diff --git a/esphome/components/api/api.proto b/esphome/components/api/api.proto
index 4d0c4a6db0..c1f0142017 100644
--- a/esphome/components/api/api.proto
+++ b/esphome/components/api/api.proto
@@ -308,6 +308,12 @@ enum EntityCategory {
   ENTITY_CATEGORY_DIAGNOSTIC = 2;
 }
 
+// Entity field max_data_length values match constants in esphome/core/config.py:
+//   name/object_id = 120 (NAME_MAX_LENGTH)
+//   icon = 63 (ICON_MAX_LENGTH)
+//   device_class = 47 (DEVICE_CLASS_MAX_LENGTH)
+//   unit_of_measurement = 63 (UNIT_OF_MEASUREMENT_MAX_LENGTH)
+
 // ==================== BINARY SENSOR ====================
 message ListEntitiesBinarySensorResponse {
   option (id) = 12;
@@ -315,15 +321,15 @@ message ListEntitiesBinarySensorResponse {
   option (source) = SOURCE_SERVER;
   option (ifdef) = "USE_BINARY_SENSOR";
 
-  string object_id = 1;
+  string object_id = 1 [(max_data_length) = 120, (force) = true];
   fixed32 key = 2 [(force) = true];
-  string name = 3;
+  string name = 3 [(max_data_length) = 120, (force) = true];
   reserved 4; // Deprecated: was string unique_id
 
-  string device_class = 5;
+  string device_class = 5 [(max_data_length) = 47];
   bool is_status_binary_sensor = 6;
   bool disabled_by_default = 7;
-  string icon = 8 [(field_ifdef) = "USE_ENTITY_ICON"];
+  string icon = 8 [(field_ifdef) = "USE_ENTITY_ICON", (max_data_length) = 63];
   EntityCategory entity_category = 9;
   uint32 device_id = 10 [(field_ifdef) = "USE_DEVICES"];
 }
@@ -349,17 +355,17 @@ message ListEntitiesCoverResponse {
   option (source) = SOURCE_SERVER;
   option (ifdef) = "USE_COVER";
 
-  string object_id = 1;
+  string object_id = 1 [(max_data_length) = 120, (force) = true];
   fixed32 key = 2 [(force) = true];
-  string name = 3;
+  string name = 3 [(max_data_length) = 120, (force) = true];
   reserved 4; // Deprecated: was string unique_id
 
   bool assumed_state = 5;
   bool supports_position = 6;
   bool supports_tilt = 7;
-  string device_class = 8;
+  string device_class = 8 [(max_data_length) = 47];
   bool disabled_by_default = 9;
-  string icon = 10 [(field_ifdef) = "USE_ENTITY_ICON"];
+  string icon = 10 [(field_ifdef) = "USE_ENTITY_ICON", (max_data_length) = 63];
   EntityCategory entity_category = 11;
   bool supports_stop = 12;
   uint32 device_id = 13 [(field_ifdef) = "USE_DEVICES"];
@@ -433,9 +439,9 @@ message ListEntitiesFanResponse {
   option (source) = SOURCE_SERVER;
   option (ifdef) = "USE_FAN";
 
-  string object_id = 1;
+  string object_id = 1 [(max_data_length) = 120, (force) = true];
   fixed32 key = 2 [(force) = true];
-  string name = 3;
+  string name = 3 [(max_data_length) = 120, (force) = true];
   reserved 4; // Deprecated: was string unique_id
 
   bool supports_oscillation = 5;
@@ -443,7 +449,7 @@ message ListEntitiesFanResponse {
   bool supports_direction = 7;
   int32 supported_speed_count = 8;
   bool disabled_by_default = 9;
-  string icon = 10 [(field_ifdef) = "USE_ENTITY_ICON"];
+  string icon = 10 [(field_ifdef) = "USE_ENTITY_ICON", (max_data_length) = 63];
   EntityCategory entity_category = 11;
   repeated string supported_preset_modes = 12 [(container_pointer_no_template) = "std::vector<const char *>"];
   uint32 device_id = 13 [(field_ifdef) = "USE_DEVICES"];
@@ -521,9 +527,9 @@ message ListEntitiesLightResponse {
   option (source) = SOURCE_SERVER;
   option (ifdef) = "USE_LIGHT";
 
