                                         std::set<std::string> response_headers) {
   if (!network::is_connected()) {
     this->status_momentary_error("failed", 1000);
diff --git a/esphome/components/http_request/http_request_host.h b/esphome/components/http_request/http_request_host.h
index bbeed87f70..fdd72e7ea5 100644
--- a/esphome/components/http_request/http_request_host.h
+++ b/esphome/components/http_request/http_request_host.h
@@ -18,8 +18,8 @@ class HttpContainerHost : public HttpContainer {
 
 class HttpRequestHost : public HttpRequestComponent {
  public:
-  std::shared_ptr<HttpContainer> perform(std::string url, std::string method, std::string body,
-                                         std::list<Header> request_headers,
+  std::shared_ptr<HttpContainer> perform(const std::string &url, const std::string &method, const std::string &body,
+                                         const std::list<Header> &request_headers,
                                          std::set<std::string> response_headers) override;
   void set_ca_path(const char *ca_path) { this->ca_path_ = ca_path; }
 
diff --git a/esphome/components/http_request/http_request_idf.cpp b/esphome/components/http_request/http_request_idf.cpp
index 89a0891b03..a91c0bfc25 100644
--- a/esphome/components/http_request/http_request_idf.cpp
+++ b/esphome/components/http_request/http_request_idf.cpp
@@ -52,8 +52,9 @@ esp_err_t HttpRequestIDF::http_event_handler(esp_http_client_event_t *evt) {
   return ESP_OK;
 }
 
-std::shared_ptr<HttpContainer> HttpRequestIDF::perform(std::string url, std::string method, std::string body,
-                                                       std::list<Header> request_headers,
+std::shared_ptr<HttpContainer> HttpRequestIDF::perform(const std::string &url, const std::string &method,
+                                                       const std::string &body,
+                                                       const std::list<Header> &request_headers,
                                                        std::set<std::string> collect_headers) {
   if (!network::is_connected()) {
     this->status_momentary_error("failed", 1000);
diff --git a/esphome/components/http_request/http_request_idf.h b/esphome/components/http_request/http_request_idf.h
index 5c5b784853..90dee0be68 100644
--- a/esphome/components/http_request/http_request_idf.h
+++ b/esphome/components/http_request/http_request_idf.h
@@ -37,8 +37,8 @@ class HttpRequestIDF : public HttpRequestComponent {
   void set_buffer_size_tx(uint16_t buffer_size_tx) { this->buffer_size_tx_ = buffer_size_tx; }
 
  protected:
-  std::shared_ptr<HttpContainer> perform(std::string url, std::string method, std::string body,
-                                         std::list<Header> request_headers,
+  std::shared_ptr<HttpContainer> perform(const std::string &url, const std::string &method, const std::string &body,
+                                         const std::list<Header> &request_headers,
                                          std::set<std::string> collect_headers) override;
   // if zero ESP-IDF will use DEFAULT_HTTP_BUF_SIZE
   uint16_t buffer_size_rx_{};

From 2ff3e7fb2bd017dddd187065078c21126f959cbe Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Sat, 11 Oct 2025 17:34:51 -1000
Subject: [PATCH 31/90] add comments for bot

---
 esphome/core/helpers.h | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/esphome/core/helpers.h b/esphome/core/helpers.h
index 864fd92ffc..3782875dcf 100644
--- a/esphome/core/helpers.h
+++ b/esphome/core/helpers.h
@@ -190,7 +190,9 @@ template<typename T> class FixedVector {
     }
   }
 
-  // Add element (no reallocation - must have initialized capacity)
+  /// Add element without bounds checking
+  /// Caller must ensure sufficient capacity was allocated via init()
+  /// Silently ignores pushes beyond capacity to avoid runtime overhead
   void push_back(const T &value) {
     if (size_ < capacity_) {
       data_[size_++] = value;
@@ -199,6 +201,8 @@ template<typename T> class FixedVector {
 
   size_t size() const { return size_; }
 
+  /// Access element without bounds checking (matches std::vector behavior)
+  /// Caller must ensure index is valid (i < size())
   T &operator[](size_t i) { return data_[i]; }
   const T &operator[](size_t i) const { return data_[i]; }
 };

From 4c00861760ce5fd22b7ac82584ba9dd20f1e23ee Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Sat, 11 Oct 2025 17:35:31 -1000
Subject: [PATCH 32/90] add comments for bot

---
 esphome/core/helpers.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/esphome/core/helpers.h b/esphome/core/helpers.h
index 3782875dcf..b5a0a1c8ac 100644
--- a/esphome/core/helpers.h
+++ b/esphome/core/helpers.h
@@ -192,7 +192,7 @@ template<typename T> class FixedVector {
 
   /// Add element without bounds checking
   /// Caller must ensure sufficient capacity was allocated via init()
-  /// Silently ignores pushes beyond capacity to avoid runtime overhead
+  /// Silently ignores pushes beyond capacity (no exception or assertion)
   void push_back(const T &value) {
     if (size_ < capacity_) {
       data_[size_++] = value;

From 66c8c045f21be353f3e68f0056639d3fdea5fcf6 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Sat, 11 Oct 2025 21:23:02 -1000
Subject: [PATCH 33/90] [ota] Increase handshake timeout to 20s now that auth
 is non-blocking

---
 esphome/components/esphome/ota/ota_esphome.cpp | 2 +-
 esphome/espota2.py                             | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/esphome/components/esphome/ota/ota_esphome.cpp b/esphome/components/esphome/ota/ota_esphome.cpp
index b65bfc5ab8..569268ea15 100644
--- a/esphome/components/esphome/ota/ota_esphome.cpp
+++ b/esphome/components/esphome/ota/ota_esphome.cpp
@@ -29,7 +29,7 @@ namespace esphome {
 static const char *const TAG = "esphome.ota";
 static constexpr uint16_t OTA_BLOCK_SIZE = 8192;
 static constexpr size_t OTA_BUFFER_SIZE = 1024;                  // buffer size for OTA data transfer
-static constexpr uint32_t OTA_SOCKET_TIMEOUT_HANDSHAKE = 10000;  // milliseconds for initial handshake
+static constexpr uint32_t OTA_SOCKET_TIMEOUT_HANDSHAKE = 20000;  // milliseconds for initial handshake
 static constexpr uint32_t OTA_SOCKET_TIMEOUT_DATA = 90000;       // milliseconds for data transfer
 
 #ifdef USE_OTA_PASSWORD
diff --git a/esphome/espota2.py b/esphome/espota2.py
index 2712d00127..17a1da8235 100644
--- a/esphome/espota2.py
+++ b/esphome/espota2.py
@@ -410,7 +410,7 @@ def run_ota_impl_(
         af, socktype, _, _, sa = r
         _LOGGER.info("Connecting to %s port %s...", sa[0], sa[1])
         sock = socket.socket(af, socktype)
-        sock.settimeout(10.0)
+        sock.settimeout(20.0)
         try:
             sock.connect(sa)
         except OSError as err:

From 072662c395c27a36b3720f75c753956f79e0550f Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Sat, 11 Oct 2025 21:26:13 -1000
Subject: [PATCH 34/90] timeout

---
 tests/unit_tests/test_espota2.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/unit_tests/test_espota2.py b/tests/unit_tests/test_espota2.py
index bd1a6bde81..52c72291d6 100644
--- a/tests/unit_tests/test_espota2.py
+++ b/tests/unit_tests/test_espota2.py
@@ -493,7 +493,7 @@ def test_run_ota_impl_successful(
     assert result_host == "192.168.1.100"
 
     # Verify socket was configured correctly
-    mock_socket.settimeout.assert_called_with(10.0)
+    mock_socket.settimeout.assert_called_with(20.0)
     mock_socket.connect.assert_called_once_with(("192.168.1.100", 3232))
     mock_socket.close.assert_called_once()
 

From ddc7a15302b0a0d622bd2a1b78e47b3e07d3a95e Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Sat, 11 Oct 2025 22:02:59 -1000
Subject: [PATCH 35/90] [wifi] Fix missed string literal in flash on ESP8266

---
 esphome/components/wifi/wifi_component.cpp | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/esphome/components/wifi/wifi_component.cpp b/esphome/components/wifi/wifi_component.cpp
index 2e083d4c68..71ee4271ba 100644
--- a/esphome/components/wifi/wifi_component.cpp
+++ b/esphome/components/wifi/wifi_component.cpp
@@ -576,8 +576,9 @@ __attribute__((noinline)) static void log_scan_result(const WiFiScanResult &res)
   format_mac_addr_upper(bssid.data(), bssid_s);
 
   if (res.get_matches()) {
-    ESP_LOGI(TAG, "- '%s' %s" LOG_SECRET("(%s) ") "%s", res.get_ssid().c_str(), res.get_is_hidden() ? "(HIDDEN) " : "",
-             bssid_s, LOG_STR_ARG(get_signal_bars(res.get_rssi())));
+    ESP_LOGI(TAG, "- '%s' %s" LOG_SECRET("(%s) ") "%s", res.get_ssid().c_str(),
+             res.get_is_hidden() ? LOG_STR_LITERAL("(HIDDEN) ") : LOG_STR_LITERAL(""), bssid_s,
+             LOG_STR_ARG(get_signal_bars(res.get_rssi())));
     ESP_LOGD(TAG,
              "    Channel: %u\n"
              "    RSSI: %d dB",

From 2a94463ac1d3f86250efdbf6e25838ce4377ac22 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Sun, 12 Oct 2025 11:07:01 -1000
Subject: [PATCH 36/90] [esp32_ble] Replace handler vectors with StaticVector
 for 2KB memory savings

---
 esphome/components/esp32_ble/__init__.py      | 78 +++++++++++++++++++
 esphome/components/esp32_ble/ble.cpp          | 22 +++++-
 esphome/components/esp32_ble/ble.h            | 44 ++++++++---
 .../components/esp32_ble_beacon/__init__.py   |  2 +-
 .../components/esp32_ble_server/__init__.py   |  4 +-
 .../components/esp32_ble_tracker/__init__.py  |  8 +-
 esphome/core/defines.h                        |  5 ++
 7 files changed, 141 insertions(+), 22 deletions(-)

diff --git a/esphome/components/esp32_ble/__init__.py b/esphome/components/esp32_ble/__init__.py
index 1c142ca7bd..d2ce4716f4 100644
--- a/esphome/components/esp32_ble/__init__.py
+++ b/esphome/components/esp32_ble/__init__.py
@@ -1,4 +1,5 @@
 from collections.abc import Callable, MutableMapping
+from dataclasses import dataclass
 from enum import Enum
 import logging
 import re
@@ -111,6 +112,58 @@ class BTLoggers(Enum):
 _required_loggers: set[BTLoggers] = set()
 
 
+# Dataclass for handler registration counts
+@dataclass
+class HandlerCounts:
+    gap_event: int = 0
+    gap_scan_event: int = 0
+    gattc_event: int = 0
+    gatts_event: int = 0
+    ble_status_event: int = 0
+
+
+# Track handler registration counts for StaticVector sizing
+_handler_counts = HandlerCounts()
+
+
+def register_gap_event_handler(parent_var: cg.MockObj, handler_var: cg.MockObj) -> None:
+    """Register a GAP event handler and track the count."""
+    _handler_counts.gap_event += 1
+    cg.add(parent_var.register_gap_event_handler(handler_var))
+
+
+def register_gap_scan_event_handler(
+    parent_var: cg.MockObj, handler_var: cg.MockObj
+) -> None:
+    """Register a GAP scan event handler and track the count."""
+    _handler_counts.gap_scan_event += 1
+    cg.add(parent_var.register_gap_scan_event_handler(handler_var))
+
+
+def register_gattc_event_handler(
+    parent_var: cg.MockObj, handler_var: cg.MockObj
+) -> None:
+    """Register a GATTc event handler and track the count."""
+    _handler_counts.gattc_event += 1
+    cg.add(parent_var.register_gattc_event_handler(handler_var))
+
+
+def register_gatts_event_handler(
+    parent_var: cg.MockObj, handler_var: cg.MockObj
+) -> None:
+    """Register a GATTs event handler and track the count."""
+    _handler_counts.gatts_event += 1
+    cg.add(parent_var.register_gatts_event_handler(handler_var))
+
+
+def register_ble_status_event_handler(
+    parent_var: cg.MockObj, handler_var: cg.MockObj
+) -> None:
+    """Register a BLE status event handler and track the count."""
+    _handler_counts.ble_status_event += 1
+    cg.add(parent_var.register_ble_status_event_handler(handler_var))
+
+
 def register_bt_logger(*loggers: BTLoggers) -> None:
     """Register Bluetooth logger categories that a component needs.
 
@@ -368,6 +421,31 @@ def final_validation(config):
     # For newer chips (C3/S3/etc), different configs are used automatically
     add_idf_sdkconfig_option("CONFIG_BTDM_CTRL_BLE_MAX_CONN", max_connections)
 
+    # Add defines for StaticVector sizing based on handler registration counts
+    # Only define if count > 0 to avoid allocating unnecessary memory
+    if _handler_counts.gap_event > 0:
+        cg.add_define(
+            "ESPHOME_ESP32_BLE_GAP_EVENT_HANDLER_COUNT", _handler_counts.gap_event
+        )
+    if _handler_counts.gap_scan_event > 0:
+        cg.add_define(
+            "ESPHOME_ESP32_BLE_GAP_SCAN_EVENT_HANDLER_COUNT",
+            _handler_counts.gap_scan_event,
+        )
+    if _handler_counts.gattc_event > 0:
+        cg.add_define(
+            "ESPHOME_ESP32_BLE_GATTC_EVENT_HANDLER_COUNT", _handler_counts.gattc_event
+        )
+    if _handler_counts.gatts_event > 0:
+        cg.add_define(
+            "ESPHOME_ESP32_BLE_GATTS_EVENT_HANDLER_COUNT", _handler_counts.gatts_event
+        )
+    if _handler_counts.ble_status_event > 0:
+        cg.add_define(
+            "ESPHOME_ESP32_BLE_BLE_STATUS_EVENT_HANDLER_COUNT",
+            _handler_counts.ble_status_event,
+        )
+
     return config
 
 
diff --git a/esphome/components/esp32_ble/ble.cpp b/esphome/components/esp32_ble/ble.cpp
index 0c340c55cc..ca119f8836 100644
--- a/esphome/components/esp32_ble/ble.cpp
+++ b/esphome/components/esp32_ble/ble.cpp
@@ -181,6 +181,7 @@ bool ESP32BLE::ble_setup_() {
     return false;
   }
 
+#ifdef ESPHOME_ESP32_BLE_GAP_EVENT_HANDLER_COUNT
   if (!this->gap_event_handlers_.empty()) {
     err = esp_ble_gap_register_callback(ESP32BLE::gap_event_handler);
     if (err != ESP_OK) {
@@ -188,8 +189,9 @@ bool ESP32BLE::ble_setup_() {
       return false;
     }
   }
+#endif
 
-#ifdef USE_ESP32_BLE_SERVER
+#if defined(USE_ESP32_BLE_SERVER) && defined(ESPHOME_ESP32_BLE_GATTS_EVENT_HANDLER_COUNT)
   if (!this->gatts_event_handlers_.empty()) {
     err = esp_ble_gatts_register_callback(ESP32BLE::gatts_event_handler);
     if (err != ESP_OK) {
@@ -199,7 +201,7 @@ bool ESP32BLE::ble_setup_() {
   }
 #endif
 
-#ifdef USE_ESP32_BLE_CLIENT
+#if defined(USE_ESP32_BLE_CLIENT) && defined(ESPHOME_ESP32_BLE_GATTC_EVENT_HANDLER_COUNT)
   if (!this->gattc_event_handlers_.empty()) {
     err = esp_ble_gattc_register_callback(ESP32BLE::gattc_event_handler);
     if (err != ESP_OK) {
@@ -299,9 +301,11 @@ void ESP32BLE::loop() {
     case BLE_COMPONENT_STATE_DISABLE: {
       ESP_LOGD(TAG, "Disabling");
 
+#ifdef ESPHOME_ESP32_BLE_BLE_STATUS_EVENT_HANDLER_COUNT
       for (auto *ble_event_handler : this->ble_status_event_handlers_) {
         ble_event_handler->ble_before_disabled_event_handler();
       }
+#endif
 
       if (!ble_dismantle_()) {
         ESP_LOGE(TAG, "Could not be dismantled");
@@ -331,7 +335,7 @@ void ESP32BLE::loop() {
   BLEEvent *ble_event = this->ble_events_.pop();
   while (ble_event != nullptr) {
     switch (ble_event->type_) {
-#ifdef USE_ESP32_BLE_SERVER
+#if defined(USE_ESP32_BLE_SERVER) && defined(ESPHOME_ESP32_BLE_GATTS_EVENT_HANDLER_COUNT)
       case BLEEvent::GATTS: {
         esp_gatts_cb_event_t event = ble_event->event_.gatts.gatts_event;
         esp_gatt_if_t gatts_if = ble_event->event_.gatts.gatts_if;
@@ -343,7 +347,7 @@ void ESP32BLE::loop() {
         break;
       }
 #endif
-#ifdef USE_ESP32_BLE_CLIENT
+#if defined(USE_ESP32_BLE_CLIENT) && defined(ESPHOME_ESP32_BLE_GATTC_EVENT_HANDLER_COUNT)
       case BLEEvent::GATTC: {
         esp_gattc_cb_event_t event = ble_event->event_.gattc.gattc_event;
         esp_gatt_if_t gattc_if = ble_event->event_.gattc.gattc_if;
@@ -359,10 +363,12 @@ void ESP32BLE::loop() {
         esp_gap_ble_cb_event_t gap_event = ble_event->event_.gap.gap_event;
         switch (gap_event) {
           case ESP_GAP_BLE_SCAN_RESULT_EVT:
+#ifdef ESPHOME_ESP32_BLE_GAP_SCAN_EVENT_HANDLER_COUNT
             // Use the new scan event handler - no memcpy!
             for (auto *scan_handler : this->gap_scan_event_handlers_) {
               scan_handler->gap_scan_event_handler(ble_event->scan_result());
             }
+#endif
             break;
 
           // Scan complete events
@@ -374,10 +380,12 @@ void ESP32BLE::loop() {
             // This is verified at compile-time by static_assert checks in ble_event.h
             // The struct already contains our copy of the status (copied in BLEEvent constructor)
             ESP_LOGV(TAG, "gap_event_handler - %d", gap_event);
+#ifdef ESPHOME_ESP32_BLE_GAP_EVENT_HANDLER_COUNT
             for (auto *gap_handler : this->gap_event_handlers_) {
               gap_handler->gap_event_handler(
                   gap_event, reinterpret_cast<esp_ble_gap_cb_param_t *>(&ble_event->event_.gap.scan_complete));
             }
+#endif
             break;
 
           // Advertising complete events
@@ -388,19 +396,23 @@ void ESP32BLE::loop() {
           case ESP_GAP_BLE_ADV_STOP_COMPLETE_EVT:
             // All advertising complete events have the same structure with just status
             ESP_LOGV(TAG, "gap_event_handler - %d", gap_event);
+#ifdef ESPHOME_ESP32_BLE_GAP_EVENT_HANDLER_COUNT
             for (auto *gap_handler : this->gap_event_handlers_) {
               gap_handler->gap_event_handler(
                   gap_event, reinterpret_cast<esp_ble_gap_cb_param_t *>(&ble_event->event_.gap.adv_complete));
             }
+#endif
             break;
 
           // RSSI complete event
           case ESP_GAP_BLE_READ_RSSI_COMPLETE_EVT:
             ESP_LOGV(TAG, "gap_event_handler - %d", gap_event);
+#ifdef ESPHOME_ESP32_BLE_GAP_EVENT_HANDLER_COUNT
             for (auto *gap_handler : this->gap_event_handlers_) {
               gap_handler->gap_event_handler(
                   gap_event, reinterpret_cast<esp_ble_gap_cb_param_t *>(&ble_event->event_.gap.read_rssi_complete));
             }
+#endif
             break;
 
           // Security events
@@ -410,10 +422,12 @@ void ESP32BLE::loop() {
           case ESP_GAP_BLE_PASSKEY_REQ_EVT:
           case ESP_GAP_BLE_NC_REQ_EVT:
             ESP_LOGV(TAG, "gap_event_handler - %d", gap_event);
+#ifdef ESPHOME_ESP32_BLE_GAP_EVENT_HANDLER_COUNT
             for (auto *gap_handler : this->gap_event_handlers_) {
               gap_handler->gap_event_handler(
                   gap_event, reinterpret_cast<esp_ble_gap_cb_param_t *>(&ble_event->event_.gap.security));
             }
+#endif
             break;
 
           default:
diff --git a/esphome/components/esp32_ble/ble.h b/esphome/components/esp32_ble/ble.h
index 1aa3bc86ef..617047372b 100644
--- a/esphome/components/esp32_ble/ble.h
+++ b/esphome/components/esp32_ble/ble.h
@@ -125,18 +125,34 @@ class ESP32BLE : public Component {
   void advertising_register_raw_advertisement_callback(std::function<void(bool)> &&callback);
 #endif
 
-  void register_gap_event_handler(GAPEventHandler *handler) { this->gap_event_handlers_.push_back(handler); }
+  void register_gap_event_handler(GAPEventHandler *handler) {
+#ifdef ESPHOME_ESP32_BLE_GAP_EVENT_HANDLER_COUNT
+    this->gap_event_handlers_.push_back(handler);
+#endif
+  }
   void register_gap_scan_event_handler(GAPScanEventHandler *handler) {
+#ifdef ESPHOME_ESP32_BLE_GAP_SCAN_EVENT_HANDLER_COUNT
     this->gap_scan_event_handlers_.push_back(handler);
+#endif
   }
 #ifdef USE_ESP32_BLE_CLIENT
-  void register_gattc_event_handler(GATTcEventHandler *handler) { this->gattc_event_handlers_.push_back(handler); }
+  void register_gattc_event_handler(GATTcEventHandler *handler) {
+#ifdef ESPHOME_ESP32_BLE_GATTC_EVENT_HANDLER_COUNT
+    this->gattc_event_handlers_.push_back(handler);
+#endif
+  }
 #endif
 #ifdef USE_ESP32_BLE_SERVER
-  void register_gatts_event_handler(GATTsEventHandler *handler) { this->gatts_event_handlers_.push_back(handler); }
+  void register_gatts_event_handler(GATTsEventHandler *handler) {
+#ifdef ESPHOME_ESP32_BLE_GATTS_EVENT_HANDLER_COUNT
+    this->gatts_event_handlers_.push_back(handler);
+#endif
+  }
 #endif
   void register_ble_status_event_handler(BLEStatusEventHandler *handler) {
+#ifdef ESPHOME_ESP32_BLE_BLE_STATUS_EVENT_HANDLER_COUNT
     this->ble_status_event_handlers_.push_back(handler);
+#endif
   }
   void set_enable_on_boot(bool enable_on_boot) { this->enable_on_boot_ = enable_on_boot; }
 
@@ -159,16 +175,22 @@ class ESP32BLE : public Component {
  private:
   template<typename... Args> friend void enqueue_ble_event(Args... args);
 
-  // Vectors (12 bytes each on 32-bit, naturally aligned to 4 bytes)
-  std::vector<GAPEventHandler *> gap_event_handlers_;
-  std::vector<GAPScanEventHandler *> gap_scan_event_handlers_;
-#ifdef USE_ESP32_BLE_CLIENT
-  std::vector<GATTcEventHandler *> gattc_event_handlers_;
+  // Handler vectors - use StaticVector when counts are known at compile time
+#ifdef ESPHOME_ESP32_BLE_GAP_EVENT_HANDLER_COUNT
+  StaticVector<GAPEventHandler *, ESPHOME_ESP32_BLE_GAP_EVENT_HANDLER_COUNT> gap_event_handlers_;
 #endif
-#ifdef USE_ESP32_BLE_SERVER
-  std::vector<GATTsEventHandler *> gatts_event_handlers_;
+#ifdef ESPHOME_ESP32_BLE_GAP_SCAN_EVENT_HANDLER_COUNT
+  StaticVector<GAPScanEventHandler *, ESPHOME_ESP32_BLE_GAP_SCAN_EVENT_HANDLER_COUNT> gap_scan_event_handlers_;
+#endif
+#if defined(USE_ESP32_BLE_CLIENT) && defined(ESPHOME_ESP32_BLE_GATTC_EVENT_HANDLER_COUNT)
+  StaticVector<GATTcEventHandler *, ESPHOME_ESP32_BLE_GATTC_EVENT_HANDLER_COUNT> gattc_event_handlers_;
+#endif
+#if defined(USE_ESP32_BLE_SERVER) && defined(ESPHOME_ESP32_BLE_GATTS_EVENT_HANDLER_COUNT)
+  StaticVector<GATTsEventHandler *, ESPHOME_ESP32_BLE_GATTS_EVENT_HANDLER_COUNT> gatts_event_handlers_;
+#endif
+#ifdef ESPHOME_ESP32_BLE_BLE_STATUS_EVENT_HANDLER_COUNT
+  StaticVector<BLEStatusEventHandler *, ESPHOME_ESP32_BLE_BLE_STATUS_EVENT_HANDLER_COUNT> ble_status_event_handlers_;
 #endif
-  std::vector<BLEStatusEventHandler *> ble_status_event_handlers_;
 
   // Large objects (size depends on template parameters, but typically aligned to 4 bytes)
   esphome::LockFreeQueue<BLEEvent, MAX_BLE_QUEUE_SIZE> ble_events_;
diff --git a/esphome/components/esp32_ble_beacon/__init__.py b/esphome/components/esp32_ble_beacon/__init__.py
index 794f5637a4..ba5ae4331c 100644
--- a/esphome/components/esp32_ble_beacon/__init__.py
+++ b/esphome/components/esp32_ble_beacon/__init__.py
@@ -74,7 +74,7 @@ async def to_code(config):
     var = cg.new_Pvariable(config[CONF_ID], uuid_arr)
 
     parent = await cg.get_variable(config[esp32_ble.CONF_BLE_ID])
-    cg.add(parent.register_gap_event_handler(var))
+    esp32_ble.register_gap_event_handler(parent, var)
 
     await cg.register_component(var, config)
     cg.add(var.set_major(config[CONF_MAJOR]))
diff --git a/esphome/components/esp32_ble_server/__init__.py b/esphome/components/esp32_ble_server/__init__.py
index 10fa09fcc3..55310f3275 100644
--- a/esphome/components/esp32_ble_server/__init__.py
+++ b/esphome/components/esp32_ble_server/__init__.py
@@ -546,8 +546,8 @@ async def to_code(config):
     await cg.register_component(var, config)
 
     parent = await cg.get_variable(config[esp32_ble.CONF_BLE_ID])
-    cg.add(parent.register_gatts_event_handler(var))
-    cg.add(parent.register_ble_status_event_handler(var))
+    esp32_ble.register_gatts_event_handler(parent, var)
+    esp32_ble.register_ble_status_event_handler(parent, var)
     cg.add(var.set_parent(parent))
     cg.add(parent.advertising_set_appearance(config[CONF_APPEARANCE]))
     if CONF_MANUFACTURER_DATA in config:
diff --git a/esphome/components/esp32_ble_tracker/__init__.py b/esphome/components/esp32_ble_tracker/__init__.py
index 8c7f3e3930..5910be67af 100644
--- a/esphome/components/esp32_ble_tracker/__init__.py
+++ b/esphome/components/esp32_ble_tracker/__init__.py
@@ -246,10 +246,10 @@ async def to_code(config):
     await cg.register_component(var, config)
 
     parent = await cg.get_variable(config[esp32_ble.CONF_BLE_ID])
-    cg.add(parent.register_gap_event_handler(var))
-    cg.add(parent.register_gap_scan_event_handler(var))
-    cg.add(parent.register_gattc_event_handler(var))
-    cg.add(parent.register_ble_status_event_handler(var))
+    esp32_ble.register_gap_event_handler(parent, var)
+    esp32_ble.register_gap_scan_event_handler(parent, var)
+    esp32_ble.register_gattc_event_handler(parent, var)
+    esp32_ble.register_ble_status_event_handler(parent, var)
     cg.add(var.set_parent(parent))
 
     params = config[CONF_SCAN_PARAMETERS]
diff --git a/esphome/core/defines.h b/esphome/core/defines.h
index ae44e16624..614689caa6 100644
--- a/esphome/core/defines.h
+++ b/esphome/core/defines.h
@@ -177,6 +177,11 @@
 #define USE_ESP32_BLE_SERVER_ON_DISCONNECT
 #define ESPHOME_ESP32_BLE_TRACKER_LISTENER_COUNT 1
 #define ESPHOME_ESP32_BLE_TRACKER_CLIENT_COUNT 1
+#define ESPHOME_ESP32_BLE_GAP_EVENT_HANDLER_COUNT 2
+#define ESPHOME_ESP32_BLE_GAP_SCAN_EVENT_HANDLER_COUNT 1
+#define ESPHOME_ESP32_BLE_GATTC_EVENT_HANDLER_COUNT 1
+#define ESPHOME_ESP32_BLE_GATTS_EVENT_HANDLER_COUNT 1
+#define ESPHOME_ESP32_BLE_BLE_STATUS_EVENT_HANDLER_COUNT 2
 #define USE_ESP32_CAMERA_JPEG_ENCODER
 #define USE_I2C
 #define USE_IMPROV

From 6f2c7c0e5d922fdfad8483b85b53cf15e9e6c131 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Sun, 12 Oct 2025 11:13:14 -1000
Subject: [PATCH 37/90] fixes

---
 esphome/components/esp32_ble/__init__.py | 20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/esphome/components/esp32_ble/__init__.py b/esphome/components/esp32_ble/__init__.py
index d2ce4716f4..9d2e3b6004 100644
--- a/esphome/components/esp32_ble/__init__.py
+++ b/esphome/components/esp32_ble/__init__.py
@@ -17,7 +17,7 @@ from esphome.const import (
     CONF_NAME,
     CONF_NAME_ADD_MAC_SUFFIX,
 )
-from esphome.core import CORE, TimePeriod
+from esphome.core import CORE, CoroPriority, TimePeriod, coroutine_with_priority
 import esphome.final_validate as fv
 
 DEPENDENCIES = ["esp32"]
@@ -421,6 +421,16 @@ def final_validation(config):
     # For newer chips (C3/S3/etc), different configs are used automatically
     add_idf_sdkconfig_option("CONFIG_BTDM_CTRL_BLE_MAX_CONN", max_connections)
 
+    return config
+
+
+FINAL_VALIDATE_SCHEMA = final_validation
+
+
+# This needs to be run as a job with very low priority so that all components have
+# a chance to register their handlers before the counts are added to defines.
+@coroutine_with_priority(CoroPriority.FINAL)
+async def _add_ble_handler_defines():
     # Add defines for StaticVector sizing based on handler registration counts
     # Only define if count > 0 to avoid allocating unnecessary memory
     if _handler_counts.gap_event > 0:
@@ -446,11 +456,6 @@ def final_validation(config):
             _handler_counts.ble_status_event,
         )
 
-    return config
-
-
-FINAL_VALIDATE_SCHEMA = final_validation
-
 
 async def to_code(config):
     var = cg.new_Pvariable(config[CONF_ID])
@@ -506,6 +511,9 @@ async def to_code(config):
         cg.add_define("USE_ESP32_BLE_ADVERTISING")
         cg.add_define("USE_ESP32_BLE_UUID")
 
+    # Schedule the handler defines to be added after all components register
+    CORE.add_job(_add_ble_handler_defines)
+
 
 @automation.register_condition("ble.enabled", BLEEnabledCondition, cv.Schema({}))
 async def ble_enabled_to_code(config, condition_id, template_arg, args):

From 26ebfa490690ec0e59dd1ee90965634e3ee8ce12 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Sun, 12 Oct 2025 11:19:58 -1000
Subject: [PATCH 38/90] cleaner

---
 esphome/components/esp32_ble/ble.cpp | 30 +++++++++++-----------------
 esphome/components/esp32_ble/ble.h   | 26 ++++++++----------------
 2 files changed, 20 insertions(+), 36 deletions(-)

diff --git a/esphome/components/esp32_ble/ble.cpp b/esphome/components/esp32_ble/ble.cpp
index ca119f8836..79a2190ee9 100644
--- a/esphome/components/esp32_ble/ble.cpp
+++ b/esphome/components/esp32_ble/ble.cpp
@@ -182,32 +182,26 @@ bool ESP32BLE::ble_setup_() {
   }
 
 #ifdef ESPHOME_ESP32_BLE_GAP_EVENT_HANDLER_COUNT
-  if (!this->gap_event_handlers_.empty()) {
-    err = esp_ble_gap_register_callback(ESP32BLE::gap_event_handler);
-    if (err != ESP_OK) {
-      ESP_LOGE(TAG, "esp_ble_gap_register_callback failed: %d", err);
-      return false;
-    }
+  err = esp_ble_gap_register_callback(ESP32BLE::gap_event_handler);
+  if (err != ESP_OK) {
+    ESP_LOGE(TAG, "esp_ble_gap_register_callback failed: %d", err);
+    return false;
   }
 #endif
 
 #if defined(USE_ESP32_BLE_SERVER) && defined(ESPHOME_ESP32_BLE_GATTS_EVENT_HANDLER_COUNT)
-  if (!this->gatts_event_handlers_.empty()) {
-    err = esp_ble_gatts_register_callback(ESP32BLE::gatts_event_handler);
-    if (err != ESP_OK) {
-      ESP_LOGE(TAG, "esp_ble_gatts_register_callback failed: %d", err);
-      return false;
-    }
+  err = esp_ble_gatts_register_callback(ESP32BLE::gatts_event_handler);
+  if (err != ESP_OK) {
+    ESP_LOGE(TAG, "esp_ble_gatts_register_callback failed: %d", err);
+    return false;
   }
 #endif
 
 #if defined(USE_ESP32_BLE_CLIENT) && defined(ESPHOME_ESP32_BLE_GATTC_EVENT_HANDLER_COUNT)
-  if (!this->gattc_event_handlers_.empty()) {
-    err = esp_ble_gattc_register_callback(ESP32BLE::gattc_event_handler);
-    if (err != ESP_OK) {
-      ESP_LOGE(TAG, "esp_ble_gattc_register_callback failed: %d", err);
-      return false;
-    }
+  err = esp_ble_gattc_register_callback(ESP32BLE::gattc_event_handler);
+  if (err != ESP_OK) {
+    ESP_LOGE(TAG, "esp_ble_gattc_register_callback failed: %d", err);
+    return false;
   }
 #endif
 
diff --git a/esphome/components/esp32_ble/ble.h b/esphome/components/esp32_ble/ble.h
index 617047372b..dc973f0e82 100644
--- a/esphome/components/esp32_ble/ble.h
+++ b/esphome/components/esp32_ble/ble.h
@@ -125,35 +125,25 @@ class ESP32BLE : public Component {
   void advertising_register_raw_advertisement_callback(std::function<void(bool)> &&callback);
 #endif
 
-  void register_gap_event_handler(GAPEventHandler *handler) {
 #ifdef ESPHOME_ESP32_BLE_GAP_EVENT_HANDLER_COUNT
-    this->gap_event_handlers_.push_back(handler);
+  void register_gap_event_handler(GAPEventHandler *handler) { this->gap_event_handlers_.push_back(handler); }
 #endif
-  }
-  void register_gap_scan_event_handler(GAPScanEventHandler *handler) {
 #ifdef ESPHOME_ESP32_BLE_GAP_SCAN_EVENT_HANDLER_COUNT
+  void register_gap_scan_event_handler(GAPScanEventHandler *handler) {
     this->gap_scan_event_handlers_.push_back(handler);
-#endif
-  }
-#ifdef USE_ESP32_BLE_CLIENT
-  void register_gattc_event_handler(GATTcEventHandler *handler) {
-#ifdef ESPHOME_ESP32_BLE_GATTC_EVENT_HANDLER_COUNT
-    this->gattc_event_handlers_.push_back(handler);
-#endif
   }
 #endif
-#ifdef USE_ESP32_BLE_SERVER
-  void register_gatts_event_handler(GATTsEventHandler *handler) {
-#ifdef ESPHOME_ESP32_BLE_GATTS_EVENT_HANDLER_COUNT
-    this->gatts_event_handlers_.push_back(handler);
+#if defined(USE_ESP32_BLE_CLIENT) && defined(ESPHOME_ESP32_BLE_GATTC_EVENT_HANDLER_COUNT)
+  void register_gattc_event_handler(GATTcEventHandler *handler) { this->gattc_event_handlers_.push_back(handler); }
 #endif
-  }
+#if defined(USE_ESP32_BLE_SERVER) && defined(ESPHOME_ESP32_BLE_GATTS_EVENT_HANDLER_COUNT)
+  void register_gatts_event_handler(GATTsEventHandler *handler) { this->gatts_event_handlers_.push_back(handler); }
 #endif
-  void register_ble_status_event_handler(BLEStatusEventHandler *handler) {
 #ifdef ESPHOME_ESP32_BLE_BLE_STATUS_EVENT_HANDLER_COUNT
+  void register_ble_status_event_handler(BLEStatusEventHandler *handler) {
     this->ble_status_event_handlers_.push_back(handler);
-#endif
   }
+#endif
   void set_enable_on_boot(bool enable_on_boot) { this->enable_on_boot_ = enable_on_boot; }
 
  protected:

From 7c8f8e282d77c98a8581a2e91aae890e1c7b3acb Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Sun, 12 Oct 2025 12:52:38 -1000
Subject: [PATCH 39/90] Fix log retrieval with FQDN when mDNS is disabled

---
 esphome/__main__.py           | 15 +++++++-----
 tests/unit_tests/test_main.py | 45 ++++++++++++++++++++++++++++-------
 2 files changed, 46 insertions(+), 14 deletions(-)

diff --git a/esphome/__main__.py b/esphome/__main__.py
index be4551f6b5..8e0c475525 100644
--- a/esphome/__main__.py
+++ b/esphome/__main__.py
@@ -268,8 +268,10 @@ def has_ip_address() -> bool:
 
 
 def has_resolvable_address() -> bool:
-    """Check if CORE.address is resolvable (via mDNS or is an IP address)."""
-    return has_mdns() or has_ip_address()
+    """Check if CORE.address is resolvable (via mDNS, DNS, or is an IP address)."""
+    # Any address (IP, mDNS hostname, or regular DNS hostname) is resolvable
+    # The resolve_ip_address() function in helpers.py handles all types via AsyncResolver
+    return CORE.address is not None
 
 
 def mqtt_get_ip(config: ConfigType, username: str, password: str, client_id: str):
@@ -578,11 +580,12 @@ def show_logs(config: ConfigType, args: ArgsProtocol, devices: list[str]) -> int
     if has_api():
         addresses_to_use: list[str] | None = None
 
-        if port_type == "NETWORK" and (has_mdns() or is_ip_address(port)):
+        if port_type == "NETWORK":
+            # Network addresses (IPs, mDNS names, or regular DNS hostnames) can be used
+            # The resolve_ip_address() function in helpers.py handles all types
             addresses_to_use = devices
-        elif port_type in ("NETWORK", "MQTT", "MQTTIP") and has_mqtt_ip_lookup():
-            # Only use MQTT IP lookup if the first condition didn't match
-            # (for MQTT/MQTTIP types, or for NETWORK when mdns/ip check fails)
+        elif port_type in ("MQTT", "MQTTIP") and has_mqtt_ip_lookup():
+            # Use MQTT IP lookup for MQTT/MQTTIP types
             addresses_to_use = mqtt_get_ip(
                 config, args.username, args.password, args.client_id
             )
diff --git a/tests/unit_tests/test_main.py b/tests/unit_tests/test_main.py
index e35378145a..becf911fa3 100644
--- a/tests/unit_tests/test_main.py
+++ b/tests/unit_tests/test_main.py
@@ -1203,6 +1203,31 @@ def test_show_logs_api(
     )
 
 
+@patch("esphome.components.api.client.run_logs")
+def test_show_logs_api_with_fqdn_mdns_disabled(
+    mock_run_logs: Mock,
+) -> None:
+    """Test show_logs with API using FQDN when mDNS is disabled."""
+    setup_core(
+        config={
+            "logger": {},
+            CONF_API: {},
+            CONF_MDNS: {CONF_DISABLED: True},
+        },
+        platform=PLATFORM_ESP32,
+    )
+    mock_run_logs.return_value = 0
+
+    args = MockArgs()
+    devices = ["device.example.com"]
+
+    result = show_logs(CORE.config, args, devices)
+
+    assert result == 0
+    # Should use the FQDN directly, not try MQTT lookup
+    mock_run_logs.assert_called_once_with(CORE.config, ["device.example.com"])
+
+
 @patch("esphome.components.api.client.run_logs")
 def test_show_logs_api_with_mqtt_fallback(
     mock_run_logs: Mock,
@@ -1222,7 +1247,7 @@ def test_show_logs_api_with_mqtt_fallback(
     mock_mqtt_get_ip.return_value = ["192.168.1.200"]
 
     args = MockArgs(username="user", password="pass", client_id="client")
-    devices = ["device.local"]
+    devices = ["MQTTIP"]
 
     result = show_logs(CORE.config, args, devices)
 
@@ -1487,27 +1512,31 @@ def test_mqtt_get_ip() -> None:
 def test_has_resolvable_address() -> None:
     """Test has_resolvable_address function."""
 
-    # Test with mDNS enabled and hostname address
+    # Test with mDNS enabled and .local hostname address
     setup_core(config={}, address="esphome-device.local")
     assert has_resolvable_address() is True
 
-    # Test with mDNS disabled and hostname address
+    # Test with mDNS disabled and .local hostname address (still resolvable via DNS)
     setup_core(
         config={CONF_MDNS: {CONF_DISABLED: True}}, address="esphome-device.local"
     )
-    assert has_resolvable_address() is False
+    assert has_resolvable_address() is True
 
-    # Test with IP address (mDNS doesn't matter)
+    # Test with mDNS disabled and regular DNS hostname (resolvable)
+    setup_core(config={CONF_MDNS: {CONF_DISABLED: True}}, address="device.example.com")
+    assert has_resolvable_address() is True
+
+    # Test with IP address (always resolvable, mDNS doesn't matter)
     setup_core(config={}, address="192.168.1.100")
     assert has_resolvable_address() is True
 
-    # Test with IP address and mDNS disabled
+    # Test with IP address and mDNS disabled (still resolvable)
     setup_core(config={CONF_MDNS: {CONF_DISABLED: True}}, address="192.168.1.100")
     assert has_resolvable_address() is True
 
-    # Test with no address but mDNS enabled (can still resolve mDNS names)
+    # Test with no address
     setup_core(config={}, address=None)
-    assert has_resolvable_address() is True
+    assert has_resolvable_address() is False
 
     # Test with no address and mDNS disabled
     setup_core(config={CONF_MDNS: {CONF_DISABLED: True}}, address=None)

From a9fd0a3b26eed1059aa82390b0addbc00e1d916d Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Sun, 12 Oct 2025 18:21:14 -1000
Subject: [PATCH 40/90] fixed_vector, bluetooth services

---
 esphome/components/api/api.proto              |  4 +-
 esphome/components/api/api_options.proto      |  6 +++
 esphome/components/api/api_pb2.h              |  4 +-
 esphome/components/api/proto.h                | 26 +++++++++--
 .../bluetooth_proxy/bluetooth_connection.cpp  |  8 ++--
 esphome/core/helpers.h                        | 46 +++++++++++++++++++
 script/api_protobuf/api_protobuf.py           |  4 ++
 7 files changed, 85 insertions(+), 13 deletions(-)

diff --git a/esphome/components/api/api.proto b/esphome/components/api/api.proto
index 87f477799d..9b714d00f1 100644
--- a/esphome/components/api/api.proto
+++ b/esphome/components/api/api.proto
@@ -1519,7 +1519,7 @@ message BluetoothGATTCharacteristic {
   repeated uint64 uuid = 1 [(fixed_array_size) = 2, (fixed_array_skip_zero) = true];
   uint32 handle = 2;
   uint32 properties = 3;
-  repeated BluetoothGATTDescriptor descriptors = 4;
+  repeated BluetoothGATTDescriptor descriptors = 4 [(fixed_vector) = true];
 
   // New field for efficient UUID (v1.12+)
   // Only one of uuid or short_uuid will be set.
@@ -1531,7 +1531,7 @@ message BluetoothGATTCharacteristic {
 message BluetoothGATTService {
   repeated uint64 uuid = 1 [(fixed_array_size) = 2, (fixed_array_skip_zero) = true];
   uint32 handle = 2;
-  repeated BluetoothGATTCharacteristic characteristics = 3;
+  repeated BluetoothGATTCharacteristic characteristics = 3 [(fixed_vector) = true];
 