-  string object_id = 1;
+  string object_id = 1 [(max_data_length) = 120, (force) = true];
   fixed32 key = 2 [(force) = true];
-  string name = 3;
+  string name = 3 [(max_data_length) = 120, (force) = true];
   reserved 4; // Deprecated: was string unique_id
 
   repeated ColorMode supported_color_modes = 12 [(container_pointer_no_template) = "light::ColorModeMask"];
@@ -540,7 +546,7 @@ message ListEntitiesLightResponse {
   float max_mireds = 10;
   repeated string effects = 11 [(container_pointer_no_template) = "FixedVector<const char *>"];
   bool disabled_by_default = 13;
-  string icon = 14 [(field_ifdef) = "USE_ENTITY_ICON"];
+  string icon = 14 [(field_ifdef) = "USE_ENTITY_ICON", (max_data_length) = 63];
   EntityCategory entity_category = 15;
   uint32 device_id = 16 [(field_ifdef) = "USE_DEVICES"];
 }
@@ -626,16 +632,16 @@ message ListEntitiesSensorResponse {
   option (source) = SOURCE_SERVER;
   option (ifdef) = "USE_SENSOR";
 
-  string object_id = 1;
+  string object_id = 1 [(max_data_length) = 120, (force) = true];
   fixed32 key = 2 [(force) = true];
-  string name = 3;
+  string name = 3 [(max_data_length) = 120, (force) = true];
   reserved 4; // Deprecated: was string unique_id
 
-  string icon = 5 [(field_ifdef) = "USE_ENTITY_ICON"];
-  string unit_of_measurement = 6;
+  string icon = 5 [(field_ifdef) = "USE_ENTITY_ICON", (max_data_length) = 63];
+  string unit_of_measurement = 6 [(max_data_length) = 63];
   int32 accuracy_decimals = 7;
   bool force_update = 8;
-  string device_class = 9;
+  string device_class = 9 [(max_data_length) = 47];
   SensorStateClass state_class = 10;
   // Last reset type removed in 2021.9.0
   // Deprecated in API version 1.5
@@ -666,16 +672,16 @@ message ListEntitiesSwitchResponse {
   option (source) = SOURCE_SERVER;
   option (ifdef) = "USE_SWITCH";
 
-  string object_id = 1;
+  string object_id = 1 [(max_data_length) = 120, (force) = true];
   fixed32 key = 2 [(force) = true];
-  string name = 3;
+  string name = 3 [(max_data_length) = 120, (force) = true];
   reserved 4; // Deprecated: was string unique_id
 
-  string icon = 5 [(field_ifdef) = "USE_ENTITY_ICON"];
+  string icon = 5 [(field_ifdef) = "USE_ENTITY_ICON", (max_data_length) = 63];
   bool assumed_state = 6;
   bool disabled_by_default = 7;
   EntityCategory entity_category = 8;
-  string device_class = 9;
+  string device_class = 9 [(max_data_length) = 47];
   uint32 device_id = 10 [(field_ifdef) = "USE_DEVICES"];
 }
 message SwitchStateResponse {
@@ -708,15 +714,15 @@ message ListEntitiesTextSensorResponse {
   option (source) = SOURCE_SERVER;
   option (ifdef) = "USE_TEXT_SENSOR";
 
-  string object_id = 1;
+  string object_id = 1 [(max_data_length) = 120, (force) = true];
   fixed32 key = 2 [(force) = true];
-  string name = 3;
+  string name = 3 [(max_data_length) = 120, (force) = true];
   reserved 4; // Deprecated: was string unique_id
 
-  string icon = 5 [(field_ifdef) = "USE_ENTITY_ICON"];
+  string icon = 5 [(field_ifdef) = "USE_ENTITY_ICON", (max_data_length) = 63];
   bool disabled_by_default = 6;
   EntityCategory entity_category = 7;
-  string device_class = 8;
+  string device_class = 8 [(max_data_length) = 47];
   uint32 device_id = 9 [(field_ifdef) = "USE_DEVICES"];
 }
 message TextSensorStateResponse {
@@ -971,12 +977,12 @@ message ListEntitiesCameraResponse {
   option (source) = SOURCE_SERVER;
   option (ifdef) = "USE_CAMERA";
 
-  string object_id = 1;
+  string object_id = 1 [(max_data_length) = 120, (force) = true];
   fixed32 key = 2 [(force) = true];
-  string name = 3;
+  string name = 3 [(max_data_length) = 120, (force) = true];
   reserved 4; // Deprecated: was string unique_id
   bool disabled_by_default = 5;
-  string icon = 6 [(field_ifdef) = "USE_ENTITY_ICON"];
+  string icon = 6 [(field_ifdef) = "USE_ENTITY_ICON", (max_data_length) = 63];
   EntityCategory entity_category = 7;
   uint32 device_id = 8 [(field_ifdef) = "USE_DEVICES"];
 }
@@ -1056,9 +1062,9 @@ message ListEntitiesClimateResponse {
   option (source) = SOURCE_SERVER;
   option (ifdef) = "USE_CLIMATE";
 