   // New field for efficient UUID (v1.12+)
   // Only one of uuid or short_uuid will be set.
diff --git a/esphome/components/api/api_options.proto b/esphome/components/api/api_options.proto
index 633f39b552..ead8ac0bbc 100644
--- a/esphome/components/api/api_options.proto
+++ b/esphome/components/api/api_options.proto
@@ -64,4 +64,10 @@ extend google.protobuf.FieldOptions {
     // This is typically done through methods returning const T& or special accessor
     // methods like get_options() or supported_modes_for_api_().
     optional string container_pointer = 50001;
+
+    // fixed_vector: Use FixedVector instead of std::vector for repeated fields
+    // When set, the repeated field will use FixedVector<T> which requires calling
+    // init(size) before adding elements. This eliminates std::vector template overhead
+    // and is ideal when the exact size is known before populating the array.
+    optional bool fixed_vector = 50013 [default=false];
 }
diff --git a/esphome/components/api/api_pb2.h b/esphome/components/api/api_pb2.h
index d9e68ece9b..1798458393 100644
--- a/esphome/components/api/api_pb2.h
+++ b/esphome/components/api/api_pb2.h
@@ -1923,7 +1923,7 @@ class BluetoothGATTCharacteristic final : public ProtoMessage {
   std::array<uint64_t, 2> uuid{};
   uint32_t handle{0};
   uint32_t properties{0};
-  std::vector<BluetoothGATTDescriptor> descriptors{};
+  FixedVector<BluetoothGATTDescriptor> descriptors{};
   uint32_t short_uuid{0};
   void encode(ProtoWriteBuffer buffer) const override;
   void calculate_size(ProtoSize &size) const override;
@@ -1937,7 +1937,7 @@ class BluetoothGATTService final : public ProtoMessage {
  public:
   std::array<uint64_t, 2> uuid{};
   uint32_t handle{0};
-  std::vector<BluetoothGATTCharacteristic> characteristics{};
+  FixedVector<BluetoothGATTCharacteristic> characteristics{};
   uint32_t short_uuid{0};
   void encode(ProtoWriteBuffer buffer) const override;
   void calculate_size(ProtoSize &size) const override;
diff --git a/esphome/components/api/proto.h b/esphome/components/api/proto.h
index 9d780692ec..a6a09bf7c5 100644
--- a/esphome/components/api/proto.h
+++ b/esphome/components/api/proto.h
@@ -749,13 +749,29 @@ class ProtoSize {
   template<typename MessageType>
   inline void add_repeated_message(uint32_t field_id_size, const std::vector<MessageType> &messages) {
     // Skip if the vector is empty
-    if (messages.empty()) {
-      return;
+    if (!messages.empty()) {
+      // Use the force version for all messages in the repeated field
+      for (const auto &message : messages) {
+        add_message_object_force(field_id_size, message);
+      }
     }
+  }
 
-    // Use the force version for all messages in the repeated field
-    for (const auto &message : messages) {
-      add_message_object_force(field_id_size, message);
+  /**
+   * @brief Calculates and adds the sizes of all messages in a repeated field to the total message size (FixedVector
+   * version)
+   *
+   * @tparam MessageType The type of the nested messages in the FixedVector
+   * @param messages FixedVector of message objects
+   */
+  template<typename MessageType>
+  inline void add_repeated_message(uint32_t field_id_size, const FixedVector<MessageType> &messages) {
+    // Skip if the fixed vector is empty
+    if (!messages.empty()) {
+      // Use the force version for all messages in the repeated field
+      for (const auto &message : messages) {
+        add_message_object_force(field_id_size, message);
+      }
     }
   }
 };
diff --git a/esphome/components/bluetooth_proxy/bluetooth_connection.cpp b/esphome/components/bluetooth_proxy/bluetooth_connection.cpp
index cde82fbfb0..6f172b0bcf 100644
--- a/esphome/components/bluetooth_proxy/bluetooth_connection.cpp
+++ b/esphome/components/bluetooth_proxy/bluetooth_connection.cpp
@@ -230,8 +230,8 @@ void BluetoothConnection::send_service_for_discovery_() {
     service_resp.handle = service_result.start_handle;
 
     if (total_char_count > 0) {
-      // Reserve space and process characteristics
-      service_resp.characteristics.reserve(total_char_count);
+      // Initialize FixedVector with exact count and process characteristics
+      service_resp.characteristics.init(total_char_count);
       uint16_t char_offset = 0;
       esp_gattc_char_elem_t char_result;
       while (true) {  // characteristics
@@ -275,8 +275,8 @@ void BluetoothConnection::send_service_for_discovery_() {
           continue;
         }
 
-        // Reserve space and process descriptors
-        characteristic_resp.descriptors.reserve(total_desc_count);
+        // Initialize FixedVector with exact count and process descriptors
+        characteristic_resp.descriptors.init(total_desc_count);
         uint16_t desc_offset = 0;
         esp_gattc_descr_elem_t desc_result;
         while (true) {  // descriptors
diff --git a/esphome/core/helpers.h b/esphome/core/helpers.h
index b5a0a1c8ac..2bdfcb4e2a 100644
--- a/esphome/core/helpers.h
+++ b/esphome/core/helpers.h
@@ -181,6 +181,31 @@ template<typename T> class FixedVector {
   FixedVector(const FixedVector &) = delete;
   FixedVector &operator=(const FixedVector &) = delete;
 
+  // Enable move semantics for use in containers
+  FixedVector(FixedVector &&other) noexcept : data_(other.data_), size_(other.size_), capacity_(other.capacity_) {
+    other.data_ = nullptr;
+    other.size_ = 0;
+    other.capacity_ = 0;
+  }
+
+  FixedVector &operator=(FixedVector &&other) noexcept {
+    if (this != &other) {
+      // Delete our current data
+      if (data_ != nullptr) {
+        delete[] data_;
+      }
+      // Take ownership of other's data
+      data_ = other.data_;
+      size_ = other.size_;
+      capacity_ = other.capacity_;
+      // Leave other in valid empty state
+      other.data_ = nullptr;
+      other.size_ = 0;
+      other.capacity_ = 0;
+    }
+    return *this;
+  }
+
   // Allocate capacity - can only be called once on empty vector
   void init(size_t n) {
     if (data_ == nullptr && n > 0) {
@@ -199,12 +224,33 @@ template<typename T> class FixedVector {
     }
   }
 
+  /// Construct element in place and return reference
+  /// Caller must ensure sufficient capacity was allocated via init()
+  T &emplace_back() {
+    if (size_ < capacity_) {
+      return data_[size_++];
+    }
+    // Should never happen with proper init() - return last element to avoid crash
+    return data_[capacity_ - 1];
+  }
+
+  /// Access last element
+  T &back() { return data_[size_ - 1]; }
+  const T &back() const { return data_[size_ - 1]; }
+
   size_t size() const { return size_; }
+  bool empty() const { return size_ == 0; }
 
   /// Access element without bounds checking (matches std::vector behavior)
   /// Caller must ensure index is valid (i < size())
   T &operator[](size_t i) { return data_[i]; }
   const T &operator[](size_t i) const { return data_[i]; }
+
+  /// Iterators for range-based for loops
+  T *begin() { return data_; }
+  T *end() { return data_ + size_; }
+  const T *begin() const { return data_; }
+  const T *end() const { return data_ + size_; }
 };
 
 ///@}
diff --git a/script/api_protobuf/api_protobuf.py b/script/api_protobuf/api_protobuf.py
index 487c187372..9a55f1d136 100755
--- a/script/api_protobuf/api_protobuf.py
+++ b/script/api_protobuf/api_protobuf.py
@@ -1415,6 +1415,8 @@ class RepeatedTypeInfo(TypeInfo):
         # Check if this is a pointer field by looking for container_pointer option
         self._container_type = get_field_opt(field, pb.container_pointer, "")
         self._use_pointer = bool(self._container_type)
+        # Check if this should use FixedVector instead of std::vector
+        self._use_fixed_vector = get_field_opt(field, pb.fixed_vector, False)
 
         # For repeated fields, we need to get the base type info
         # but we can't call create_field_type_info as it would cause recursion
@@ -1438,6 +1440,8 @@ class RepeatedTypeInfo(TypeInfo):
             if "<" in self._container_type and ">" in self._container_type:
                 return f"const {self._container_type}*"
             return f"const {self._container_type}<{self._ti.cpp_type}>*"
+        if self._use_fixed_vector:
+            return f"FixedVector<{self._ti.cpp_type}>"
         return f"std::vector<{self._ti.cpp_type}>"
 
     @property

From 347501d895cb42d1a15633d4b2fd684ae6a2af6a Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Sun, 12 Oct 2025 19:39:55 -1000
Subject: [PATCH 41/90] wifi fixed vector

---
 esphome/components/wifi/wifi_component.cpp    |  2 +-
 esphome/components/wifi/wifi_component.h      |  4 +-
 .../wifi/wifi_component_esp8266.cpp           |  8 ++++
 .../wifi/wifi_component_esp_idf.cpp           |  5 +-
 .../wifi/wifi_component_libretiny.cpp         |  2 +-
 esphome/core/helpers.h                        | 46 +++++++++++++++----
 6 files changed, 51 insertions(+), 16 deletions(-)

diff --git a/esphome/components/wifi/wifi_component.cpp b/esphome/components/wifi/wifi_component.cpp
index 2e083d4c68..1bb2674ad7 100644
--- a/esphome/components/wifi/wifi_component.cpp
+++ b/esphome/components/wifi/wifi_component.cpp
@@ -552,7 +552,7 @@ void WiFiComponent::start_scanning() {
 // Using insertion sort instead of std::stable_sort saves flash memory
 // by avoiding template instantiations (std::rotate, std::stable_sort, lambdas)
 // IMPORTANT: This sort is stable (preserves relative order of equal elements)
-static void insertion_sort_scan_results(std::vector<WiFiScanResult> &results) {
+static void insertion_sort_scan_results(FixedVector<WiFiScanResult> &results) {
   const size_t size = results.size();
   for (size_t i = 1; i < size; i++) {
     // Make a copy to avoid issues with move semantics during comparison
diff --git a/esphome/components/wifi/wifi_component.h b/esphome/components/wifi/wifi_component.h
index ee62ec1a69..e1c3d6df88 100644
--- a/esphome/components/wifi/wifi_component.h
+++ b/esphome/components/wifi/wifi_component.h
@@ -278,7 +278,7 @@ class WiFiComponent : public Component {
   std::string get_use_address() const;
   void set_use_address(const std::string &use_address);
 
-  const std::vector<WiFiScanResult> &get_scan_result() const { return scan_result_; }
+  const FixedVector<WiFiScanResult> &get_scan_result() const { return scan_result_; }
 
   network::IPAddress wifi_soft_ap_ip();
 
@@ -385,7 +385,7 @@ class WiFiComponent : public Component {
   std::string use_address_;
   std::vector<WiFiAP> sta_;
   std::vector<WiFiSTAPriority> sta_priorities_;
-  std::vector<WiFiScanResult> scan_result_;
+  FixedVector<WiFiScanResult> scan_result_;
   WiFiAP selected_ap_;
   WiFiAP ap_;
   optional<float> output_power_;
diff --git a/esphome/components/wifi/wifi_component_esp8266.cpp b/esphome/components/wifi/wifi_component_esp8266.cpp
index 3b3b4b139c..59909b2cb5 100644
--- a/esphome/components/wifi/wifi_component_esp8266.cpp
+++ b/esphome/components/wifi/wifi_component_esp8266.cpp
@@ -696,7 +696,15 @@ void WiFiComponent::wifi_scan_done_callback_(void *arg, STATUS status) {
     this->retry_connect();
     return;
   }
+
+  // Count the number of results first
   auto *head = reinterpret_cast<bss_info *>(arg);
+  size_t count = 0;
+  for (bss_info *it = head; it != nullptr; it = STAILQ_NEXT(it, next)) {
+    count++;
+  }
+
+  this->scan_result_.init(count);
   for (bss_info *it = head; it != nullptr; it = STAILQ_NEXT(it, next)) {
     WiFiScanResult res({it->bssid[0], it->bssid[1], it->bssid[2], it->bssid[3], it->bssid[4], it->bssid[5]},
                        std::string(reinterpret_cast<char *>(it->ssid), it->ssid_len), it->channel, it->rssi,
diff --git a/esphome/components/wifi/wifi_component_esp_idf.cpp b/esphome/components/wifi/wifi_component_esp_idf.cpp
index ccec800205..4c719ef4c3 100644
--- a/esphome/components/wifi/wifi_component_esp_idf.cpp
+++ b/esphome/components/wifi/wifi_component_esp_idf.cpp
@@ -763,8 +763,9 @@ void WiFiComponent::wifi_process_event_(IDFWiFiEvent *data) {
     const auto &it = data->data.sta_scan_done;
     ESP_LOGV(TAG, "Scan done: status=%" PRIu32 " number=%u scan_id=%u", it.status, it.number, it.scan_id);
 
-    scan_result_.clear();
     this->scan_done_ = true;
+    scan_result_.clear();
+
     if (it.status != 0) {
       // scan error
       return;
@@ -784,7 +785,7 @@ void WiFiComponent::wifi_process_event_(IDFWiFiEvent *data) {
     }
     records.resize(number);
 
-    scan_result_.reserve(number);
+    scan_result_.init(number);
     for (int i = 0; i < number; i++) {
       auto &record = records[i];
       bssid_t bssid;
diff --git a/esphome/components/wifi/wifi_component_libretiny.cpp b/esphome/components/wifi/wifi_component_libretiny.cpp
index b15f710150..cb179d9022 100644
--- a/esphome/components/wifi/wifi_component_libretiny.cpp
+++ b/esphome/components/wifi/wifi_component_libretiny.cpp
@@ -411,7 +411,7 @@ void WiFiComponent::wifi_scan_done_callback_() {
   if (num < 0)
     return;
 
-  this->scan_result_.reserve(static_cast<unsigned int>(num));
+  this->scan_result_.init(static_cast<unsigned int>(num));
   for (int i = 0; i < num; i++) {
     String ssid = WiFi.SSID(i);
     wifi_auth_mode_t authmode = WiFi.encryptionType(i);
diff --git a/esphome/core/helpers.h b/esphome/core/helpers.h
index b5a0a1c8ac..12e921e3be 100644
--- a/esphome/core/helpers.h
+++ b/esphome/core/helpers.h
@@ -168,34 +168,54 @@ template<typename T> class FixedVector {
   size_t size_{0};
   size_t capacity_{0};
 
+  // Helper to destroy elements and free memory
+  void cleanup_() {
+    if (data_ != nullptr) {
+      // Manually destroy all elements
+      for (size_t i = 0; i < size_; i++) {
+        data_[i].~T();
+      }
+      // Free raw memory
+      ::operator delete(data_);
+    }
+  }
+
  public:
   FixedVector() = default;
 
-  ~FixedVector() {
-    if (data_ != nullptr) {
-      delete[] data_;
-    }
-  }
+  ~FixedVector() { cleanup_(); }
 
   // Disable copy to avoid accidental copies
   FixedVector(const FixedVector &) = delete;
   FixedVector &operator=(const FixedVector &) = delete;
 
-  // Allocate capacity - can only be called once on empty vector
+  // Allocate capacity - can be called multiple times to reinit
   void init(size_t n) {
-    if (data_ == nullptr && n > 0) {
-      data_ = new T[n];
+    cleanup_();
+    data_ = nullptr;
+    capacity_ = 0;
+    size_ = 0;
+    if (n > 0) {
+      // Allocate raw memory without calling constructors
+      data_ = static_cast<T *>(::operator new(n * sizeof(T)));
       capacity_ = n;
-      size_ = 0;
     }
   }
 
+  // Clear the vector (reset size to 0, keep capacity)
+  void clear() { size_ = 0; }
+
+  // Check if vector is empty
+  bool empty() const { return size_ == 0; }
+
   /// Add element without bounds checking
   /// Caller must ensure sufficient capacity was allocated via init()
   /// Silently ignores pushes beyond capacity (no exception or assertion)
   void push_back(const T &value) {
     if (size_ < capacity_) {
-      data_[size_++] = value;
+      // Use placement new to construct the object in pre-allocated memory
+      new (&data_[size_]) T(value);
+      size_++;
     }
   }
 
@@ -205,6 +225,12 @@ template<typename T> class FixedVector {
   /// Caller must ensure index is valid (i < size())
   T &operator[](size_t i) { return data_[i]; }
   const T &operator[](size_t i) const { return data_[i]; }
+
+  // Iterator support for range-based for loops
+  T *begin() { return data_; }
+  T *end() { return data_ + size_; }
+  const T *begin() const { return data_; }
+  const T *end() const { return data_ + size_; }
 };
 
 ///@}

From 6f3a9966983806b52c0730995c01d478336b2264 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Sun, 12 Oct 2025 20:12:34 -1000
Subject: [PATCH 42/90] [wifi] Free scan results memory after successful
 connection

---
 esphome/components/wifi/__init__.py         | 21 +++++++++++++++++++++
 esphome/components/wifi/wifi_component.cpp  |  6 ++++++
 esphome/components/wifi/wifi_component.h    |  2 ++
 esphome/components/wifi_info/text_sensor.py |  4 +++-
 4 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/esphome/components/wifi/__init__.py b/esphome/components/wifi/__init__.py
index a784123006..286e66a06b 100644
--- a/esphome/components/wifi/__init__.py
+++ b/esphome/components/wifi/__init__.py
@@ -468,6 +468,27 @@ async def wifi_disable_to_code(config, action_id, template_arg, args):
     return cg.new_Pvariable(action_id, template_arg)
 
 
+_FLAGS = {"keep_scan_results": False}
+
+
+def request_wifi_scan_results():
+    """Request that WiFi scan results be kept in memory after connection.
+
+    Components that need access to scan results after WiFi is connected should
+    call this function during their code generation. This prevents the WiFi component from
+    freeing scan result memory after successful connection.
+    """
+    _FLAGS["keep_scan_results"] = True
+
+
+@coroutine_with_priority(CoroPriority.FINAL)
+async def final_step():
+    """Final code generation step to configure scan result retention."""
+    if _FLAGS["keep_scan_results"]:
+        wifi_var = cg.MockObj(id="global_wifi_component", base="wifi::WiFiComponent *")
+        cg.add(wifi_var.set_keep_scan_results(True))
+
+
 @automation.register_action(
     "wifi.configure",
     WiFiConfigureAction,
diff --git a/esphome/components/wifi/wifi_component.cpp b/esphome/components/wifi/wifi_component.cpp
index 71ee4271ba..0a30b82aaf 100644
--- a/esphome/components/wifi/wifi_component.cpp
+++ b/esphome/components/wifi/wifi_component.cpp
@@ -716,6 +716,12 @@ void WiFiComponent::check_connecting_finished() {
     this->state_ = WIFI_COMPONENT_STATE_STA_CONNECTED;
     this->num_retried_ = 0;
 
+    // Free scan results memory unless a component needs them
+    if (!this->keep_scan_results_) {
+      this->scan_result_.clear();
+      this->scan_result_.shrink_to_fit();
+    }
+
     if (this->fast_connect_) {
       this->save_fast_connect_settings_();
     }
diff --git a/esphome/components/wifi/wifi_component.h b/esphome/components/wifi/wifi_component.h
index ee62ec1a69..c0b63e1858 100644
--- a/esphome/components/wifi/wifi_component.h
+++ b/esphome/components/wifi/wifi_component.h
@@ -316,6 +316,7 @@ class WiFiComponent : public Component {
   int8_t wifi_rssi();
 
   void set_enable_on_boot(bool enable_on_boot) { this->enable_on_boot_ = enable_on_boot; }
+  void set_keep_scan_results(bool keep_scan_results) { this->keep_scan_results_ = keep_scan_results; }
 
   Trigger<> *get_connect_trigger() const { return this->connect_trigger_; };
   Trigger<> *get_disconnect_trigger() const { return this->disconnect_trigger_; };
@@ -424,6 +425,7 @@ class WiFiComponent : public Component {
 #endif
   bool enable_on_boot_;
   bool got_ipv4_address_{false};
+  bool keep_scan_results_{false};
 
   // Pointers at the end (naturally aligned)
   Trigger<> *connect_trigger_{new Trigger<>()};
diff --git a/esphome/components/wifi_info/text_sensor.py b/esphome/components/wifi_info/text_sensor.py
index 4ceb73a695..ac1c1bee05 100644
--- a/esphome/components/wifi_info/text_sensor.py
+++ b/esphome/components/wifi_info/text_sensor.py
@@ -1,5 +1,5 @@
 import esphome.codegen as cg
-from esphome.components import text_sensor
+from esphome.components import text_sensor, wifi
 import esphome.config_validation as cv
 from esphome.const import (
     CONF_BSSID,
@@ -77,6 +77,8 @@ async def to_code(config):
     await setup_conf(config, CONF_SSID)
     await setup_conf(config, CONF_BSSID)
     await setup_conf(config, CONF_MAC_ADDRESS)
+    if CONF_SCAN_RESULTS in config:
+        wifi.request_wifi_scan_results()
     await setup_conf(config, CONF_SCAN_RESULTS)
     await setup_conf(config, CONF_DNS_ADDRESS)
     if conf := config.get(CONF_IP_ADDRESS):

From 4d55c8f309283919b655847d53dbfbe76107ba3a Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Sun, 12 Oct 2025 20:20:17 -1000
Subject: [PATCH 43/90] preen

---
 esphome/components/wifi/__init__.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/esphome/components/wifi/__init__.py b/esphome/components/wifi/__init__.py
index 286e66a06b..9a7c4c1713 100644
--- a/esphome/components/wifi/__init__.py
+++ b/esphome/components/wifi/__init__.py
@@ -447,6 +447,8 @@ async def to_code(config):
             var.get_disconnect_trigger(), [], on_disconnect_config
         )
 
+    CORE.add_job(final_step)
+
 
 @automation.register_condition("wifi.connected", WiFiConnectedCondition, cv.Schema({}))
 async def wifi_connected_to_code(config, condition_id, template_arg, args):

From d191d1e99a3336dad8608e36bae52741b0ed91f1 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Sun, 12 Oct 2025 20:21:56 -1000
Subject: [PATCH 44/90] preen

---
 esphome/components/wifi/__init__.py | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/esphome/components/wifi/__init__.py b/esphome/components/wifi/__init__.py
index 9a7c4c1713..ae85e40357 100644
--- a/esphome/components/wifi/__init__.py
+++ b/esphome/components/wifi/__init__.py
@@ -487,8 +487,9 @@ def request_wifi_scan_results():
 async def final_step():
     """Final code generation step to configure scan result retention."""
     if _FLAGS["keep_scan_results"]:
-        wifi_var = cg.MockObj(id="global_wifi_component", base="wifi::WiFiComponent *")
-        cg.add(wifi_var.set_keep_scan_results(True))
+        cg.add(
+            cg.RawExpression("wifi::global_wifi_component->set_keep_scan_results(true)")
+        )
 
 
 @automation.register_action(

From dd09897a1d37491c99f2449f6bd652c74f96d0f5 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Sun, 12 Oct 2025 20:46:36 -1000
Subject: [PATCH 45/90] Update esphome/components/wifi_info/text_sensor.py

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
---
 esphome/components/wifi_info/text_sensor.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/esphome/components/wifi_info/text_sensor.py b/esphome/components/wifi_info/text_sensor.py
index ac1c1bee05..a4da582c55 100644
--- a/esphome/components/wifi_info/text_sensor.py
+++ b/esphome/components/wifi_info/text_sensor.py
@@ -78,8 +78,8 @@ async def to_code(config):
     await setup_conf(config, CONF_BSSID)
     await setup_conf(config, CONF_MAC_ADDRESS)
     if CONF_SCAN_RESULTS in config:
+        await setup_conf(config, CONF_SCAN_RESULTS)
         wifi.request_wifi_scan_results()
-    await setup_conf(config, CONF_SCAN_RESULTS)
     await setup_conf(config, CONF_DNS_ADDRESS)
     if conf := config.get(CONF_IP_ADDRESS):
         wifi_info = await text_sensor.new_text_sensor(config[CONF_IP_ADDRESS])