-  string object_id = 1;
+  string object_id = 1 [(max_data_length) = 120, (force) = true];
   fixed32 key = 2 [(force) = true];
-  string name = 3;
+  string name = 3 [(max_data_length) = 120, (force) = true];
   reserved 4; // Deprecated: was string unique_id
 
   bool supports_current_temperature = 5; // Deprecated: use feature_flags
@@ -1078,7 +1084,7 @@ message ListEntitiesClimateResponse {
   repeated ClimatePreset supported_presets = 16 [(container_pointer_no_template) = "climate::ClimatePresetMask"];
   repeated string supported_custom_presets = 17 [(container_pointer_no_template) = "std::vector<const char *>"];
   bool disabled_by_default = 18;
-  string icon = 19 [(field_ifdef) = "USE_ENTITY_ICON"];
+  string icon = 19 [(field_ifdef) = "USE_ENTITY_ICON", (max_data_length) = 63];
   EntityCategory entity_category = 20;
   float visual_current_temperature_step = 21;
   bool supports_current_humidity = 22; // Deprecated: use feature_flags
@@ -1167,10 +1173,10 @@ message ListEntitiesWaterHeaterResponse {
   option (source) = SOURCE_SERVER;
   option (ifdef) = "USE_WATER_HEATER";
 
-  string object_id = 1;
+  string object_id = 1 [(max_data_length) = 120, (force) = true];
   fixed32 key = 2 [(force) = true];
-  string name = 3;
-  string icon = 4 [(field_ifdef) = "USE_ENTITY_ICON"];
+  string name = 3 [(max_data_length) = 120, (force) = true];
+  string icon = 4 [(field_ifdef) = "USE_ENTITY_ICON", (max_data_length) = 63];
   bool disabled_by_default = 5;
   EntityCategory entity_category = 6;
   uint32 device_id = 7 [(field_ifdef) = "USE_DEVICES"];
@@ -1243,12 +1249,12 @@ message ListEntitiesNumberResponse {
   option (source) = SOURCE_SERVER;
   option (ifdef) = "USE_NUMBER";
 
-  string object_id = 1;
+  string object_id = 1 [(max_data_length) = 120, (force) = true];
   fixed32 key = 2 [(force) = true];
-  string name = 3;
+  string name = 3 [(max_data_length) = 120, (force) = true];
   reserved 4; // Deprecated: was string unique_id
 
-  string icon = 5 [(field_ifdef) = "USE_ENTITY_ICON"];
+  string icon = 5 [(field_ifdef) = "USE_ENTITY_ICON", (max_data_length) = 63];
   float min_value = 6;
   float max_value = 7;
   float step = 8;
@@ -1256,7 +1262,7 @@ message ListEntitiesNumberResponse {
   EntityCategory entity_category = 10;
   string unit_of_measurement = 11;
   NumberMode mode = 12;
-  string device_class = 13;
+  string device_class = 13 [(max_data_length) = 47];
   uint32 device_id = 14 [(field_ifdef) = "USE_DEVICES"];
 }
 message NumberStateResponse {
@@ -1292,12 +1298,12 @@ message ListEntitiesSelectResponse {
   option (source) = SOURCE_SERVER;
   option (ifdef) = "USE_SELECT";
 
-  string object_id = 1;
+  string object_id = 1 [(max_data_length) = 120, (force) = true];
   fixed32 key = 2 [(force) = true];
-  string name = 3;
+  string name = 3 [(max_data_length) = 120, (force) = true];
   reserved 4; // Deprecated: was string unique_id
 
-  string icon = 5 [(field_ifdef) = "USE_ENTITY_ICON"];
+  string icon = 5 [(field_ifdef) = "USE_ENTITY_ICON", (max_data_length) = 63];
   repeated string options = 6 [(container_pointer_no_template) = "FixedVector<const char *>"];
   bool disabled_by_default = 7;
   EntityCategory entity_category = 8;
@@ -1336,12 +1342,12 @@ message ListEntitiesSirenResponse {
   option (source) = SOURCE_SERVER;
   option (ifdef) = "USE_SIREN";
 
-  string object_id = 1;
+  string object_id = 1 [(max_data_length) = 120, (force) = true];
   fixed32 key = 2 [(force) = true];
-  string name = 3;
+  string name = 3 [(max_data_length) = 120, (force) = true];
   reserved 4; // Deprecated: was string unique_id
 
-  string icon = 5 [(field_ifdef) = "USE_ENTITY_ICON"];
+  string icon = 5 [(field_ifdef) = "USE_ENTITY_ICON", (max_data_length) = 63];
   bool disabled_by_default = 6;
   repeated string tones = 7 [(container_pointer_no_template) = "FixedVector<const char *>"];
   bool supports_duration = 8;
@@ -1399,12 +1405,12 @@ message ListEntitiesLockResponse {
   option (source) = SOURCE_SERVER;
   option (ifdef) = "USE_LOCK";
 
-  string object_id = 1;
+  string object_id = 1 [(max_data_length) = 120, (force) = true];
   fixed32 key = 2 [(force) = true];
-  string name = 3;
+  string name = 3 [(max_data_length) = 120, (force) = true];
   reserved 4; // Deprecated: was string unique_id
 
-  string icon = 5 [(field_ifdef) = "USE_ENTITY_ICON"];
+  string icon = 5 [(field_ifdef) = "USE_ENTITY_ICON", (max_data_length) = 63];
   bool disabled_by_default = 6;
   EntityCategory entity_category = 7;
   bool assumed_state = 8;
@@ -1448,15 +1454,15 @@ message ListEntitiesButtonResponse {
   option (source) = SOURCE_SERVER;
   option (ifdef) = "USE_BUTTON";
 
-  string object_id = 1;
+  string object_id = 1 [(max_data_length) = 120, (force) = true];
   fixed32 key = 2 [(force) = true];
-  string name = 3;
+  string name = 3 [(max_data_length) = 120, (force) = true];
   reserved 4; // Deprecated: was string unique_id
 
-  string icon = 5 [(field_ifdef) = "USE_ENTITY_ICON"];
+  string icon = 5 [(field_ifdef) = "USE_ENTITY_ICON", (max_data_length) = 63];
   bool disabled_by_default = 6;
   EntityCategory entity_category = 7;
-  string device_class = 8;
+  string device_class = 8 [(max_data_length) = 47];
   uint32 device_id = 9 [(field_ifdef) = "USE_DEVICES"];
 }
 message ButtonCommandRequest {
@@ -1515,12 +1521,12 @@ message ListEntitiesMediaPlayerResponse {
   option (source) = SOURCE_SERVER;
   option (ifdef) = "USE_MEDIA_PLAYER";
 
-  string object_id = 1;
+  string object_id = 1 [(max_data_length) = 120, (force) = true];
   fixed32 key = 2 [(force) = true];
-  string name = 3;
+  string name = 3 [(max_data_length) = 120, (force) = true];
   reserved 4; // Deprecated: was string unique_id
 
-  string icon = 5 [(field_ifdef) = "USE_ENTITY_ICON"];
+  string icon = 5 [(field_ifdef) = "USE_ENTITY_ICON", (max_data_length) = 63];
   bool disabled_by_default = 6;
   EntityCategory entity_category = 7;
 
@@ -1606,7 +1612,7 @@ message BluetoothLEAdvertisementResponse {
 message BluetoothLERawAdvertisement {
   uint64 address = 1 [(force) = true];
   sint32 rssi = 2 [(force) = true];
-  uint32 address_type = 3;
+  uint32 address_type = 3 [(max_value) = 4];
 
   bytes data = 4 [(fixed_array_size) = 62, (force) = true];
 }
@@ -2103,11 +2109,11 @@ message ListEntitiesAlarmControlPanelResponse {
   option (source) = SOURCE_SERVER;
   option (ifdef) = "USE_ALARM_CONTROL_PANEL";
 
-  string object_id = 1;
+  string object_id = 1 [(max_data_length) = 120, (force) = true];
   fixed32 key = 2 [(force) = true];
-  string name = 3;
+  string name = 3 [(max_data_length) = 120, (force) = true];
   reserved 4; // Deprecated: was string unique_id
-  string icon = 5 [(field_ifdef) = "USE_ENTITY_ICON"];
+  string icon = 5 [(field_ifdef) = "USE_ENTITY_ICON", (max_data_length) = 63];
   bool disabled_by_default = 6;
   EntityCategory entity_category = 7;
   uint32 supported_features = 8;
@@ -2150,11 +2156,11 @@ message ListEntitiesTextResponse {
   option (source) = SOURCE_SERVER;
   option (ifdef) = "USE_TEXT";
 