From 22370c0ad178ad9931cf4d54197a9edf52f04759 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Mon, 13 Oct 2025 14:03:08 -1000
Subject: [PATCH 46/90] merge

---
 esphome/core/helpers.h | 42 +++++++++++++++++++++++++++++++-----------
 1 file changed, 31 insertions(+), 11 deletions(-)

diff --git a/esphome/core/helpers.h b/esphome/core/helpers.h
index 80ce21af57..084ad28882 100644
--- a/esphome/core/helpers.h
+++ b/esphome/core/helpers.h
@@ -168,14 +168,22 @@ template<typename T> class FixedVector {
   size_t size_{0};
   size_t capacity_{0};
 
+  // Helper to destroy elements and free memory
+  void cleanup_() {
+    if (data_ != nullptr) {
+      // Manually destroy all elements
+      for (size_t i = 0; i < size_; i++) {
+        data_[i].~T();
+      }
+      // Free raw memory
+      ::operator delete(data_);
+    }
+  }
+
  public:
   FixedVector() = default;
 
-  ~FixedVector() {
-    if (data_ != nullptr) {
-      delete[] data_;
-    }
-  }
+  ~FixedVector() { cleanup_(); }
 
   // Enable move semantics for use in containers
   FixedVector(FixedVector &&other) noexcept : data_(other.data_), size_(other.size_), capacity_(other.capacity_) {
@@ -202,21 +210,33 @@ template<typename T> class FixedVector {
     return *this;
   }
 
-  // Allocate capacity - can only be called once on empty vector
+  // Allocate capacity - can be called multiple times to reinit
   void init(size_t n) {
-    if (data_ == nullptr && n > 0) {
-      data_ = new T[n];
+    cleanup_();
+    data_ = nullptr;
+    capacity_ = 0;
+    size_ = 0;
+    if (n > 0) {
+      // Allocate raw memory without calling constructors
+      data_ = static_cast<T *>(::operator new(n * sizeof(T)));
       capacity_ = n;
-      size_ = 0;
     }
   }
 
+  // Clear the vector (reset size to 0, keep capacity)
+  void clear() { size_ = 0; }
+
+  // Check if vector is empty
+  bool empty() const { return size_ == 0; }
+
   /// Add element without bounds checking
   /// Caller must ensure sufficient capacity was allocated via init()
   /// Silently ignores pushes beyond capacity (no exception or assertion)
   void push_back(const T &value) {
     if (size_ < capacity_) {
-      data_[size_++] = value;
+      // Use placement new to construct the object in pre-allocated memory
+      new (&data_[size_]) T(value);
+      size_++;
     }
   }
 
@@ -242,7 +262,7 @@ template<typename T> class FixedVector {
   T &operator[](size_t i) { return data_[i]; }
   const T &operator[](size_t i) const { return data_[i]; }
 
-  /// Iterators for range-based for loops
+  // Iterator support for range-based for loops
   T *begin() { return data_; }
   T *end() { return data_ + size_; }
   const T *begin() const { return data_; }

From fbef9b126403ca49999b589ba5670fbe980b7c9e Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Mon, 13 Oct 2025 14:03:59 -1000
Subject: [PATCH 47/90] revert

---
 .../components/bluetooth_proxy/bluetooth_connection.cpp   | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/esphome/components/bluetooth_proxy/bluetooth_connection.cpp b/esphome/components/bluetooth_proxy/bluetooth_connection.cpp
index 6f172b0bcf..cde82fbfb0 100644
--- a/esphome/components/bluetooth_proxy/bluetooth_connection.cpp
+++ b/esphome/components/bluetooth_proxy/bluetooth_connection.cpp
@@ -230,8 +230,8 @@ void BluetoothConnection::send_service_for_discovery_() {
     service_resp.handle = service_result.start_handle;
 
     if (total_char_count > 0) {
-      // Initialize FixedVector with exact count and process characteristics
-      service_resp.characteristics.init(total_char_count);
+      // Reserve space and process characteristics
+      service_resp.characteristics.reserve(total_char_count);
       uint16_t char_offset = 0;
       esp_gattc_char_elem_t char_result;
       while (true) {  // characteristics
@@ -275,8 +275,8 @@ void BluetoothConnection::send_service_for_discovery_() {
           continue;
         }
 
-        // Initialize FixedVector with exact count and process descriptors
-        characteristic_resp.descriptors.init(total_desc_count);
+        // Reserve space and process descriptors
+        characteristic_resp.descriptors.reserve(total_desc_count);
         uint16_t desc_offset = 0;
         esp_gattc_descr_elem_t desc_result;
         while (true) {  // descriptors

From ddf6e0a7b61ac09db7bfdafc17362cf4804b189f Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Mon, 13 Oct 2025 14:04:15 -1000
Subject: [PATCH 48/90] revert

---
 esphome/components/api/api.proto         |  4 ++--
 esphome/components/api/api_options.proto |  6 ------
 esphome/components/api/api_pb2.h         |  4 ++--
 esphome/components/api/proto.h           | 26 +++++-------------------
 4 files changed, 9 insertions(+), 31 deletions(-)

diff --git a/esphome/components/api/api.proto b/esphome/components/api/api.proto
index 9b714d00f1..87f477799d 100644
--- a/esphome/components/api/api.proto
+++ b/esphome/components/api/api.proto
@@ -1519,7 +1519,7 @@ message BluetoothGATTCharacteristic {
   repeated uint64 uuid = 1 [(fixed_array_size) = 2, (fixed_array_skip_zero) = true];
   uint32 handle = 2;
   uint32 properties = 3;
-  repeated BluetoothGATTDescriptor descriptors = 4 [(fixed_vector) = true];
+  repeated BluetoothGATTDescriptor descriptors = 4;
 
   // New field for efficient UUID (v1.12+)
   // Only one of uuid or short_uuid will be set.
@@ -1531,7 +1531,7 @@ message BluetoothGATTCharacteristic {
 message BluetoothGATTService {
   repeated uint64 uuid = 1 [(fixed_array_size) = 2, (fixed_array_skip_zero) = true];
   uint32 handle = 2;
-  repeated BluetoothGATTCharacteristic characteristics = 3 [(fixed_vector) = true];
+  repeated BluetoothGATTCharacteristic characteristics = 3;
 
   // New field for efficient UUID (v1.12+)
   // Only one of uuid or short_uuid will be set.
diff --git a/esphome/components/api/api_options.proto b/esphome/components/api/api_options.proto
index ead8ac0bbc..633f39b552 100644
--- a/esphome/components/api/api_options.proto
+++ b/esphome/components/api/api_options.proto
@@ -64,10 +64,4 @@ extend google.protobuf.FieldOptions {
     // This is typically done through methods returning const T& or special accessor
     // methods like get_options() or supported_modes_for_api_().
     optional string container_pointer = 50001;
-
-    // fixed_vector: Use FixedVector instead of std::vector for repeated fields
-    // When set, the repeated field will use FixedVector<T> which requires calling
-    // init(size) before adding elements. This eliminates std::vector template overhead
-    // and is ideal when the exact size is known before populating the array.
-    optional bool fixed_vector = 50013 [default=false];
 }
diff --git a/esphome/components/api/api_pb2.h b/esphome/components/api/api_pb2.h
index 1798458393..d9e68ece9b 100644
--- a/esphome/components/api/api_pb2.h
+++ b/esphome/components/api/api_pb2.h
@@ -1923,7 +1923,7 @@ class BluetoothGATTCharacteristic final : public ProtoMessage {
   std::array<uint64_t, 2> uuid{};
   uint32_t handle{0};
   uint32_t properties{0};
-  FixedVector<BluetoothGATTDescriptor> descriptors{};
+  std::vector<BluetoothGATTDescriptor> descriptors{};
   uint32_t short_uuid{0};
   void encode(ProtoWriteBuffer buffer) const override;
   void calculate_size(ProtoSize &size) const override;
@@ -1937,7 +1937,7 @@ class BluetoothGATTService final : public ProtoMessage {
  public:
   std::array<uint64_t, 2> uuid{};
   uint32_t handle{0};
-  FixedVector<BluetoothGATTCharacteristic> characteristics{};
+  std::vector<BluetoothGATTCharacteristic> characteristics{};
   uint32_t short_uuid{0};
   void encode(ProtoWriteBuffer buffer) const override;
   void calculate_size(ProtoSize &size) const override;
diff --git a/esphome/components/api/proto.h b/esphome/components/api/proto.h
index a6a09bf7c5..9d780692ec 100644
--- a/esphome/components/api/proto.h
+++ b/esphome/components/api/proto.h
@@ -749,29 +749,13 @@ class ProtoSize {
   template<typename MessageType>
   inline void add_repeated_message(uint32_t field_id_size, const std::vector<MessageType> &messages) {
     // Skip if the vector is empty
-    if (!messages.empty()) {
-      // Use the force version for all messages in the repeated field
-      for (const auto &message : messages) {
-        add_message_object_force(field_id_size, message);
-      }
+    if (messages.empty()) {
+      return;
     }
-  }
 
-  /**
-   * @brief Calculates and adds the sizes of all messages in a repeated field to the total message size (FixedVector
-   * version)
-   *
-   * @tparam MessageType The type of the nested messages in the FixedVector
-   * @param messages FixedVector of message objects
-   */
-  template<typename MessageType>
-  inline void add_repeated_message(uint32_t field_id_size, const FixedVector<MessageType> &messages) {
-    // Skip if the fixed vector is empty
-    if (!messages.empty()) {
-      // Use the force version for all messages in the repeated field
-      for (const auto &message : messages) {
-        add_message_object_force(field_id_size, message);
-      }
+    // Use the force version for all messages in the repeated field
+    for (const auto &message : messages) {
+      add_message_object_force(field_id_size, message);
     }
   }
 };

From d5234e335709e63eb022240c98c9c885994b247f Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Mon, 13 Oct 2025 14:04:39 -1000
Subject: [PATCH 49/90] merge

---
 esphome/components/wifi/wifi_component_esp_idf.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/esphome/components/wifi/wifi_component_esp_idf.cpp b/esphome/components/wifi/wifi_component_esp_idf.cpp
index 4c719ef4c3..e45b873e8d 100644
--- a/esphome/components/wifi/wifi_component_esp_idf.cpp
+++ b/esphome/components/wifi/wifi_component_esp_idf.cpp
@@ -763,8 +763,8 @@ void WiFiComponent::wifi_process_event_(IDFWiFiEvent *data) {
     const auto &it = data->data.sta_scan_done;
     ESP_LOGV(TAG, "Scan done: status=%" PRIu32 " number=%u scan_id=%u", it.status, it.number, it.scan_id);
 
-    this->scan_done_ = true;
     scan_result_.clear();
+    this->scan_done_ = true;
 
     if (it.status != 0) {
       // scan error

From ce46f1630859861534f91ed15e03a3ae5c335855 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Mon, 13 Oct 2025 14:05:19 -1000
Subject: [PATCH 50/90] merge

---
 esphome/components/wifi/wifi_component_esp_idf.cpp | 1 -
 1 file changed, 1 deletion(-)

diff --git a/esphome/components/wifi/wifi_component_esp_idf.cpp b/esphome/components/wifi/wifi_component_esp_idf.cpp
index e45b873e8d..951f5803a6 100644
--- a/esphome/components/wifi/wifi_component_esp_idf.cpp
+++ b/esphome/components/wifi/wifi_component_esp_idf.cpp
@@ -765,7 +765,6 @@ void WiFiComponent::wifi_process_event_(IDFWiFiEvent *data) {
 
     scan_result_.clear();
     this->scan_done_ = true;
-
     if (it.status != 0) {
       // scan error
       return;

From 7792a115c26d93b7d18cb112008457a30dfad2ea Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Mon, 13 Oct 2025 14:05:31 -1000
Subject: [PATCH 51/90] merge

---
 script/api_protobuf/api_protobuf.py | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/script/api_protobuf/api_protobuf.py b/script/api_protobuf/api_protobuf.py
index 9a55f1d136..487c187372 100755
--- a/script/api_protobuf/api_protobuf.py
+++ b/script/api_protobuf/api_protobuf.py
@@ -1415,8 +1415,6 @@ class RepeatedTypeInfo(TypeInfo):
         # Check if this is a pointer field by looking for container_pointer option
         self._container_type = get_field_opt(field, pb.container_pointer, "")
         self._use_pointer = bool(self._container_type)
-        # Check if this should use FixedVector instead of std::vector
-        self._use_fixed_vector = get_field_opt(field, pb.fixed_vector, False)
 
         # For repeated fields, we need to get the base type info
         # but we can't call create_field_type_info as it would cause recursion
@@ -1440,8 +1438,6 @@ class RepeatedTypeInfo(TypeInfo):
             if "<" in self._container_type and ">" in self._container_type:
                 return f"const {self._container_type}*"
             return f"const {self._container_type}<{self._ti.cpp_type}>*"
-        if self._use_fixed_vector:
-            return f"FixedVector<{self._ti.cpp_type}>"
         return f"std::vector<{self._ti.cpp_type}>"
 
     @property

From bb2f568f3d4971b536a6c5a59bb25bb59fc45365 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Mon, 13 Oct 2025 14:07:52 -1000
Subject: [PATCH 52/90] merge

---
 esphome/core/helpers.h | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/esphome/core/helpers.h b/esphome/core/helpers.h
index 084ad28882..6b04af3c7c 100644
--- a/esphome/core/helpers.h
+++ b/esphome/core/helpers.h
@@ -226,9 +226,6 @@ template<typename T> class FixedVector {
   // Clear the vector (reset size to 0, keep capacity)
   void clear() { size_ = 0; }
 
-  // Check if vector is empty
-  bool empty() const { return size_ == 0; }
-
   /// Add element without bounds checking
   /// Caller must ensure sufficient capacity was allocated via init()
   /// Silently ignores pushes beyond capacity (no exception or assertion)

From c9a1664398e8a4a9c8f9a3c38d5e67dadf5c6303 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Mon, 13 Oct 2025 14:08:27 -1000
Subject: [PATCH 53/90] merge

---
 esphome/core/helpers.h | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/esphome/core/helpers.h b/esphome/core/helpers.h
index 084ad28882..6b04af3c7c 100644
--- a/esphome/core/helpers.h
+++ b/esphome/core/helpers.h
@@ -226,9 +226,6 @@ template<typename T> class FixedVector {
   // Clear the vector (reset size to 0, keep capacity)
   void clear() { size_ = 0; }
 
-  // Check if vector is empty
-  bool empty() const { return size_ == 0; }
-
   /// Add element without bounds checking
   /// Caller must ensure sufficient capacity was allocated via init()
   /// Silently ignores pushes beyond capacity (no exception or assertion)

From b878aa0270c2faaedee25342d1a15b69c43dbad6 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Mon, 13 Oct 2025 14:09:44 -1000
Subject: [PATCH 54/90] fix

---
 esphome/core/helpers.h | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/esphome/core/helpers.h b/esphome/core/helpers.h
index 6b04af3c7c..a3c0447a8d 100644
--- a/esphome/core/helpers.h
+++ b/esphome/core/helpers.h
@@ -226,6 +226,14 @@ template<typename T> class FixedVector {
   // Clear the vector (reset size to 0, keep capacity)
   void clear() { size_ = 0; }
 
+  // Shrink capacity to fit current size (frees all memory)
+  void shrink_to_fit() {
+    cleanup_();
+    data_ = nullptr;
+    capacity_ = 0;
+    size_ = 0;
+  }
+
   /// Add element without bounds checking
   /// Caller must ensure sufficient capacity was allocated via init()
   /// Silently ignores pushes beyond capacity (no exception or assertion)

From de10d781259fb73b605fed83d5c14812997234b8 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Mon, 13 Oct 2025 14:10:41 -1000
Subject: [PATCH 55/90] dry

---
 esphome/core/helpers.h | 27 ++++++++++++---------------
 1 file changed, 12 insertions(+), 15 deletions(-)

diff --git a/esphome/core/helpers.h b/esphome/core/helpers.h
index a3c0447a8d..e838c82f3e 100644
--- a/esphome/core/helpers.h
+++ b/esphome/core/helpers.h
@@ -180,6 +180,13 @@ template<typename T> class FixedVector {
     }
   }
 
+  // Helper to reset pointers after cleanup
+  void reset_() {
+    data_ = nullptr;
+    capacity_ = 0;
+    size_ = 0;
+  }
+
  public:
   FixedVector() = default;
 
@@ -187,25 +194,19 @@ template<typename T> class FixedVector {
 
   // Enable move semantics for use in containers
   FixedVector(FixedVector &&other) noexcept : data_(other.data_), size_(other.size_), capacity_(other.capacity_) {
-    other.data_ = nullptr;
-    other.size_ = 0;
-    other.capacity_ = 0;
+    other.reset_();
   }
 
   FixedVector &operator=(FixedVector &&other) noexcept {
     if (this != &other) {
       // Delete our current data
-      if (data_ != nullptr) {
-        delete[] data_;
-      }
+      cleanup_();
       // Take ownership of other's data
       data_ = other.data_;
       size_ = other.size_;
       capacity_ = other.capacity_;
       // Leave other in valid empty state
-      other.data_ = nullptr;
-      other.size_ = 0;
-      other.capacity_ = 0;
+      other.reset_();
     }
     return *this;
   }
@@ -213,9 +214,7 @@ template<typename T> class FixedVector {
   // Allocate capacity - can be called multiple times to reinit
   void init(size_t n) {
     cleanup_();
-    data_ = nullptr;
-    capacity_ = 0;
-    size_ = 0;
+    reset_();
     if (n > 0) {
       // Allocate raw memory without calling constructors
       data_ = static_cast<T *>(::operator new(n * sizeof(T)));
@@ -229,9 +228,7 @@ template<typename T> class FixedVector {
   // Shrink capacity to fit current size (frees all memory)
   void shrink_to_fit() {
     cleanup_();
-    data_ = nullptr;
-    capacity_ = 0;
-    size_ = 0;
+    reset_();
   }
 
   /// Add element without bounds checking

From 453ab0adb8ec9f6da7af1d84590e1a2d309711e7 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Mon, 13 Oct 2025 14:10:56 -1000
Subject: [PATCH 56/90] backmerge

---
 esphome/core/helpers.h | 29 +++++++++++++++++------------
 1 file changed, 17 insertions(+), 12 deletions(-)

diff --git a/esphome/core/helpers.h b/esphome/core/helpers.h
index 6b04af3c7c..e838c82f3e 100644
--- a/esphome/core/helpers.h
+++ b/esphome/core/helpers.h
@@ -180,6 +180,13 @@ template<typename T> class FixedVector {
     }
   }
 
+  // Helper to reset pointers after cleanup
+  void reset_() {
+    data_ = nullptr;
+    capacity_ = 0;
+    size_ = 0;
+  }
+
  public:
   FixedVector() = default;
 
@@ -187,25 +194,19 @@ template<typename T> class FixedVector {
 
   // Enable move semantics for use in containers
   FixedVector(FixedVector &&other) noexcept : data_(other.data_), size_(other.size_), capacity_(other.capacity_) {
-    other.data_ = nullptr;
-    other.size_ = 0;
-    other.capacity_ = 0;
+    other.reset_();
   }
 
   FixedVector &operator=(FixedVector &&other) noexcept {
     if (this != &other) {
       // Delete our current data
-      if (data_ != nullptr) {
-        delete[] data_;
-      }
+      cleanup_();
       // Take ownership of other's data
       data_ = other.data_;
       size_ = other.size_;
       capacity_ = other.capacity_;
       // Leave other in valid empty state
-      other.data_ = nullptr;
-      other.size_ = 0;
-      other.capacity_ = 0;
+      other.reset_();
     }
     return *this;
   }
@@ -213,9 +214,7 @@ template<typename T> class FixedVector {
   // Allocate capacity - can be called multiple times to reinit
   void init(size_t n) {
     cleanup_();
-    data_ = nullptr;
-    capacity_ = 0;
-    size_ = 0;
+    reset_();
     if (n > 0) {
       // Allocate raw memory without calling constructors
       data_ = static_cast<T *>(::operator new(n * sizeof(T)));
@@ -226,6 +225,12 @@ template<typename T> class FixedVector {
   // Clear the vector (reset size to 0, keep capacity)
   void clear() { size_ = 0; }
 
+  // Shrink capacity to fit current size (frees all memory)
+  void shrink_to_fit() {
+    cleanup_();
+    reset_();
+  }
+
   /// Add element without bounds checking
   /// Caller must ensure sufficient capacity was allocated via init()
   /// Silently ignores pushes beyond capacity (no exception or assertion)

From 7b5a86e4df1a90f2521b283d7ec8a17c5c5e2359 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Mon, 13 Oct 2025 14:15:37 -1000
Subject: [PATCH 57/90] fixes

---
 esphome/components/wifi/wifi_component.cpp |  2 +-
 esphome/components/wifi/wifi_component.h   | 12 ++++++++++--
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/esphome/components/wifi/wifi_component.cpp b/esphome/components/wifi/wifi_component.cpp
index 3cdc034be6..8308421220 100644
--- a/esphome/components/wifi/wifi_component.cpp
+++ b/esphome/components/wifi/wifi_component.cpp
@@ -554,7 +554,7 @@ void WiFiComponent::start_scanning() {
 // Using insertion sort instead of std::stable_sort saves flash memory
 // by avoiding template instantiations (std::rotate, std::stable_sort, lambdas)
 // IMPORTANT: This sort is stable (preserves relative order of equal elements)
-static void insertion_sort_scan_results(FixedVector<WiFiScanResult> &results) {
+template<typename VectorType> static void insertion_sort_scan_results(VectorType &results) {
   const size_t size = results.size();
   for (size_t i = 1; i < size; i++) {
     // Make a copy to avoid issues with move semantics during comparison
diff --git a/esphome/components/wifi/wifi_component.h b/esphome/components/wifi/wifi_component.h
index e1c3d6df88..bbb4649027 100644
--- a/esphome/components/wifi/wifi_component.h
+++ b/esphome/components/wifi/wifi_component.h
@@ -121,6 +121,14 @@ struct EAPAuth {
 
 using bssid_t = std::array<uint8_t, 6>;
 
+// Use std::vector for RP2040 since scan count is unknown (callback-based)
+// Use FixedVector for other platforms where count is queried first
+#ifdef USE_RP2040
+template<typename T> using wifi_scan_vector_t = std::vector<T>;
+#else
+template<typename T> using wifi_scan_vector_t = FixedVector<T>;
+#endif
+
 class WiFiAP {
  public:
   void set_ssid(const std::string &ssid);
@@ -278,7 +286,7 @@ class WiFiComponent : public Component {
   std::string get_use_address() const;
   void set_use_address(const std::string &use_address);
 
-  const FixedVector<WiFiScanResult> &get_scan_result() const { return scan_result_; }
+  const wifi_scan_vector_t<WiFiScanResult> &get_scan_result() const { return scan_result_; }
 
   network::IPAddress wifi_soft_ap_ip();
 
@@ -385,7 +393,7 @@ class WiFiComponent : public Component {
   std::string use_address_;
   std::vector<WiFiAP> sta_;
   std::vector<WiFiSTAPriority> sta_priorities_;
-  FixedVector<WiFiScanResult> scan_result_;
+  wifi_scan_vector_t<WiFiScanResult> scan_result_;
   WiFiAP selected_ap_;
   WiFiAP ap_;
   optional<float> output_power_;

From 10724f411b04fc3a8e40c6a8c075e0af2e0c2326 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Mon, 13 Oct 2025 14:32:17 -1000
Subject: [PATCH 58/90] [network] Optimize get_use_address() to return const
 reference instead of copy

---
 esphome/components/ethernet/ethernet_component.cpp | 11 +++--------
 esphome/components/ethernet/ethernet_component.h   |  2 +-
 esphome/components/network/util.cpp                |  7 +++++--
 esphome/components/network/util.h                  |  2 +-
 esphome/components/wifi/wifi_component.cpp         | 11 +++--------
 esphome/components/wifi/wifi_component.h           |  2 +-
 6 files changed, 14 insertions(+), 21 deletions(-)

diff --git a/esphome/components/ethernet/ethernet_component.cpp b/esphome/components/ethernet/ethernet_component.cpp
index 13adab8815..24b6e8154b 100644
--- a/esphome/components/ethernet/ethernet_component.cpp
+++ b/esphome/components/ethernet/ethernet_component.cpp
@@ -689,14 +689,9 @@ void EthernetComponent::add_phy_register(PHYRegister register_value) { this->phy
 void EthernetComponent::set_type(EthernetType type) { this->type_ = type; }
 void EthernetComponent::set_manual_ip(const ManualIP &manual_ip) { this->manual_ip_ = manual_ip; }
 
-std::string EthernetComponent::get_use_address() const {
-  if (this->use_address_.empty()) {
-    // ".local" suffix length for mDNS hostnames
-    constexpr size_t mdns_local_suffix_len = 5;
-    return make_name_with_suffix(App.get_name(), '.', "local", mdns_local_suffix_len);
-  }
-  return this->use_address_;
-}
+// set_use_address() is guaranteed to be called during component setup by Python code generation,
+// so use_address_ will always be valid when get_use_address() is called - no fallback needed.
+const std::string &EthernetComponent::get_use_address() const { return this->use_address_; }
 
 void EthernetComponent::set_use_address(const std::string &use_address) { this->use_address_ = use_address; }
 
diff --git a/esphome/components/ethernet/ethernet_component.h b/esphome/components/ethernet/ethernet_component.h
index 6b4e342df5..d5dda3e3ae 100644
--- a/esphome/components/ethernet/ethernet_component.h
+++ b/esphome/components/ethernet/ethernet_component.h
@@ -88,7 +88,7 @@ class EthernetComponent : public Component {
 
   network::IPAddresses get_ip_addresses();
   network::IPAddress get_dns_address(uint8_t num);
-  std::string get_use_address() const;
+  const std::string &get_use_address() const;
   void set_use_address(const std::string &use_address);
   void get_eth_mac_address_raw(uint8_t *mac);
   std::string get_eth_mac_address_pretty();
diff --git a/esphome/components/network/util.cpp b/esphome/components/network/util.cpp
index bf76aefc30..0f28e2d3fb 100644
--- a/esphome/components/network/util.cpp
+++ b/esphome/components/network/util.cpp
@@ -85,7 +85,7 @@ network::IPAddresses get_ip_addresses() {
   return {};
 }
 
-std::string get_use_address() {
+const std::string &get_use_address() {
 #ifdef USE_ETHERNET
   if (ethernet::global_eth_component != nullptr)
     return ethernet::global_eth_component->get_use_address();
@@ -100,7 +100,10 @@ std::string get_use_address() {
   if (wifi::global_wifi_component != nullptr)
     return wifi::global_wifi_component->get_use_address();
 #endif
-  return "";
+#if !defined(USE_ETHERNET) && !defined(USE_MODEM) && !defined(USE_WIFI)
+  static const std::string empty;
+  return empty;
+#endif
 }
 
 }  // namespace network
diff --git a/esphome/components/network/util.h b/esphome/components/network/util.h
index b518696e68..b4a92f8bee 100644
--- a/esphome/components/network/util.h
+++ b/esphome/components/network/util.h
@@ -12,7 +12,7 @@ bool is_connected();
 /// Return whether the network is disabled (only wifi for now)
 bool is_disabled();
 /// Get the active network hostname
-std::string get_use_address();
+const std::string &get_use_address();
 IPAddresses get_ip_addresses();
 
 }  // namespace network
diff --git a/esphome/components/wifi/wifi_component.cpp b/esphome/components/wifi/wifi_component.cpp
index 0f9f879181..aa197b36e5 100644
--- a/esphome/components/wifi/wifi_component.cpp
+++ b/esphome/components/wifi/wifi_component.cpp
@@ -265,14 +265,9 @@ network::IPAddress WiFiComponent::get_dns_address(int num) {
     return this->wifi_dns_ip_(num);
   return {};
 }
-std::string WiFiComponent::get_use_address() const {
-  if (this->use_address_.empty()) {
-    // ".local" suffix length for mDNS hostnames
-    constexpr size_t mdns_local_suffix_len = 5;
-    return make_name_with_suffix(App.get_name(), '.', "local", mdns_local_suffix_len);
-  }
-  return this->use_address_;
-}
+// set_use_address() is guaranteed to be called during component setup by Python code generation,
+// so use_address_ will always be valid when get_use_address() is called - no fallback needed.
+const std::string &WiFiComponent::get_use_address() const { return this->use_address_; }
 void WiFiComponent::set_use_address(const std::string &use_address) { this->use_address_ = use_address; }
 
 #ifdef USE_WIFI_AP
diff --git a/esphome/components/wifi/wifi_component.h b/esphome/components/wifi/wifi_component.h
index ee62ec1a69..0e0f89d2c1 100644
--- a/esphome/components/wifi/wifi_component.h
+++ b/esphome/components/wifi/wifi_component.h
@@ -275,7 +275,7 @@ class WiFiComponent : public Component {
 
   network::IPAddress get_dns_address(int num);
   network::IPAddresses get_ip_addresses();
-  std::string get_use_address() const;
+  const std::string &get_use_address() const;
   void set_use_address(const std::string &use_address);
 
   const std::vector<WiFiScanResult> &get_scan_result() const { return scan_result_; }

From 2881f32b08549f34c09cfe37b14e71bc984a6008 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Mon, 13 Oct 2025 14:37:10 -1000
Subject: [PATCH 59/90] [network] Optimize get_use_address() to return const
 reference instead of copy

---
 esphome/components/network/util.cpp | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/esphome/components/network/util.cpp b/esphome/components/network/util.cpp
index 0f28e2d3fb..12939f8f84 100644
--- a/esphome/components/network/util.cpp
+++ b/esphome/components/network/util.cpp
@@ -86,21 +86,21 @@ network::IPAddresses get_ip_addresses() {
 }
 
 const std::string &get_use_address() {
+  // Global component pointers are guaranteed to be set by component constructors when USE_* is defined
 #ifdef USE_ETHERNET
-  if (ethernet::global_eth_component != nullptr)
-    return ethernet::global_eth_component->get_use_address();
+  return ethernet::global_eth_component->get_use_address();
 #endif
 
 #ifdef USE_MODEM
-  if (modem::global_modem_component != nullptr)
-    return modem::global_modem_component->get_use_address();
+  return modem::global_modem_component->get_use_address();
 #endif
 
 #ifdef USE_WIFI
-  if (wifi::global_wifi_component != nullptr)
-    return wifi::global_wifi_component->get_use_address();
+  return wifi::global_wifi_component->get_use_address();
 #endif
+
 #if !defined(USE_ETHERNET) && !defined(USE_MODEM) && !defined(USE_WIFI)
+  // Fallback when no network component is defined (shouldn't happen with USE_NETWORK defined)
   static const std::string empty;
   return empty;
 #endif

From fa830cfd399384979992b21bf0d225c1a66e6793 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Mon, 13 Oct 2025 14:50:55 -1000
Subject: [PATCH 60/90] fix

---
 esphome/components/improv_serial/improv_serial_component.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/esphome/components/improv_serial/improv_serial_component.cpp b/esphome/components/improv_serial/improv_serial_component.cpp
index 528a155a7f..28245dcfdf 100644
--- a/esphome/components/improv_serial/improv_serial_component.cpp
+++ b/esphome/components/improv_serial/improv_serial_component.cpp
@@ -218,7 +218,7 @@ bool ImprovSerialComponent::parse_improv_payload_(improv::ImprovCommand &command
     }
     case improv::GET_WIFI_NETWORKS: {
       std::vector<std::string> networks;
-      auto results = wifi::global_wifi_component->get_scan_result();
+      const auto &results = wifi::global_wifi_component->get_scan_result();
       for (auto &scan : results) {
         if (scan.get_is_hidden())
           continue;

From e17cdffc78cb879bb7eac15e0e2b11ac66d8118b Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Mon, 13 Oct 2025 15:04:40 -1000
Subject: [PATCH 61/90] merge

---
 esphome/core/helpers.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/esphome/core/helpers.h b/esphome/core/helpers.h
index e838c82f3e..4dcd44a574 100644
--- a/esphome/core/helpers.h
+++ b/esphome/core/helpers.h
@@ -217,6 +217,8 @@ template<typename T> class FixedVector {
     reset_();
     if (n > 0) {
       // Allocate raw memory without calling constructors
+      // sizeof(T) is correct here - when T is a pointer type, we want the pointer size
+      // NOLINTNEXTLINE(bugprone-sizeof-expression)
       data_ = static_cast<T *>(::operator new(n * sizeof(T)));
       capacity_ = n;
     }

From d5ba16f13a57add5db95a600e8bb6d09a1493236 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Mon, 13 Oct 2025 15:22:52 -1000
Subject: [PATCH 62/90] merge

---
 esphome/core/helpers.h | 39 +++++++++++++++++++++++++++++++--------
 1 file changed, 31 insertions(+), 8 deletions(-)

diff --git a/esphome/core/helpers.h b/esphome/core/helpers.h
index 4dcd44a574..6d7ae564e8 100644
--- a/esphome/core/helpers.h
+++ b/esphome/core/helpers.h
@@ -224,8 +224,14 @@ template<typename T> class FixedVector {
     }
   }
 
-  // Clear the vector (reset size to 0, keep capacity)
-  void clear() { size_ = 0; }
+  // Clear the vector (destroy all elements, reset size to 0, keep capacity)
+  void clear() {
+    // Manually destroy all elements
+    for (size_t i = 0; i < size_; i++) {
+      data_[i].~T();
+    }
+    size_ = 0;
+  }
 
   // Shrink capacity to fit current size (frees all memory)
   void shrink_to_fit() {
@@ -244,17 +250,34 @@ template<typename T> class FixedVector {
     }
   }
 
-  /// Construct element in place and return reference
+  /// Add element by move without bounds checking
   /// Caller must ensure sufficient capacity was allocated via init()
-  T &emplace_back() {
+  /// Silently ignores pushes beyond capacity (no exception or assertion)
+  void push_back(T &&value) {
     if (size_ < capacity_) {
-      return data_[size_++];
+      // Use placement new to move-construct the object in pre-allocated memory
+      new (&data_[size_]) T(std::move(value));
+      size_++;
     }
-    // Should never happen with proper init() - return last element to avoid crash
-    return data_[capacity_ - 1];
   }
 
-  /// Access last element
+  /// Emplace element without bounds checking - constructs in-place
+  /// Caller must ensure sufficient capacity was allocated via init()
+  /// Returns reference to the newly constructed element
+  /// Silently ignores emplaces beyond capacity (returns reference to last element)
+  T &emplace_back() {
+    if (size_ < capacity_) {
+      // Use placement new to default-construct the object in pre-allocated memory
+      new (&data_[size_]) T();
+      size_++;
+      return data_[size_ - 1];
+    }
+    // Beyond capacity - return reference to last element to avoid crash
+    return data_[size_ - 1];
+  }
+
+  /// Access last element (no bounds checking - matches std::vector behavior)
+  /// Caller must ensure vector is not empty (size() > 0)
   T &back() { return data_[size_ - 1]; }
   const T &back() const { return data_[size_ - 1]; }
 

From 9775274007f13edc65f6a3230daa464abbf7fc64 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Mon, 13 Oct 2025 15:25:47 -1000
Subject: [PATCH 63/90] preen

---
 esphome/core/helpers.h | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/esphome/core/helpers.h b/esphome/core/helpers.h
index 6d7ae564e8..349ed663ad 100644
--- a/esphome/core/helpers.h
+++ b/esphome/core/helpers.h
@@ -168,13 +168,17 @@ template<typename T> class FixedVector {
   size_t size_{0};
   size_t capacity_{0};
 
+  // Helper to destroy all elements without freeing memory
+  void destroy_elements_() {
+    for (size_t i = 0; i < size_; i++) {
+      data_[i].~T();
+    }
+  }
+
   // Helper to destroy elements and free memory
   void cleanup_() {
     if (data_ != nullptr) {
-      // Manually destroy all elements
-      for (size_t i = 0; i < size_; i++) {
-        data_[i].~T();
-      }
+      destroy_elements_();
       // Free raw memory
       ::operator delete(data_);
     }
@@ -226,10 +230,7 @@ template<typename T> class FixedVector {
 
   // Clear the vector (destroy all elements, reset size to 0, keep capacity)
   void clear() {
-    // Manually destroy all elements
-    for (size_t i = 0; i < size_; i++) {
-      data_[i].~T();
-    }
+    destroy_elements_();
     size_ = 0;
   }
 

From 2626a851fbf1e7feb85c1661373941359bd72f08 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Mon, 13 Oct 2025 15:30:18 -1000
Subject: [PATCH 64/90] cleanup

---
 esphome/core/helpers.h | 21 ++++++++++-----------
 1 file changed, 10 insertions(+), 11 deletions(-)

diff --git a/esphome/core/helpers.h b/esphome/core/helpers.h
index 349ed663ad..3ca62a68cb 100644
--- a/esphome/core/helpers.h
+++ b/esphome/core/helpers.h
@@ -170,8 +170,11 @@ template<typename T> class FixedVector {
 
   // Helper to destroy all elements without freeing memory
   void destroy_elements_() {
-    for (size_t i = 0; i < size_; i++) {
-      data_[i].~T();
+    // Only call destructors for non-trivially destructible types
+    if constexpr (!std::is_trivially_destructible<T>::value) {
+      for (size_t i = 0; i < size_; i++) {
+        data_[i].~T();
+      }
     }
   }
 
@@ -221,7 +224,7 @@ template<typename T> class FixedVector {
     reset_();
     if (n > 0) {
       // Allocate raw memory without calling constructors
-      // sizeof(T) is correct here - when T is a pointer type, we want the pointer size
+      // sizeof(T) is correct here for any type T (value types, pointers, etc.)
       // NOLINTNEXTLINE(bugprone-sizeof-expression)
       data_ = static_cast<T *>(::operator new(n * sizeof(T)));
       capacity_ = n;
@@ -265,15 +268,11 @@ template<typename T> class FixedVector {
   /// Emplace element without bounds checking - constructs in-place
   /// Caller must ensure sufficient capacity was allocated via init()
   /// Returns reference to the newly constructed element
-  /// Silently ignores emplaces beyond capacity (returns reference to last element)
+  /// NOTE: Caller MUST ensure size_ < capacity_ before calling
   T &emplace_back() {
-    if (size_ < capacity_) {
-      // Use placement new to default-construct the object in pre-allocated memory
-      new (&data_[size_]) T();
-      size_++;
-      return data_[size_ - 1];
-    }
-    // Beyond capacity - return reference to last element to avoid crash
+    // Use placement new to default-construct the object in pre-allocated memory
+    new (&data_[size_]) T();
+    size_++;
     return data_[size_ - 1];
   }
 

From 6b8d5be528f77bb5e0f5e17a2acec1a35594d8ab Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Mon, 13 Oct 2025 15:41:17 -1000
Subject: [PATCH 65/90] Update esphome/components/network/util.cpp

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
---
 esphome/components/network/util.cpp | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/esphome/components/network/util.cpp b/esphome/components/network/util.cpp
index 12939f8f84..d29bf8e6bd 100644
--- a/esphome/components/network/util.cpp
+++ b/esphome/components/network/util.cpp
@@ -100,9 +100,7 @@ const std::string &get_use_address() {
 #endif
 
 #if !defined(USE_ETHERNET) && !defined(USE_MODEM) && !defined(USE_WIFI)
-  // Fallback when no network component is defined (shouldn't happen with USE_NETWORK defined)
-  static const std::string empty;
-  return empty;
+  static_assert(false, "At least one of USE_ETHERNET, USE_MODEM, or USE_WIFI must be defined when USE_NETWORK is set.");
 #endif
 }
 

From c5076e69f0955567f406692ee29ed5503e25c0d0 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Mon, 13 Oct 2025 15:52:00 -1000
Subject: [PATCH 66/90] host platform

---
 esphome/components/network/util.cpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/esphome/components/network/util.cpp b/esphome/components/network/util.cpp
index d29bf8e6bd..27ad9448a4 100644
--- a/esphome/components/network/util.cpp
+++ b/esphome/components/network/util.cpp
@@ -100,7 +100,9 @@ const std::string &get_use_address() {
 #endif
 
 #if !defined(USE_ETHERNET) && !defined(USE_MODEM) && !defined(USE_WIFI)
-  static_assert(false, "At least one of USE_ETHERNET, USE_MODEM, or USE_WIFI must be defined when USE_NETWORK is set.");
+  // Fallback when no network component is defined (e.g., host platform)
+  static const std::string empty;
+  return empty;
 #endif
 }
 

From 5c30c1b6916920a406157aeff74d9ad60b981850 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Mon, 13 Oct 2025 17:49:07 -1000
Subject: [PATCH 67/90] core.data

---
 esphome/components/wifi/__init__.py | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/esphome/components/wifi/__init__.py b/esphome/components/wifi/__init__.py
index ae85e40357..ad5698519b 100644
--- a/esphome/components/wifi/__init__.py
+++ b/esphome/components/wifi/__init__.py
@@ -470,7 +470,7 @@ async def wifi_disable_to_code(config, action_id, template_arg, args):
     return cg.new_Pvariable(action_id, template_arg)
 
 
-_FLAGS = {"keep_scan_results": False}
+KEEP_SCAN_RESULTS_KEY = "wifi_keep_scan_results"
 
 
 def request_wifi_scan_results():
@@ -480,13 +480,13 @@ def request_wifi_scan_results():
     call this function during their code generation. This prevents the WiFi component from
     freeing scan result memory after successful connection.
     """
-    _FLAGS["keep_scan_results"] = True
+    CORE.data[KEEP_SCAN_RESULTS_KEY] = True
 
 
 @coroutine_with_priority(CoroPriority.FINAL)
 async def final_step():
     """Final code generation step to configure scan result retention."""
-    if _FLAGS["keep_scan_results"]:
+    if CORE.data.get(KEEP_SCAN_RESULTS_KEY, False):
         cg.add(
             cg.RawExpression("wifi::global_wifi_component->set_keep_scan_results(true)")
         )

From 5bdd6dac9721307b9b3636122fb63a0353b91564 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Mon, 13 Oct 2025 18:02:28 -1000
Subject: [PATCH 68/90] [esp32_ble_tracker] Refactor to use CORE.data instead
 of module-level globals

---
 .../components/esp32_ble_tracker/__init__.py  | 50 ++++++++++++-------
 1 file changed, 32 insertions(+), 18 deletions(-)

diff --git a/esphome/components/esp32_ble_tracker/__init__.py b/esphome/components/esp32_ble_tracker/__init__.py
index 8c7f3e3930..d9963d7391 100644
--- a/esphome/components/esp32_ble_tracker/__init__.py
+++ b/esphome/components/esp32_ble_tracker/__init__.py
@@ -60,11 +60,21 @@ class RegistrationCounts:
     clients: int = 0
 
 
-# Set to track which features are needed by components
-_required_features: set[BLEFeatures] = set()
+# CORE.data keys for state management
+ESP32_BLE_TRACKER_REQUIRED_FEATURES_KEY = "esp32_ble_tracker_required_features"
+ESP32_BLE_TRACKER_REGISTRATION_COUNTS_KEY = "esp32_ble_tracker_registration_counts"
 
-# Track registration counts for StaticVector sizing
-_registration_counts = RegistrationCounts()
+
+def _get_required_features() -> set[BLEFeatures]:
+    """Get the set of required BLE features from CORE.data."""
+    return CORE.data.setdefault(ESP32_BLE_TRACKER_REQUIRED_FEATURES_KEY, set())
+
+
+def _get_registration_counts() -> RegistrationCounts:
+    """Get the registration counts from CORE.data."""
+    return CORE.data.setdefault(
+        ESP32_BLE_TRACKER_REGISTRATION_COUNTS_KEY, RegistrationCounts()
+    )
 
 
 def register_ble_features(features: set[BLEFeatures]) -> None:
@@ -73,7 +83,7 @@ def register_ble_features(features: set[BLEFeatures]) -> None:
     Args:
         features: Set of BLEFeatures enum members
     """
-    _required_features.update(features)
+    _get_required_features().update(features)
 
 
 esp32_ble_tracker_ns = cg.esphome_ns.namespace("esp32_ble_tracker")
@@ -267,15 +277,17 @@ async def to_code(config):
     ):
         register_ble_features({BLEFeatures.ESP_BT_DEVICE})
 
+    registration_counts = _get_registration_counts()
+
     for conf in config.get(CONF_ON_BLE_ADVERTISE, []):
-        _registration_counts.listeners += 1
+        registration_counts.listeners += 1
         trigger = cg.new_Pvariable(conf[CONF_TRIGGER_ID], var)
         if CONF_MAC_ADDRESS in conf:
             addr_list = [it.as_hex for it in conf[CONF_MAC_ADDRESS]]
             cg.add(trigger.set_addresses(addr_list))
         await automation.build_automation(trigger, [(ESPBTDeviceConstRef, "x")], conf)
     for conf in config.get(CONF_ON_BLE_SERVICE_DATA_ADVERTISE, []):
-        _registration_counts.listeners += 1
+        registration_counts.listeners += 1
         trigger = cg.new_Pvariable(conf[CONF_TRIGGER_ID], var)
         if len(conf[CONF_SERVICE_UUID]) == len(bt_uuid16_format):
             cg.add(trigger.set_service_uuid16(as_hex(conf[CONF_SERVICE_UUID])))
@@ -288,7 +300,7 @@ async def to_code(config):
             cg.add(trigger.set_address(conf[CONF_MAC_ADDRESS].as_hex))
         await automation.build_automation(trigger, [(adv_data_t_const_ref, "x")], conf)
     for conf in config.get(CONF_ON_BLE_MANUFACTURER_DATA_ADVERTISE, []):
-        _registration_counts.listeners += 1
+        registration_counts.listeners += 1
         trigger = cg.new_Pvariable(conf[CONF_TRIGGER_ID], var)
         if len(conf[CONF_MANUFACTURER_ID]) == len(bt_uuid16_format):
             cg.add(trigger.set_manufacturer_uuid16(as_hex(conf[CONF_MANUFACTURER_ID])))
@@ -301,7 +313,7 @@ async def to_code(config):
             cg.add(trigger.set_address(conf[CONF_MAC_ADDRESS].as_hex))
         await automation.build_automation(trigger, [(adv_data_t_const_ref, "x")], conf)
     for conf in config.get(CONF_ON_SCAN_END, []):
-        _registration_counts.listeners += 1
+        registration_counts.listeners += 1
         trigger = cg.new_Pvariable(conf[CONF_TRIGGER_ID], var)
         await automation.build_automation(trigger, [], conf)
 
@@ -331,19 +343,21 @@ async def to_code(config):
 @coroutine_with_priority(CoroPriority.FINAL)
 async def _add_ble_features():
     # Add feature-specific defines based on what's needed
-    if BLEFeatures.ESP_BT_DEVICE in _required_features:
+    required_features = _get_required_features()
+    if BLEFeatures.ESP_BT_DEVICE in required_features:
         cg.add_define("USE_ESP32_BLE_DEVICE")
         cg.add_define("USE_ESP32_BLE_UUID")
 
     # Add defines for StaticVector sizing based on registration counts
     # Only define if count > 0 to avoid allocating unnecessary memory
-    if _registration_counts.listeners > 0:
+    registration_counts = _get_registration_counts()
+    if registration_counts.listeners > 0:
         cg.add_define(
-            "ESPHOME_ESP32_BLE_TRACKER_LISTENER_COUNT", _registration_counts.listeners
+            "ESPHOME_ESP32_BLE_TRACKER_LISTENER_COUNT", registration_counts.listeners
         )
-    if _registration_counts.clients > 0:
+    if registration_counts.clients > 0:
         cg.add_define(
-            "ESPHOME_ESP32_BLE_TRACKER_CLIENT_COUNT", _registration_counts.clients
+            "ESPHOME_ESP32_BLE_TRACKER_CLIENT_COUNT", registration_counts.clients
         )
 
 
@@ -395,7 +409,7 @@ async def register_ble_device(
     var: cg.SafeExpType, config: ConfigType
 ) -> cg.SafeExpType:
     register_ble_features({BLEFeatures.ESP_BT_DEVICE})
-    _registration_counts.listeners += 1
+    _get_registration_counts().listeners += 1
     paren = await cg.get_variable(config[CONF_ESP32_BLE_ID])
     cg.add(paren.register_listener(var))
     return var
@@ -403,7 +417,7 @@ async def register_ble_device(
 
 async def register_client(var: cg.SafeExpType, config: ConfigType) -> cg.SafeExpType:
     register_ble_features({BLEFeatures.ESP_BT_DEVICE})
-    _registration_counts.clients += 1
+    _get_registration_counts().clients += 1
     paren = await cg.get_variable(config[CONF_ESP32_BLE_ID])
     cg.add(paren.register_client(var))
     return var
@@ -417,7 +431,7 @@ async def register_raw_ble_device(
     This does NOT register the ESP_BT_DEVICE feature, meaning ESPBTDevice
     will not be compiled in if this is the only registration method used.
     """
-    _registration_counts.listeners += 1
+    _get_registration_counts().listeners += 1
     paren = await cg.get_variable(config[CONF_ESP32_BLE_ID])
     cg.add(paren.register_listener(var))
     return var
@@ -431,7 +445,7 @@ async def register_raw_client(
     This does NOT register the ESP_BT_DEVICE feature, meaning ESPBTDevice
     will not be compiled in if this is the only registration method used.
     """
-    _registration_counts.clients += 1
+    _get_registration_counts().clients += 1
     paren = await cg.get_variable(config[CONF_ESP32_BLE_ID])
     cg.add(paren.register_client(var))
     return var

From dd0699305e1d4a68228941780b6e1bfab92fc217 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Mon, 13 Oct 2025 18:08:52 -1000
Subject: [PATCH 69/90] [esp32_ble] Refactor to use CORE.data instead of
 module-level globals

---
 esphome/components/esp32_ble/__init__.py | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/esphome/components/esp32_ble/__init__.py b/esphome/components/esp32_ble/__init__.py
index 1c142ca7bd..4e001b35c6 100644
--- a/esphome/components/esp32_ble/__init__.py
+++ b/esphome/components/esp32_ble/__init__.py
@@ -107,8 +107,13 @@ class BTLoggers(Enum):
     """ESP32 WiFi provisioning over Bluetooth"""
 
 
-# Set to track which loggers are needed by components
-_required_loggers: set[BTLoggers] = set()
+# Key for storing required loggers in CORE.data
+ESP32_BLE_REQUIRED_LOGGERS_KEY = "esp32_ble_required_loggers"
+
+
+def _get_required_loggers() -> set[BTLoggers]:
+    """Get the set of required Bluetooth loggers from CORE.data."""
+    return CORE.data.setdefault(ESP32_BLE_REQUIRED_LOGGERS_KEY, set())
 
 
 def register_bt_logger(*loggers: BTLoggers) -> None:
@@ -117,12 +122,13 @@ def register_bt_logger(*loggers: BTLoggers) -> None:
     Args:
         *loggers: One or more BTLoggers enum members
     """
+    required_loggers = _get_required_loggers()
     for logger in loggers:
         if not isinstance(logger, BTLoggers):
             raise TypeError(
                 f"Logger must be a BTLoggers enum member, got {type(logger)}"
             )
-        _required_loggers.add(logger)
+        required_loggers.add(logger)
 
 
 CONF_BLE_ID = "ble_id"
@@ -396,8 +402,9 @@ async def to_code(config):
     # Apply logger settings if log disabling is enabled
     if config.get(CONF_DISABLE_BT_LOGS, False):
         # Disable all Bluetooth loggers that are not required
+        required_loggers = _get_required_loggers()
         for logger in BTLoggers:
-            if logger not in _required_loggers:
+            if logger not in required_loggers:
                 add_idf_sdkconfig_option(f"{logger.value}_NONE", True)
 
     # Set BLE connection establishment timeout to match aioesphomeapi/bleak-retry-connector

From 18d5fd160a90f4536009a31b37a7d36e7de1fdf5 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Mon, 13 Oct 2025 18:11:34 -1000
Subject: [PATCH 70/90] [i2s_audio] Refactor to use CORE.data instead of
 module-level globals

---
 esphome/components/i2s_audio/__init__.py | 24 +++++++++++++++++-------
 1 file changed, 17 insertions(+), 7 deletions(-)

diff --git a/esphome/components/i2s_audio/__init__.py b/esphome/components/i2s_audio/__init__.py
index 8ceff26d84..907429ee0e 100644
--- a/esphome/components/i2s_audio/__init__.py
+++ b/esphome/components/i2s_audio/__init__.py
@@ -143,7 +143,18 @@ def validate_mclk_divisible_by_3(config):
     return config
 
 
-_use_legacy_driver = None
+# Key for storing legacy driver setting in CORE.data
+I2S_USE_LEGACY_DRIVER_KEY = "i2s_use_legacy_driver"
+
+
+def _get_use_legacy_driver():
+    """Get the legacy driver setting from CORE.data."""
+    return CORE.data.get(I2S_USE_LEGACY_DRIVER_KEY)
+
+
+def _set_use_legacy_driver(value: bool) -> None:
+    """Set the legacy driver setting in CORE.data."""
+    CORE.data[I2S_USE_LEGACY_DRIVER_KEY] = value
 
 
 def i2s_audio_component_schema(
@@ -209,17 +220,15 @@ async def register_i2s_audio_component(var, config):
 
 
 def validate_use_legacy(value):
-    global _use_legacy_driver  # noqa: PLW0603
     if CONF_USE_LEGACY in value:
-        if (_use_legacy_driver is not None) and (
-            _use_legacy_driver != value[CONF_USE_LEGACY]
-        ):
+        existing_value = _get_use_legacy_driver()
+        if (existing_value is not None) and (existing_value != value[CONF_USE_LEGACY]):
             raise cv.Invalid(
                 f"All i2s_audio components must set {CONF_USE_LEGACY} to the same value."
             )
         if (not value[CONF_USE_LEGACY]) and (CORE.using_arduino):
             raise cv.Invalid("Arduino supports only the legacy i2s driver")
-        _use_legacy_driver = value[CONF_USE_LEGACY]
+        _set_use_legacy_driver(value[CONF_USE_LEGACY])
     return value
 
 
@@ -249,7 +258,8 @@ def _final_validate(_):
 
 
 def use_legacy():
-    return not (CORE.using_esp_idf and not _use_legacy_driver)
+    legacy_driver = _get_use_legacy_driver()
+    return not (CORE.using_esp_idf and not legacy_driver)
 
 
 FINAL_VALIDATE_SCHEMA = _final_validate

From 0f43f4cbbf0e7b5ce38436cbc6ee17454aa3ae8d Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Mon, 13 Oct 2025 18:26:45 -1000
Subject: [PATCH 71/90] [docs] Add embedded systems optimization and state
 management best practices to CLAUDE.md

---
 .ai/instructions.md | 64 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 64 insertions(+)

diff --git a/.ai/instructions.md b/.ai/instructions.md
index d2e173472a..ab382c61e8 100644
--- a/.ai/instructions.md
+++ b/.ai/instructions.md
@@ -221,6 +221,70 @@ This document provides essential context for AI models interacting with this pro
     *   **Component Development:** Keep dependencies minimal, provide clear error messages, and write comprehensive docstrings and tests.
     *   **Code Generation:** Generate minimal and efficient C++ code. Validate all user inputs thoroughly. Support multiple platform variations.
     *   **Configuration Design:** Aim for simplicity with sensible defaults, while allowing for advanced customization.
+    *   **Embedded Systems Optimization:** ESPHome targets resource-constrained microcontrollers. Be mindful of flash size and RAM usage.
+
+        **STL Container Guidelines:**
+
+        ESPHome runs on embedded systems with limited resources. Choose containers carefully:
+
+        1. **Compile-time-known sizes:** Use `std::array` instead of `std::vector` when size is known at compile time.
+           ```cpp
+           // Bad - generates STL realloc code
+           std::vector<int> values;
+
+           // Good - no dynamic allocation
+           std::array<int, MAX_VALUES> values;
+           ```
+           Use `cg.add_define("MAX_VALUES", count)` to set the size from Python configuration.
+
+           **For byte buffers:** Avoid `std::vector<uint8_t>` unless the buffer needs to grow. Use `std::unique_ptr<uint8_t[]>` instead.
+           ```cpp
+           // Bad - STL overhead for simple byte buffer
+           std::vector<uint8_t> buffer;
+           buffer.resize(256);
+
+           // Good - minimal overhead, single allocation
+           std::unique_ptr<uint8_t[]> buffer = std::make_unique<uint8_t[]>(256);
+           // Or if size is constant:
+           std::array<uint8_t, 256> buffer;
+           ```
+
+        2. **Small datasets (1-16 elements):** Use `std::vector` or `std::array` with simple structs instead of `std::map`/`std::set`/`std::unordered_map`.
+           ```cpp
+           // Bad - 2KB+ overhead for red-black tree/hash table
+           std::map<std::string, int> small_lookup;
+           std::unordered_map<int, std::string> tiny_map;
+
+           // Good - simple struct with linear search (std::vector is fine)
+           struct LookupEntry {
+             const char *key;
+             int value;
+           };
+           std::vector<LookupEntry> small_lookup = {
+             {"key1", 10},
+             {"key2", 20},
+             {"key3", 30},
+           };
+           // Or std::array if size is compile-time constant:
+           // std::array<LookupEntry, 3> small_lookup = {{ ... }};
+           ```
+           Linear search on small datasets (1-16 elements) is faster than hashing/tree overhead. `std::vector` with simple structs is perfectly fine - it's the heavy containers (`map`, `set`, `unordered_map`) that should be avoided for small datasets.
+
+        3. **Detection:** Look for these patterns in compiler output:
+           - Large code sections with STL symbols (vector, map, set)
+           - `alloc`, `realloc`, `dealloc` in symbol names
+           - Red-black tree code (`rb_tree`, `_Rb_tree`)
+           - Hash table infrastructure (`unordered_map`, `hash`)
+
+        **When to optimize:**
+        - Core components (API, network, logger)
+        - Widely-used components (mdns, wifi, ble)
+        - Components causing flash size complaints
+
+        **When not to optimize:**
+        - Single-use niche components
+        - Code where readability matters more than bytes
+        - Already using appropriate containers
 
 *   **Security:** Be mindful of security when making changes to the API, web server, or any other network-related code. Do not hardcode secrets or keys.
 

From 541c697a42e5ff46434a3f4fdcf4e8e1cb6c6777 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Mon, 13 Oct 2025 18:52:49 -1000
Subject: [PATCH 72/90] [mdns] Use FixedVector for txt_records to reduce flash
 usage

---
 esphome/components/mdns/mdns_component.cpp | 4 ++--
 esphome/components/mdns/mdns_component.h   | 2 +-
 esphome/core/helpers.h                     | 9 +++++++++
 3 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/esphome/components/mdns/mdns_component.cpp b/esphome/components/mdns/mdns_component.cpp
index fea3ced99f..ef585db51b 100644
--- a/esphome/components/mdns/mdns_component.cpp
+++ b/esphome/components/mdns/mdns_component.cpp
@@ -83,7 +83,7 @@ void MDNSComponent::compile_records_(StaticVector<MDNSService, MDNS_SERVICE_COUN
 #endif
 
     auto &txt_records = service.txt_records;
-    txt_records.reserve(txt_count);
+    txt_records.init(txt_count);
 
     if (!friendly_name_empty) {
       txt_records.push_back({MDNS_STR(TXT_FRIENDLY_NAME), MDNS_STR(friendly_name.c_str())});
@@ -171,7 +171,7 @@ void MDNSComponent::compile_records_(StaticVector<MDNSService, MDNS_SERVICE_COUN
   fallback_service.service_type = MDNS_STR(SERVICE_HTTP);
   fallback_service.proto = MDNS_STR(SERVICE_TCP);
   fallback_service.port = USE_WEBSERVER_PORT;
-  fallback_service.txt_records.push_back({MDNS_STR(TXT_VERSION), MDNS_STR(VALUE_VERSION)});
+  fallback_service.txt_records = {{MDNS_STR(TXT_VERSION), MDNS_STR(VALUE_VERSION)}};
 #endif
 
 #ifdef USE_MDNS_STORE_SERVICES
diff --git a/esphome/components/mdns/mdns_component.h b/esphome/components/mdns/mdns_component.h
index 62476e9504..35371fd739 100644
--- a/esphome/components/mdns/mdns_component.h
+++ b/esphome/components/mdns/mdns_component.h
@@ -38,7 +38,7 @@ struct MDNSService {
   // as defined in RFC6763 Section 7, like "_tcp" or "_udp"
   const MDNSString *proto;
   TemplatableValue<uint16_t> port;
-  std::vector<MDNSTXTRecord> txt_records;
+  FixedVector<MDNSTXTRecord> txt_records;
 };
 
 class MDNSComponent : public Component {
diff --git a/esphome/core/helpers.h b/esphome/core/helpers.h
index e352c9c415..b94826629f 100644
--- a/esphome/core/helpers.h
+++ b/esphome/core/helpers.h
@@ -197,6 +197,15 @@ template<typename T> class FixedVector {
  public:
   FixedVector() = default;
 
+  /// Constructor from initializer list - allocates exact size needed
+  /// This enables brace initialization: FixedVector<int> v = {1, 2, 3};
+  FixedVector(std::initializer_list<T> init) {
+    init(init.size());
+    for (const auto &item : init) {
+      push_back(item);
+    }
+  }
+
   ~FixedVector() { cleanup_(); }
 
   // Disable copy operations (avoid accidental expensive copies)

From ac35c97a44a339dd6e69bcc503a5aa9edec5e156 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Mon, 13 Oct 2025 18:59:46 -1000
Subject: [PATCH 73/90] we need copy now

---
 esphome/core/helpers.h | 27 ++++++++++++++++++++++++---
 1 file changed, 24 insertions(+), 3 deletions(-)

diff --git a/esphome/core/helpers.h b/esphome/core/helpers.h
index b94826629f..c0e73b70e0 100644
--- a/esphome/core/helpers.h
+++ b/esphome/core/helpers.h
@@ -208,9 +208,30 @@ template<typename T> class FixedVector {
 
   ~FixedVector() { cleanup_(); }
 
-  // Disable copy operations (avoid accidental expensive copies)
-  FixedVector(const FixedVector &) = delete;
-  FixedVector &operator=(const FixedVector &) = delete;
+  // Copy constructor - performs deep copy
+  FixedVector(const FixedVector &other) {
+    if (other.size_ > 0) {
+      init(other.size_);
+      for (size_t i = 0; i < other.size_; i++) {
+        push_back(other.data_[i]);
+      }
+    }
+  }
+
+  // Copy assignment operator - performs deep copy
+  FixedVector &operator=(const FixedVector &other) {
+    if (this != &other) {
+      cleanup_();
+      reset_();
+      if (other.size_ > 0) {
+        init(other.size_);
+        for (size_t i = 0; i < other.size_; i++) {
+          push_back(other.data_[i]);
+        }
+      }
+    }
+    return *this;
+  }
 
   // Enable move semantics (allows use in move-only containers like std::vector)
   FixedVector(FixedVector &&other) noexcept : data_(other.data_), size_(other.size_), capacity_(other.capacity_) {

From 45014db02796aad16e103f649f30f955baa6c242 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Mon, 13 Oct 2025 19:05:26 -1000
Subject: [PATCH 74/90] preen

---
 esphome/components/mdns/mdns_component.cpp |  4 +--
 esphome/core/helpers.h                     | 29 +++-------------------
 2 files changed, 6 insertions(+), 27 deletions(-)

diff --git a/esphome/components/mdns/mdns_component.cpp b/esphome/components/mdns/mdns_component.cpp
index ef585db51b..7b36fce229 100644
--- a/esphome/components/mdns/mdns_component.cpp
+++ b/esphome/components/mdns/mdns_component.cpp
@@ -175,8 +175,8 @@ void MDNSComponent::compile_records_(StaticVector<MDNSService, MDNS_SERVICE_COUN
 #endif
 
 #ifdef USE_MDNS_STORE_SERVICES
-  // Copy to member variable if storage is enabled (verbose logging, OpenThread, or extra services)
-  this->services_ = services;
+  // Move to member variable if storage is enabled (verbose logging, OpenThread, or extra services)
+  this->services_ = std::move(services);
 #endif
 }
 
diff --git a/esphome/core/helpers.h b/esphome/core/helpers.h
index c0e73b70e0..a9c0427917 100644
--- a/esphome/core/helpers.h
+++ b/esphome/core/helpers.h
@@ -208,32 +208,11 @@ template<typename T> class FixedVector {
 
   ~FixedVector() { cleanup_(); }
 
-  // Copy constructor - performs deep copy
-  FixedVector(const FixedVector &other) {
-    if (other.size_ > 0) {
-      init(other.size_);
-      for (size_t i = 0; i < other.size_; i++) {
-        push_back(other.data_[i]);
-      }
-    }
-  }
+  // Disable copy operations - use std::move() to transfer ownership
+  FixedVector(const FixedVector &) = delete;
+  FixedVector &operator=(const FixedVector &) = delete;
 
-  // Copy assignment operator - performs deep copy
-  FixedVector &operator=(const FixedVector &other) {
-    if (this != &other) {
-      cleanup_();
-      reset_();
-      if (other.size_ > 0) {
-        init(other.size_);
-        for (size_t i = 0; i < other.size_; i++) {
-          push_back(other.data_[i]);
-        }
-      }
-    }
-    return *this;
-  }
-
-  // Enable move semantics (allows use in move-only containers like std::vector)
+  // Enable move semantics
   FixedVector(FixedVector &&other) noexcept : data_(other.data_), size_(other.size_), capacity_(other.capacity_) {
     other.reset_();
   }

From fc30326e603834154703b66e8a373bc2cf1ad498 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Mon, 13 Oct 2025 19:06:02 -1000
Subject: [PATCH 75/90] preen

---
 esphome/core/helpers.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/esphome/core/helpers.h b/esphome/core/helpers.h
index a9c0427917..b94826629f 100644
--- a/esphome/core/helpers.h
+++ b/esphome/core/helpers.h
@@ -208,11 +208,11 @@ template<typename T> class FixedVector {
 
   ~FixedVector() { cleanup_(); }
 
-  // Disable copy operations - use std::move() to transfer ownership
+  // Disable copy operations (avoid accidental expensive copies)
   FixedVector(const FixedVector &) = delete;
   FixedVector &operator=(const FixedVector &) = delete;
 
-  // Enable move semantics
+  // Enable move semantics (allows use in move-only containers like std::vector)
   FixedVector(FixedVector &&other) noexcept : data_(other.data_), size_(other.size_), capacity_(other.capacity_) {
     other.reset_();
   }

From 24a7426a2a90f12f9a1a511422358b91fb2caba0 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Mon, 13 Oct 2025 19:15:39 -1000
Subject: [PATCH 76/90] rename to fix shadow

---
 esphome/core/helpers.h | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/esphome/core/helpers.h b/esphome/core/helpers.h
index b94826629f..75ca600292 100644
--- a/esphome/core/helpers.h
+++ b/esphome/core/helpers.h
@@ -199,9 +199,9 @@ template<typename T> class FixedVector {
 
   /// Constructor from initializer list - allocates exact size needed
   /// This enables brace initialization: FixedVector<int> v = {1, 2, 3};
-  FixedVector(std::initializer_list<T> init) {
-    init(init.size());
-    for (const auto &item : init) {
+  FixedVector(std::initializer_list<T> init_list) {
+    init(init_list.size());
+    for (const auto &item : init_list) {
       push_back(item);
     }
   }

From 7492d7a437bb3f747b6321282853903a43882ad5 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Mon, 13 Oct 2025 19:27:33 -1000
Subject: [PATCH 77/90] [api] Convert HomeassistantActionRequest vectors to
 FixedVector for flash savings

---
 esphome/components/api/api.proto              |  6 ++--
 esphome/components/api/api_pb2.h              |  6 ++--
 esphome/components/api/custom_api_device.h    |  8 ++---
 .../components/api/homeassistant_service.h    | 31 ++++++++-----------
 .../number/homeassistant_number.cpp           |  7 ++---
 .../switch/homeassistant_switch.cpp           |  4 +--
 6 files changed, 28 insertions(+), 34 deletions(-)

diff --git a/esphome/components/api/api.proto b/esphome/components/api/api.proto
index 9b714d00f1..34864c5ce8 100644
--- a/esphome/components/api/api.proto
+++ b/esphome/components/api/api.proto
@@ -776,9 +776,9 @@ message HomeassistantActionRequest {
   option (ifdef) = "USE_API_HOMEASSISTANT_SERVICES";
 
   string service = 1;
-  repeated HomeassistantServiceMap data = 2;
-  repeated HomeassistantServiceMap data_template = 3;
-  repeated HomeassistantServiceMap variables = 4;
+  repeated HomeassistantServiceMap data = 2 [(fixed_vector) = true];
+  repeated HomeassistantServiceMap data_template = 3 [(fixed_vector) = true];
+  repeated HomeassistantServiceMap variables = 4 [(fixed_vector) = true];
   bool is_event = 5;
   uint32 call_id = 6 [(field_ifdef) = "USE_API_HOMEASSISTANT_ACTION_RESPONSES"];
   bool wants_response = 7 [(field_ifdef) = "USE_API_HOMEASSISTANT_ACTION_RESPONSES_JSON"];
diff --git a/esphome/components/api/api_pb2.h b/esphome/components/api/api_pb2.h
index 1798458393..7d6b31ca3c 100644
--- a/esphome/components/api/api_pb2.h
+++ b/esphome/components/api/api_pb2.h
@@ -1110,9 +1110,9 @@ class HomeassistantActionRequest final : public ProtoMessage {
 #endif
   StringRef service_ref_{};
   void set_service(const StringRef &ref) { this->service_ref_ = ref; }
-  std::vector<HomeassistantServiceMap> data{};
-  std::vector<HomeassistantServiceMap> data_template{};
-  std::vector<HomeassistantServiceMap> variables{};
+  FixedVector<HomeassistantServiceMap> data{};
+  FixedVector<HomeassistantServiceMap> data_template{};
+  FixedVector<HomeassistantServiceMap> variables{};
   bool is_event{false};
 #ifdef USE_API_HOMEASSISTANT_ACTION_RESPONSES
   uint32_t call_id{0};
diff --git a/esphome/components/api/custom_api_device.h b/esphome/components/api/custom_api_device.h
index 0c6e49d6ca..711eba2444 100644
--- a/esphome/components/api/custom_api_device.h
+++ b/esphome/components/api/custom_api_device.h
@@ -201,9 +201,9 @@ class CustomAPIDevice {
   void call_homeassistant_service(const std::string &service_name, const std::map<std::string, std::string> &data) {
     HomeassistantActionRequest resp;
     resp.set_service(StringRef(service_name));
+    resp.data.init(data.size());
     for (auto &it : data) {
-      resp.data.emplace_back();
-      auto &kv = resp.data.back();
+      auto &kv = resp.data.emplace_back();
       kv.set_key(StringRef(it.first));
       kv.value = it.second;
     }
@@ -244,9 +244,9 @@ class CustomAPIDevice {
     HomeassistantActionRequest resp;
     resp.set_service(StringRef(service_name));
     resp.is_event = true;
+    resp.data.init(data.size());
     for (auto &it : data) {
-      resp.data.emplace_back();
-      auto &kv = resp.data.back();
+      auto &kv = resp.data.emplace_back();
       kv.set_key(StringRef(it.first));
       kv.value = it.second;
     }
diff --git a/esphome/components/api/homeassistant_service.h b/esphome/components/api/homeassistant_service.h
index 730024f7b7..b75bca6f71 100644
--- a/esphome/components/api/homeassistant_service.h
+++ b/esphome/components/api/homeassistant_service.h
@@ -122,29 +122,24 @@ template<typename... Ts> class HomeAssistantServiceCallAction : public Action<Ts
   Trigger<std::string, Ts...> *get_error_trigger() const { return this->error_trigger_; }
 #endif  // USE_API_HOMEASSISTANT_ACTION_RESPONSES
 
+  template<typename VectorType, typename SourceType>
+  static void populate_service_map_(VectorType &dest, SourceType &source, Ts... x) {
+    dest.init(source.size());
+    for (auto &it : source) {
+      auto &kv = dest.emplace_back();
+      kv.set_key(StringRef(it.key));
+      kv.value = it.value.value(x...);
+    }
+  }
+
   void play(Ts... x) override {
     HomeassistantActionRequest resp;
     std::string service_value = this->service_.value(x...);
     resp.set_service(StringRef(service_value));
     resp.is_event = this->flags_.is_event;
-    for (auto &it : this->data_) {
-      resp.data.emplace_back();
-      auto &kv = resp.data.back();
-      kv.set_key(StringRef(it.key));
-      kv.value = it.value.value(x...);
-    }
-    for (auto &it : this->data_template_) {
-      resp.data_template.emplace_back();
-      auto &kv = resp.data_template.back();
-      kv.set_key(StringRef(it.key));
-      kv.value = it.value.value(x...);
-    }
-    for (auto &it : this->variables_) {
-      resp.variables.emplace_back();
-      auto &kv = resp.variables.back();
-      kv.set_key(StringRef(it.key));
-      kv.value = it.value.value(x...);
-    }
+    populate_service_map_(resp.data, this->data_, x...);
+    populate_service_map_(resp.data_template, this->data_template_, x...);
+    populate_service_map_(resp.variables, this->variables_, x...);
 
 #ifdef USE_API_HOMEASSISTANT_ACTION_RESPONSES
     if (this->flags_.wants_status) {
diff --git a/esphome/components/homeassistant/number/homeassistant_number.cpp b/esphome/components/homeassistant/number/homeassistant_number.cpp
index c9fb006568..9963f3431d 100644
--- a/esphome/components/homeassistant/number/homeassistant_number.cpp
+++ b/esphome/components/homeassistant/number/homeassistant_number.cpp
@@ -90,13 +90,12 @@ void HomeassistantNumber::control(float value) {
   api::HomeassistantActionRequest resp;
   resp.set_service(SERVICE_NAME);
 
-  resp.data.emplace_back();
-  auto &entity_id = resp.data.back();
+  resp.data.init(2);
+  auto &entity_id = resp.data.emplace_back();
   entity_id.set_key(ENTITY_ID_KEY);
   entity_id.value = this->entity_id_;
 
-  resp.data.emplace_back();
-  auto &entity_value = resp.data.back();
+  auto &entity_value = resp.data.emplace_back();
   entity_value.set_key(VALUE_KEY);
   entity_value.value = to_string(value);
 
diff --git a/esphome/components/homeassistant/switch/homeassistant_switch.cpp b/esphome/components/homeassistant/switch/homeassistant_switch.cpp
index 8feec26fe6..27d3705fc2 100644
--- a/esphome/components/homeassistant/switch/homeassistant_switch.cpp
+++ b/esphome/components/homeassistant/switch/homeassistant_switch.cpp
@@ -51,8 +51,8 @@ void HomeassistantSwitch::write_state(bool state) {
     resp.set_service(SERVICE_OFF);
   }
 
-  resp.data.emplace_back();
-  auto &entity_id_kv = resp.data.back();
+  resp.data.init(1);
+  auto &entity_id_kv = resp.data.emplace_back();
   entity_id_kv.set_key(ENTITY_ID_KEY);
   entity_id_kv.value = this->entity_id_;
 

From 43d8386c4abbdec49409b68a17da67de98a1f507 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Mon, 13 Oct 2025 19:31:13 -1000
Subject: [PATCH 78/90] tidy

---
 esphome/components/api/homeassistant_service.h | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/esphome/components/api/homeassistant_service.h b/esphome/components/api/homeassistant_service.h
index b75bca6f71..b24a6470fe 100644
--- a/esphome/components/api/homeassistant_service.h
+++ b/esphome/components/api/homeassistant_service.h
@@ -123,7 +123,7 @@ template<typename... Ts> class HomeAssistantServiceCallAction : public Action<Ts
 #endif  // USE_API_HOMEASSISTANT_ACTION_RESPONSES
 
   template<typename VectorType, typename SourceType>
-  static void populate_service_map_(VectorType &dest, SourceType &source, Ts... x) {
+  static void populate_service_map(VectorType &dest, SourceType &source, Ts... x) {
     dest.init(source.size());
     for (auto &it : source) {
       auto &kv = dest.emplace_back();
@@ -137,9 +137,9 @@ template<typename... Ts> class HomeAssistantServiceCallAction : public Action<Ts
     std::string service_value = this->service_.value(x...);
     resp.set_service(StringRef(service_value));
     resp.is_event = this->flags_.is_event;
-    populate_service_map_(resp.data, this->data_, x...);
-    populate_service_map_(resp.data_template, this->data_template_, x...);
-    populate_service_map_(resp.variables, this->variables_, x...);
+    populate_service_map(resp.data, this->data_, x...);
+    populate_service_map(resp.data_template, this->data_template_, x...);
+    populate_service_map(resp.variables, this->variables_, x...);
 
 #ifdef USE_API_HOMEASSISTANT_ACTION_RESPONSES
     if (this->flags_.wants_status) {

From 05efb6e9255c98e37542434e62bd6d019bab5113 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Mon, 13 Oct 2025 21:14:32 -1000
Subject: [PATCH 79/90] refactor to avoid move

---
 esphome/components/mdns/mdns_component.cpp | 5 -----
 esphome/components/mdns/mdns_esp32.cpp     | 5 +++++
 esphome/components/mdns/mdns_esp8266.cpp   | 5 +++++
 esphome/components/mdns/mdns_libretiny.cpp | 5 +++++
 esphome/components/mdns/mdns_rp2040.cpp    | 5 +++++
 5 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/esphome/components/mdns/mdns_component.cpp b/esphome/components/mdns/mdns_component.cpp
index 7b36fce229..d476136554 100644
--- a/esphome/components/mdns/mdns_component.cpp
+++ b/esphome/components/mdns/mdns_component.cpp
@@ -173,11 +173,6 @@ void MDNSComponent::compile_records_(StaticVector<MDNSService, MDNS_SERVICE_COUN
   fallback_service.port = USE_WEBSERVER_PORT;
   fallback_service.txt_records = {{MDNS_STR(TXT_VERSION), MDNS_STR(VALUE_VERSION)}};
 #endif
-
-#ifdef USE_MDNS_STORE_SERVICES
-  // Move to member variable if storage is enabled (verbose logging, OpenThread, or extra services)
-  this->services_ = std::move(services);
-#endif
 }
 
 void MDNSComponent::dump_config() {
diff --git a/esphome/components/mdns/mdns_esp32.cpp b/esphome/components/mdns/mdns_esp32.cpp
index da47be7dbc..f2cb2d3ef5 100644
--- a/esphome/components/mdns/mdns_esp32.cpp
+++ b/esphome/components/mdns/mdns_esp32.cpp
@@ -12,8 +12,13 @@ namespace mdns {
 static const char *const TAG = "mdns";
 
 void MDNSComponent::setup() {
+#ifdef USE_MDNS_STORE_SERVICES
+  this->compile_records_(this->services_);
+  const auto &services = this->services_;
+#else
   StaticVector<MDNSService, MDNS_SERVICE_COUNT> services;
   this->compile_records_(services);
+#endif
 
   esp_err_t err = mdns_init();
   if (err != ESP_OK) {
diff --git a/esphome/components/mdns/mdns_esp8266.cpp b/esphome/components/mdns/mdns_esp8266.cpp
index 06503742db..25a3defa7b 100644
--- a/esphome/components/mdns/mdns_esp8266.cpp
+++ b/esphome/components/mdns/mdns_esp8266.cpp
@@ -12,8 +12,13 @@ namespace esphome {
 namespace mdns {
 
 void MDNSComponent::setup() {
+#ifdef USE_MDNS_STORE_SERVICES
+  this->compile_records_(this->services_);
+  const auto &services = this->services_;
+#else
   StaticVector<MDNSService, MDNS_SERVICE_COUNT> services;
   this->compile_records_(services);
+#endif
 
   MDNS.begin(this->hostname_.c_str());
 
diff --git a/esphome/components/mdns/mdns_libretiny.cpp b/esphome/components/mdns/mdns_libretiny.cpp
index a959482ff6..a3e317a2bf 100644
--- a/esphome/components/mdns/mdns_libretiny.cpp
+++ b/esphome/components/mdns/mdns_libretiny.cpp
@@ -12,8 +12,13 @@ namespace esphome {
 namespace mdns {
 
 void MDNSComponent::setup() {
+#ifdef USE_MDNS_STORE_SERVICES
+  this->compile_records_(this->services_);
+  const auto &services = this->services_;
+#else
   StaticVector<MDNSService, MDNS_SERVICE_COUNT> services;
   this->compile_records_(services);
+#endif
 
   MDNS.begin(this->hostname_.c_str());
 
diff --git a/esphome/components/mdns/mdns_rp2040.cpp b/esphome/components/mdns/mdns_rp2040.cpp
index 9dfb05bda9..791fa3934d 100644
--- a/esphome/components/mdns/mdns_rp2040.cpp
+++ b/esphome/components/mdns/mdns_rp2040.cpp
@@ -12,8 +12,13 @@ namespace esphome {
 namespace mdns {
 
 void MDNSComponent::setup() {
+#ifdef USE_MDNS_STORE_SERVICES
+  this->compile_records_(this->services_);
+  const auto &services = this->services_;
+#else
   StaticVector<MDNSService, MDNS_SERVICE_COUNT> services;
   this->compile_records_(services);
+#endif
 
   MDNS.begin(this->hostname_.c_str());
 

From 92a6aade174f6433ca3a1c09fd794ae1e2546b51 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Mon, 13 Oct 2025 21:35:26 -1000
Subject: [PATCH 80/90] fixes

---
 .ai/instructions.md | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/.ai/instructions.md b/.ai/instructions.md
index c608c9fd7e..5f314a0dc9 100644
--- a/.ai/instructions.md
+++ b/.ai/instructions.md
@@ -252,16 +252,18 @@ This document provides essential context for AI models interacting with this pro
            std::array<uint8_t, 256> buffer;
            ```
 
-        2. **Compile-time-known sizes with dynamic storage:** Use `StaticVector` from `esphome/core/helpers.h` when the maximum size is known at compile time but you need heap allocation.
+        2. **Compile-time-known fixed sizes with vector-like API:** Use `StaticVector` from `esphome/core/helpers.h` for fixed-size stack allocation with `push_back()` interface.
            ```cpp
            // Bad - generates STL realloc code (_M_realloc_insert)
            std::vector<ServiceRecord> services;
            services.reserve(5);  // Still includes reallocation machinery
 
-           // Good - compile-time max size, heap allocated, no reallocation machinery
-           StaticVector<ServiceRecord, MAX_SERVICES> services;  // Max size known at compile time
+           // Good - compile-time fixed size, stack allocated, no reallocation machinery
+           StaticVector<ServiceRecord, MAX_SERVICES> services;  // Allocates all MAX_SERVICES on stack
+           services.push_back(record1);  // Tracks count but all slots allocated
            ```
-           Use `cg.add_define("MAX_SERVICES", count)` to set the maximum from Python configuration.
+           Use `cg.add_define("MAX_SERVICES", count)` to set the size from Python configuration.
+           Like `std::array` but with vector-like API (`push_back()`, `size()`) and no STL reallocation code.
 
         3. **Runtime-known sizes:** Use `FixedVector` from `esphome/core/helpers.h` when the size is only known at runtime initialization.
            ```cpp

From e241e430647ba589bbd31917b9148424d5f6d327 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Mon, 13 Oct 2025 21:41:49 -1000
Subject: [PATCH 81/90] preen

---
 .../components/api/homeassistant_service.h    | 26 +++++++++----------
 1 file changed, 13 insertions(+), 13 deletions(-)

diff --git a/esphome/components/api/homeassistant_service.h b/esphome/components/api/homeassistant_service.h
index b24a6470fe..bd668d3cf8 100644
--- a/esphome/components/api/homeassistant_service.h
+++ b/esphome/components/api/homeassistant_service.h
@@ -122,24 +122,14 @@ template<typename... Ts> class HomeAssistantServiceCallAction : public Action<Ts
   Trigger<std::string, Ts...> *get_error_trigger() const { return this->error_trigger_; }
 #endif  // USE_API_HOMEASSISTANT_ACTION_RESPONSES
 
-  template<typename VectorType, typename SourceType>
-  static void populate_service_map(VectorType &dest, SourceType &source, Ts... x) {
-    dest.init(source.size());
-    for (auto &it : source) {
-      auto &kv = dest.emplace_back();
-      kv.set_key(StringRef(it.key));
-      kv.value = it.value.value(x...);
-    }
-  }
-
   void play(Ts... x) override {
     HomeassistantActionRequest resp;
     std::string service_value = this->service_.value(x...);
     resp.set_service(StringRef(service_value));
     resp.is_event = this->flags_.is_event;
-    populate_service_map(resp.data, this->data_, x...);
-    populate_service_map(resp.data_template, this->data_template_, x...);
-    populate_service_map(resp.variables, this->variables_, x...);
+    this->populate_service_map_(resp.data, this->data_, x...);
+    this->populate_service_map_(resp.data_template, this->data_template_, x...);
+    this->populate_service_map_(resp.variables, this->variables_, x...);
 
 #ifdef USE_API_HOMEASSISTANT_ACTION_RESPONSES
     if (this->flags_.wants_status) {
@@ -184,6 +174,16 @@ template<typename... Ts> class HomeAssistantServiceCallAction : public Action<Ts
   }
 
  protected:
+  template<typename VectorType, typename SourceType>
+  static void populate_service_map(VectorType &dest, SourceType &source, Ts... x) {
+    dest.init(source.size());
+    for (auto &it : source) {
+      auto &kv = dest.emplace_back();
+      kv.set_key(StringRef(it.key));
+      kv.value = it.value.value(x...);
+    }
+  }
+
   APIServer *parent_;
   TemplatableStringValue<Ts...> service_{};
   std::vector<TemplatableKeyValuePair<Ts...>> data_;

From 0fca842afe9212189b8503908475fb26ab9dd756 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Mon, 13 Oct 2025 21:41:57 -1000
Subject: [PATCH 82/90] preen

---
 esphome/components/api/homeassistant_service.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/esphome/components/api/homeassistant_service.h b/esphome/components/api/homeassistant_service.h
index bd668d3cf8..9c2844fbed 100644
--- a/esphome/components/api/homeassistant_service.h
+++ b/esphome/components/api/homeassistant_service.h
@@ -175,7 +175,7 @@ template<typename... Ts> class HomeAssistantServiceCallAction : public Action<Ts
 
  protected:
   template<typename VectorType, typename SourceType>
-  static void populate_service_map(VectorType &dest, SourceType &source, Ts... x) {
+  static void populate_service_map_(VectorType &dest, SourceType &source, Ts... x) {
     dest.init(source.size());
     for (auto &it : source) {
       auto &kv = dest.emplace_back();

From 5ebb68b719088f34447a8bf29f030d87cefe8193 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Mon, 13 Oct 2025 21:45:52 -1000
Subject: [PATCH 83/90] fixed

---
 esphome/components/api/homeassistant_service.h | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/esphome/components/api/homeassistant_service.h b/esphome/components/api/homeassistant_service.h
index 9c2844fbed..46e89cb39f 100644
--- a/esphome/components/api/homeassistant_service.h
+++ b/esphome/components/api/homeassistant_service.h
@@ -127,9 +127,9 @@ template<typename... Ts> class HomeAssistantServiceCallAction : public Action<Ts
     std::string service_value = this->service_.value(x...);
     resp.set_service(StringRef(service_value));
     resp.is_event = this->flags_.is_event;
-    this->populate_service_map_(resp.data, this->data_, x...);
-    this->populate_service_map_(resp.data_template, this->data_template_, x...);
-    this->populate_service_map_(resp.variables, this->variables_, x...);
+    this->populate_service_map(resp.data, this->data_, x...);
+    this->populate_service_map(resp.data_template, this->data_template_, x...);
+    this->populate_service_map(resp.variables, this->variables_, x...);
 
 #ifdef USE_API_HOMEASSISTANT_ACTION_RESPONSES
     if (this->flags_.wants_status) {
@@ -175,7 +175,7 @@ template<typename... Ts> class HomeAssistantServiceCallAction : public Action<Ts
 
  protected:
   template<typename VectorType, typename SourceType>
-  static void populate_service_map_(VectorType &dest, SourceType &source, Ts... x) {
+  static void populate_service_map(VectorType &dest, SourceType &source, Ts... x) {
     dest.init(source.size());
     for (auto &it : source) {
       auto &kv = dest.emplace_back();

From ce3bd55a389917f908cf56abd4b028f7e16722f9 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Mon, 13 Oct 2025 21:52:24 -1000
Subject: [PATCH 84/90] [api] Use FixedVector for ListEntitiesServicesResponse
 args

---
 esphome/components/api/api.proto       | 2 +-
 esphome/components/api/api_pb2.h       | 2 +-
 esphome/components/api/user_services.h | 4 ++--
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/esphome/components/api/api.proto b/esphome/components/api/api.proto
index 9b714d00f1..f7b65c34e3 100644
--- a/esphome/components/api/api.proto
+++ b/esphome/components/api/api.proto
@@ -866,7 +866,7 @@ message ListEntitiesServicesResponse {
 
   string name = 1;
   fixed32 key = 2;
-  repeated ListEntitiesServicesArgument args = 3;
+  repeated ListEntitiesServicesArgument args = 3 [(fixed_vector) = true];
 }
 message ExecuteServiceArgument {
   option (ifdef) = "USE_API_SERVICES";
diff --git a/esphome/components/api/api_pb2.h b/esphome/components/api/api_pb2.h
index 1798458393..64419eaaa8 100644
--- a/esphome/components/api/api_pb2.h
+++ b/esphome/components/api/api_pb2.h
@@ -1263,7 +1263,7 @@ class ListEntitiesServicesResponse final : public ProtoMessage {
   StringRef name_ref_{};
   void set_name(const StringRef &ref) { this->name_ref_ = ref; }
   uint32_t key{0};
-  std::vector<ListEntitiesServicesArgument> args{};
+  FixedVector<ListEntitiesServicesArgument> args{};
   void encode(ProtoWriteBuffer buffer) const override;
   void calculate_size(ProtoSize &size) const override;
 #ifdef HAS_PROTO_MESSAGE_DUMP
diff --git a/esphome/components/api/user_services.h b/esphome/components/api/user_services.h
index 3996c921a9..29843a2f78 100644
--- a/esphome/components/api/user_services.h
+++ b/esphome/components/api/user_services.h
@@ -35,9 +35,9 @@ template<typename... Ts> class UserServiceBase : public UserServiceDescriptor {
     msg.set_name(StringRef(this->name_));
     msg.key = this->key_;
     std::array<enums::ServiceArgType, sizeof...(Ts)> arg_types = {to_service_arg_type<Ts>()...};
+    msg.args.init(sizeof...(Ts));
     for (size_t i = 0; i < sizeof...(Ts); i++) {
-      msg.args.emplace_back();
-      auto &arg = msg.args.back();
+      auto &arg = msg.args.emplace_back();
       arg.type = arg_types[i];
       arg.set_name(StringRef(this->arg_names_[i]));
     }

From 1acd7d4672267a14297eada2aa55192eb3817f28 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Mon, 13 Oct 2025 21:56:11 -1000
Subject: [PATCH 85/90] Update esphome/core/helpers.h

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
---
 esphome/core/helpers.h | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/esphome/core/helpers.h b/esphome/core/helpers.h
index 75ca600292..326718e974 100644
--- a/esphome/core/helpers.h
+++ b/esphome/core/helpers.h
@@ -201,9 +201,12 @@ template<typename T> class FixedVector {
   /// This enables brace initialization: FixedVector<int> v = {1, 2, 3};
   FixedVector(std::initializer_list<T> init_list) {
     init(init_list.size());
+    size_t idx = 0;
     for (const auto &item : init_list) {
-      push_back(item);
+      new (data_ + idx) T(item);
+      ++idx;
     }
+    size_ = init_list.size();
   }
 
   ~FixedVector() { cleanup_(); }

From 87ae07e7be5d592298b38abcacdfb8bac20df208 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Mon, 13 Oct 2025 22:27:41 -1000
Subject: [PATCH 86/90] [light] Use FixedVector for LightState effects list

---
 esphome/components/light/light_state.cpp | 5 +++--
 esphome/components/light/light_state.h   | 6 +++---
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/esphome/components/light/light_state.cpp b/esphome/components/light/light_state.cpp
index f18d5ba1de..1d139e49e7 100644
--- a/esphome/components/light/light_state.cpp
+++ b/esphome/components/light/light_state.cpp
@@ -177,9 +177,10 @@ void LightState::set_gamma_correct(float gamma_correct) { this->gamma_correct_ =
 void LightState::set_restore_mode(LightRestoreMode restore_mode) { this->restore_mode_ = restore_mode; }
 void LightState::set_initial_state(const LightStateRTCState &initial_state) { this->initial_state_ = initial_state; }
 bool LightState::supports_effects() { return !this->effects_.empty(); }
-const std::vector<LightEffect *> &LightState::get_effects() const { return this->effects_; }
+const FixedVector<LightEffect *> &LightState::get_effects() const { return this->effects_; }
 void LightState::add_effects(const std::vector<LightEffect *> &effects) {
-  this->effects_.reserve(this->effects_.size() + effects.size());
+  // Called once from Python codegen during setup with all effects from YAML config
+  this->effects_.init(effects.size());
   for (auto *effect : effects) {
     this->effects_.push_back(effect);
   }
diff --git a/esphome/components/light/light_state.h b/esphome/components/light/light_state.h
index 1427c02c35..87a509cba6 100644
--- a/esphome/components/light/light_state.h
+++ b/esphome/components/light/light_state.h
@@ -11,7 +11,7 @@
 #include "light_traits.h"
 #include "light_transformer.h"
 
-#include <vector>
+#include "esphome/core/helpers.h"
 #include <strings.h>
 
 namespace esphome {
@@ -159,7 +159,7 @@ class LightState : public EntityBase, public Component {
   bool supports_effects();
 
   /// Get all effects for this light state.
-  const std::vector<LightEffect *> &get_effects() const;
+  const FixedVector<LightEffect *> &get_effects() const;
 
   /// Add effects for this light state.
   void add_effects(const std::vector<LightEffect *> &effects);
@@ -260,7 +260,7 @@ class LightState : public EntityBase, public Component {
   /// The currently active transformer for this light (transition/flash).
   std::unique_ptr<LightTransformer> transformer_{nullptr};
   /// List of effects for this light.
-  std::vector<LightEffect *> effects_;
+  FixedVector<LightEffect *> effects_;
   /// Object used to store the persisted values of the light.
   ESPPreferenceObject rtc_;
   /// Value for storing the index of the currently active effect. 0 if no effect is active

From 3cf24a259cbb85fe314d793896ebecd713639fd0 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Mon, 13 Oct 2025 22:46:45 -1000
Subject: [PATCH 87/90] [web_server_idf] Use std::vector instead of std::set
 for SSE sessions

---
 .../components/web_server_idf/web_server_idf.cpp    | 13 +++++++------
 esphome/components/web_server_idf/web_server_idf.h  |  6 ++++--
 2 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/esphome/components/web_server_idf/web_server_idf.cpp b/esphome/components/web_server_idf/web_server_idf.cpp
index d90efd18bc..c3ba7ddc2b 100644
--- a/esphome/components/web_server_idf/web_server_idf.cpp
+++ b/esphome/components/web_server_idf/web_server_idf.cpp
@@ -380,24 +380,25 @@ void AsyncEventSource::handleRequest(AsyncWebServerRequest *request) {
   if (this->on_connect_) {
     this->on_connect_(rsp);
   }
-  this->sessions_.insert(rsp);
+  this->sessions_.push_back(rsp);
 }
 
 void AsyncEventSource::loop() {
   // Clean up dead sessions safely
   // This follows the ESP-IDF pattern where free_ctx marks resources as dead
   // and the main loop handles the actual cleanup to avoid race conditions
-  auto it = this->sessions_.begin();
-  while (it != this->sessions_.end()) {
-    auto *ses = *it;
+  for (size_t i = 0; i < this->sessions_.size();) {
+    auto *ses = this->sessions_[i];
     // If the session has a dead socket (marked by destroy callback)
     if (ses->fd_.load() == 0) {
       ESP_LOGD(TAG, "Removing dead event source session");
-      it = this->sessions_.erase(it);
       delete ses;  // NOLINT(cppcoreguidelines-owning-memory)
+      // Remove by swapping with last element (O(1) removal, order doesn't matter for sessions)
+      this->sessions_[i] = this->sessions_.back();
+      this->sessions_.pop_back();
     } else {
       ses->loop();
-      ++it;
+      ++i;
     }
   }
 }
diff --git a/esphome/components/web_server_idf/web_server_idf.h b/esphome/components/web_server_idf/web_server_idf.h
index bf93dcbd34..5ec6fec009 100644
--- a/esphome/components/web_server_idf/web_server_idf.h
+++ b/esphome/components/web_server_idf/web_server_idf.h
@@ -8,7 +8,6 @@
 #include <functional>
 #include <list>
 #include <map>
-#include <set>
 #include <string>
 #include <utility>
 #include <vector>
@@ -315,7 +314,10 @@ class AsyncEventSource : public AsyncWebHandler {
 
  protected:
   std::string url_;
-  std::set<AsyncEventSourceResponse *> sessions_;
+  // Use vector instead of set: SSE sessions are typically 1-5 connections (browsers, dashboards).
+  // Linear search is faster than red-black tree overhead for this small dataset.
+  // Only operations needed: add session, remove session, iterate sessions - no need for sorted order.
+  std::vector<AsyncEventSourceResponse *> sessions_;
   connect_handler_t on_connect_{};
   esphome::web_server::WebServer *web_server_;
 };

From 793e75a09398082ace5c07675532fa65b303ee71 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Tue, 14 Oct 2025 09:28:56 -1000
Subject: [PATCH 88/90] [core] Use FixedVector for automation condition vectors
 to save 384 bytes flash

---
 esphome/core/base_automation.h | 13 +++++++------
 esphome/core/helpers.h         | 12 ++++++++++++
 2 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/esphome/core/base_automation.h b/esphome/core/base_automation.h
index ba942e5e43..f1248e0035 100644
--- a/esphome/core/base_automation.h
+++ b/esphome/core/base_automation.h
@@ -7,6 +7,7 @@
 #include "esphome/core/preferences.h"
 #include "esphome/core/scheduler.h"
 #include "esphome/core/application.h"
+#include "esphome/core/helpers.h"
 
 #include <vector>
 
@@ -14,7 +15,7 @@ namespace esphome {
 
 template<typename... Ts> class AndCondition : public Condition<Ts...> {
  public:
-  explicit AndCondition(const std::vector<Condition<Ts...> *> &conditions) : conditions_(conditions) {}
+  explicit AndCondition(std::initializer_list<Condition<Ts...> *> conditions) : conditions_(conditions) {}
   bool check(Ts... x) override {
     for (auto *condition : this->conditions_) {
       if (!condition->check(x...))
@@ -25,12 +26,12 @@ template<typename... Ts> class AndCondition : public Condition<Ts...> {
   }
 
  protected:
-  std::vector<Condition<Ts...> *> conditions_;
+  FixedVector<Condition<Ts...> *> conditions_;
 };
 
 template<typename... Ts> class OrCondition : public Condition<Ts...> {
  public:
-  explicit OrCondition(const std::vector<Condition<Ts...> *> &conditions) : conditions_(conditions) {}
+  explicit OrCondition(std::initializer_list<Condition<Ts...> *> conditions) : conditions_(conditions) {}
   bool check(Ts... x) override {
     for (auto *condition : this->conditions_) {
       if (condition->check(x...))
@@ -41,7 +42,7 @@ template<typename... Ts> class OrCondition : public Condition<Ts...> {
   }
 
  protected:
-  std::vector<Condition<Ts...> *> conditions_;
+  FixedVector<Condition<Ts...> *> conditions_;
 };
 
 template<typename... Ts> class NotCondition : public Condition<Ts...> {
@@ -55,7 +56,7 @@ template<typename... Ts> class NotCondition : public Condition<Ts...> {
 
 template<typename... Ts> class XorCondition : public Condition<Ts...> {
  public:
-  explicit XorCondition(const std::vector<Condition<Ts...> *> &conditions) : conditions_(conditions) {}
+  explicit XorCondition(std::initializer_list<Condition<Ts...> *> conditions) : conditions_(conditions) {}
   bool check(Ts... x) override {
     size_t result = 0;
     for (auto *condition : this->conditions_) {
@@ -66,7 +67,7 @@ template<typename... Ts> class XorCondition : public Condition<Ts...> {
   }
 
  protected:
-  std::vector<Condition<Ts...> *> conditions_;
+  FixedVector<Condition<Ts...> *> conditions_;
 };
 
 template<typename... Ts> class LambdaCondition : public Condition<Ts...> {
diff --git a/esphome/core/helpers.h b/esphome/core/helpers.h
index e352c9c415..326718e974 100644
--- a/esphome/core/helpers.h
+++ b/esphome/core/helpers.h
@@ -197,6 +197,18 @@ template<typename T> class FixedVector {
  public:
   FixedVector() = default;
 
+  /// Constructor from initializer list - allocates exact size needed
+  /// This enables brace initialization: FixedVector<int> v = {1, 2, 3};
+  FixedVector(std::initializer_list<T> init_list) {
+    init(init_list.size());
+    size_t idx = 0;
+    for (const auto &item : init_list) {
+      new (data_ + idx) T(item);
+      ++idx;
+    }
+    size_ = init_list.size();
+  }
+
   ~FixedVector() { cleanup_(); }
 
   // Disable copy operations (avoid accidental expensive copies)

From 837a0bf6df011224be5649d991d1fb8277c2b035 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Tue, 14 Oct 2025 12:18:12 -1000
Subject: [PATCH 89/90] [pzemac, pzemdc, sdm_meter] Fix pin conflicts in
 ESP32-IDF tests

---
 tests/components/pzemac/test.esp32-idf.yaml    | 1 +
 tests/components/pzemdc/test.esp32-idf.yaml    | 1 +
 tests/components/sdm_meter/test.esp32-idf.yaml | 1 +
 3 files changed, 3 insertions(+)

diff --git a/tests/components/pzemac/test.esp32-idf.yaml b/tests/components/pzemac/test.esp32-idf.yaml
index 37d98696cc..b631e16677 100644
--- a/tests/components/pzemac/test.esp32-idf.yaml
+++ b/tests/components/pzemac/test.esp32-idf.yaml
@@ -1,6 +1,7 @@
 substitutions:
   tx_pin: GPIO4
   rx_pin: GPIO5
+  flow_control_pin: GPIO13
 
 packages:
   modbus: !include ../../test_build_components/common/modbus/esp32-idf.yaml
diff --git a/tests/components/pzemdc/test.esp32-idf.yaml b/tests/components/pzemdc/test.esp32-idf.yaml
index 37d98696cc..b631e16677 100644
--- a/tests/components/pzemdc/test.esp32-idf.yaml
+++ b/tests/components/pzemdc/test.esp32-idf.yaml
@@ -1,6 +1,7 @@
 substitutions:
   tx_pin: GPIO4
   rx_pin: GPIO5
+  flow_control_pin: GPIO13
 
 packages:
   modbus: !include ../../test_build_components/common/modbus/esp32-idf.yaml
diff --git a/tests/components/sdm_meter/test.esp32-idf.yaml b/tests/components/sdm_meter/test.esp32-idf.yaml
index 37d98696cc..b631e16677 100644
--- a/tests/components/sdm_meter/test.esp32-idf.yaml
+++ b/tests/components/sdm_meter/test.esp32-idf.yaml
@@ -1,6 +1,7 @@
 substitutions:
   tx_pin: GPIO4
   rx_pin: GPIO5
+  flow_control_pin: GPIO13
 
 packages:
   modbus: !include ../../test_build_components/common/modbus/esp32-idf.yaml

From b927cea0d61795ad112c7819a9fa7d35fe704b89 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Tue, 14 Oct 2025 16:23:06 -1000
Subject: [PATCH 90/90] [git] Automatically recover from broken git
 repositories in external_components

---
 esphome/git.py               |  59 +++++++++----
 tests/unit_tests/test_git.py | 160 +++++++++++++++++++++++++++++++++++
 2 files changed, 204 insertions(+), 15 deletions(-)

diff --git a/esphome/git.py b/esphome/git.py
index 62fe37a3fe..7f023e7834 100644
--- a/esphome/git.py
+++ b/esphome/git.py
@@ -5,6 +5,7 @@ import hashlib
 import logging
 from pathlib import Path
 import re
+import shutil
 import subprocess
 import urllib.parse
 
@@ -55,6 +56,7 @@ def clone_or_update(
     username: str = None,
     password: str = None,
     submodules: list[str] | None = None,
+    _recover_broken: bool = True,
 ) -> tuple[Path, Callable[[], None] | None]:
     key = f"{url}@{ref}"
 
@@ -80,7 +82,7 @@ def clone_or_update(
 
         if submodules is not None:
             _LOGGER.info(
-                "Initialising submodules (%s) for %s", ", ".join(submodules), key
+                "Initializing submodules (%s) for %s", ", ".join(submodules), key
             )
             run_git_command(
                 ["git", "submodule", "update", "--init"] + submodules, str(repo_dir)
@@ -99,20 +101,47 @@ def clone_or_update(
             file_timestamp = Path(repo_dir / ".git" / "HEAD")
         age = datetime.now() - datetime.fromtimestamp(file_timestamp.stat().st_mtime)
         if refresh is None or age.total_seconds() > refresh.total_seconds:
-            old_sha = run_git_command(["git", "rev-parse", "HEAD"], str(repo_dir))
-            _LOGGER.info("Updating %s", key)
-            _LOGGER.debug("Location: %s", repo_dir)
-            # Stash local changes (if any)
-            run_git_command(
-                ["git", "stash", "push", "--include-untracked"], str(repo_dir)
-            )
-            # Fetch remote ref
-            cmd = ["git", "fetch", "--", "origin"]
-            if ref is not None:
-                cmd.append(ref)
-            run_git_command(cmd, str(repo_dir))
-            # Hard reset to FETCH_HEAD (short-lived git ref corresponding to most recent fetch)
-            run_git_command(["git", "reset", "--hard", "FETCH_HEAD"], str(repo_dir))
+            # Try to update the repository, recovering from broken state if needed
+            old_sha: str | None = None
+            try:
+                old_sha = run_git_command(["git", "rev-parse", "HEAD"], str(repo_dir))
+                _LOGGER.info("Updating %s", key)
+                _LOGGER.debug("Location: %s", repo_dir)
+                # Stash local changes (if any)
+                run_git_command(
+                    ["git", "stash", "push", "--include-untracked"], str(repo_dir)
+                )
+                # Fetch remote ref
+                cmd = ["git", "fetch", "--", "origin"]
+                if ref is not None:
+                    cmd.append(ref)
+                run_git_command(cmd, str(repo_dir))
+                # Hard reset to FETCH_HEAD (short-lived git ref corresponding to most recent fetch)
+                run_git_command(["git", "reset", "--hard", "FETCH_HEAD"], str(repo_dir))
+            except cv.Invalid as err:
+                # Repository is in a broken state or update failed
+                # Only attempt recovery once to prevent infinite recursion
+                if not _recover_broken:
+                    raise
+
+                _LOGGER.warning(
+                    "Repository %s has issues (%s), removing and re-cloning",
+                    key,
+                    err,
+                )
+                shutil.rmtree(repo_dir)
+                # Recursively call clone_or_update to re-clone
+                # Set _recover_broken=False to prevent infinite recursion
+                return clone_or_update(
+                    url=url,
+                    ref=ref,
+                    refresh=refresh,
+                    domain=domain,
+                    username=username,
+                    password=password,
+                    submodules=submodules,
+                    _recover_broken=False,
+                )
 
             if submodules is not None:
                 _LOGGER.info(
diff --git a/tests/unit_tests/test_git.py b/tests/unit_tests/test_git.py
index 6a51206ec2..748d384018 100644
--- a/tests/unit_tests/test_git.py
+++ b/tests/unit_tests/test_git.py
@@ -6,7 +6,10 @@ import os
 from pathlib import Path
 from unittest.mock import Mock
 
+import pytest
+
 from esphome import git
+import esphome.config_validation as cv
 from esphome.core import CORE, TimePeriodSeconds
 
 
@@ -244,3 +247,160 @@ def test_clone_or_update_with_none_refresh_always_updates(
         if len(call[0]) > 0 and "fetch" in call[0][0]
     ]
     assert len(fetch_calls) > 0
+
+
+@pytest.mark.parametrize(
+    ("fail_command", "error_message"),
+    [
+        (
+            "rev-parse",
+            "ambiguous argument 'HEAD': unknown revision or path not in the working tree.",
+        ),
+        ("stash", "fatal: unable to write new index file"),
+        (
+            "fetch",
+            "fatal: unable to access 'https://github.com/test/repo/': Could not resolve host",
+        ),
+        ("reset", "fatal: Could not reset index file to revision 'FETCH_HEAD'"),
+    ],
+)
+def test_clone_or_update_recovers_from_git_failures(
+    tmp_path: Path, mock_run_git_command: Mock, fail_command: str, error_message: str
+) -> None:
+    """Test that repos are re-cloned when various git commands fail."""
+    # Set up CORE.config_path so data_dir uses tmp_path
+    CORE.config_path = tmp_path / "test.yaml"
+
+    url = "https://github.com/test/repo"
+    ref = "main"
+    key = f"{url}@{ref}"
+    domain = "test"
+
+    h = hashlib.new("sha256")
+    h.update(key.encode())
+    repo_dir = tmp_path / ".esphome" / domain / h.hexdigest()[:8]
+
+    # Create repo directory
+    repo_dir.mkdir(parents=True)
+    git_dir = repo_dir / ".git"
+    git_dir.mkdir()
+
+    fetch_head = git_dir / "FETCH_HEAD"
+    fetch_head.write_text("test")
+    old_time = datetime.now() - timedelta(days=2)
+    fetch_head.touch()
+    os.utime(fetch_head, (old_time.timestamp(), old_time.timestamp()))
+
+    # Track command call counts to make first call fail, subsequent calls succeed
+    call_counts: dict[str, int] = {}
+
+    def git_command_side_effect(cmd: list[str], cwd: str | None = None) -> str:
+        # Determine which command this is
+        cmd_type = None
+        if "rev-parse" in cmd:
+            cmd_type = "rev-parse"
+        elif "stash" in cmd:
+            cmd_type = "stash"
+        elif "fetch" in cmd:
+            cmd_type = "fetch"
+        elif "reset" in cmd:
+            cmd_type = "reset"
+        elif "clone" in cmd:
+            cmd_type = "clone"
+
+        # Track call count for this command type
+        if cmd_type:
+            call_counts[cmd_type] = call_counts.get(cmd_type, 0) + 1
+
+        # Fail on first call to the specified command, succeed on subsequent calls
+        if cmd_type == fail_command and call_counts[cmd_type] == 1:
+            raise cv.Invalid(error_message)
+
+        # Default successful responses
+        if cmd_type == "rev-parse":
+            return "abc123"
+        return ""
+
+    mock_run_git_command.side_effect = git_command_side_effect
+
+    refresh = TimePeriodSeconds(days=1)
+    result_dir, revert = git.clone_or_update(
+        url=url,
+        ref=ref,
+        refresh=refresh,
+        domain=domain,
+    )
+
+    # Verify recovery happened
+    call_list = mock_run_git_command.call_args_list
+
+    # Should have attempted the failing command
+    assert any(fail_command in str(c) for c in call_list)
+
+    # Should have called clone for recovery
+    assert any("clone" in str(c) for c in call_list)
+
+    # Verify the repo directory path is returned
+    assert result_dir == repo_dir
+
+
+def test_clone_or_update_fails_when_recovery_also_fails(
+    tmp_path: Path, mock_run_git_command: Mock
+) -> None:
+    """Test that we don't infinitely recurse when recovery also fails."""
+    # Set up CORE.config_path so data_dir uses tmp_path
+    CORE.config_path = tmp_path / "test.yaml"
+
+    url = "https://github.com/test/repo"
+    ref = "main"
+    key = f"{url}@{ref}"
+    domain = "test"
+
+    h = hashlib.new("sha256")
+    h.update(key.encode())
+    repo_dir = tmp_path / ".esphome" / domain / h.hexdigest()[:8]
+
+    # Create repo directory
+    repo_dir.mkdir(parents=True)
+    git_dir = repo_dir / ".git"
+    git_dir.mkdir()
+
+    fetch_head = git_dir / "FETCH_HEAD"
+    fetch_head.write_text("test")
+    old_time = datetime.now() - timedelta(days=2)
+    fetch_head.touch()
+    os.utime(fetch_head, (old_time.timestamp(), old_time.timestamp()))
+
+    # Mock git command to fail on clone (simulating network failure during recovery)
+    def git_command_side_effect(cmd: list[str], cwd: str | None = None) -> str:
+        if "rev-parse" in cmd:
+            # First time fails (broken repo)
+            raise cv.Invalid(
+                "ambiguous argument 'HEAD': unknown revision or path not in the working tree."
+            )
+        if "clone" in cmd:
+            # Clone also fails (recovery fails)
+            raise cv.Invalid("fatal: unable to access repository")
+        return ""
+
+    mock_run_git_command.side_effect = git_command_side_effect
+
+    refresh = TimePeriodSeconds(days=1)
+
+    # Should raise after one recovery attempt fails
+    with pytest.raises(cv.Invalid, match="fatal: unable to access repository"):
+        git.clone_or_update(
+            url=url,
+            ref=ref,
+            refresh=refresh,
+            domain=domain,
+        )
+
+    # Verify we only tried to clone once (no infinite recursion)
+    call_list = mock_run_git_command.call_args_list
+    clone_calls = [c for c in call_list if "clone" in c[0][0]]
+    # Should have exactly one clone call (the recovery attempt that failed)
+    assert len(clone_calls) == 1
+    # Should have tried rev-parse once (which failed and triggered recovery)
+    rev_parse_calls = [c for c in call_list if "rev-parse" in c[0][0]]
+    assert len(rev_parse_calls) == 1