-  string object_id = 1;
+  string object_id = 1 [(max_data_length) = 120, (force) = true];
   fixed32 key = 2 [(force) = true];
-  string name = 3;
+  string name = 3 [(max_data_length) = 120, (force) = true];
   reserved 4; // Deprecated: was string unique_id
-  string icon = 5 [(field_ifdef) = "USE_ENTITY_ICON"];
+  string icon = 5 [(field_ifdef) = "USE_ENTITY_ICON", (max_data_length) = 63];
   bool disabled_by_default = 6;
   EntityCategory entity_category = 7;
 
@@ -2198,12 +2204,12 @@ message ListEntitiesDateResponse {
   option (source) = SOURCE_SERVER;
   option (ifdef) = "USE_DATETIME_DATE";
 
-  string object_id = 1;
+  string object_id = 1 [(max_data_length) = 120, (force) = true];
   fixed32 key = 2 [(force) = true];
-  string name = 3;
+  string name = 3 [(max_data_length) = 120, (force) = true];
   reserved 4; // Deprecated: was string unique_id
 
-  string icon = 5 [(field_ifdef) = "USE_ENTITY_ICON"];
+  string icon = 5 [(field_ifdef) = "USE_ENTITY_ICON", (max_data_length) = 63];
   bool disabled_by_default = 6;
   EntityCategory entity_category = 7;
   uint32 device_id = 8 [(field_ifdef) = "USE_DEVICES"];
@@ -2245,12 +2251,12 @@ message ListEntitiesTimeResponse {
   option (source) = SOURCE_SERVER;
   option (ifdef) = "USE_DATETIME_TIME";
 
-  string object_id = 1;
+  string object_id = 1 [(max_data_length) = 120, (force) = true];
   fixed32 key = 2 [(force) = true];
-  string name = 3;
+  string name = 3 [(max_data_length) = 120, (force) = true];
   reserved 4; // Deprecated: was string unique_id
 
-  string icon = 5 [(field_ifdef) = "USE_ENTITY_ICON"];
+  string icon = 5 [(field_ifdef) = "USE_ENTITY_ICON", (max_data_length) = 63];
   bool disabled_by_default = 6;
   EntityCategory entity_category = 7;
   uint32 device_id = 8 [(field_ifdef) = "USE_DEVICES"];
@@ -2292,15 +2298,15 @@ message ListEntitiesEventResponse {
   option (source) = SOURCE_SERVER;
   option (ifdef) = "USE_EVENT";
 
-  string object_id = 1;
+  string object_id = 1 [(max_data_length) = 120, (force) = true];
   fixed32 key = 2 [(force) = true];
-  string name = 3;
+  string name = 3 [(max_data_length) = 120, (force) = true];
   reserved 4; // Deprecated: was string unique_id
 
-  string icon = 5 [(field_ifdef) = "USE_ENTITY_ICON"];
+  string icon = 5 [(field_ifdef) = "USE_ENTITY_ICON", (max_data_length) = 63];
   bool disabled_by_default = 6;
   EntityCategory entity_category = 7;
-  string device_class = 8;
+  string device_class = 8 [(max_data_length) = 47];
 
   repeated string event_types = 9 [(container_pointer_no_template) = "FixedVector<const char *>"];
   uint32 device_id = 10 [(field_ifdef) = "USE_DEVICES"];
@@ -2323,15 +2329,15 @@ message ListEntitiesValveResponse {
   option (source) = SOURCE_SERVER;
   option (ifdef) = "USE_VALVE";
 
-  string object_id = 1;
+  string object_id = 1 [(max_data_length) = 120, (force) = true];
   fixed32 key = 2 [(force) = true];
-  string name = 3;
+  string name = 3 [(max_data_length) = 120, (force) = true];
   reserved 4; // Deprecated: was string unique_id
 
-  string icon = 5 [(field_ifdef) = "USE_ENTITY_ICON"];
+  string icon = 5 [(field_ifdef) = "USE_ENTITY_ICON", (max_data_length) = 63];
   bool disabled_by_default = 6;
   EntityCategory entity_category = 7;
-  string device_class = 8;
+  string device_class = 8 [(max_data_length) = 47];
 
   bool assumed_state = 9;
   bool supports_position = 10;
@@ -2378,12 +2384,12 @@ message ListEntitiesDateTimeResponse {
   option (source) = SOURCE_SERVER;
   option (ifdef) = "USE_DATETIME_DATETIME";
 
-  string object_id = 1;
+  string object_id = 1 [(max_data_length) = 120, (force) = true];
   fixed32 key = 2 [(force) = true];
-  string name = 3;
+  string name = 3 [(max_data_length) = 120, (force) = true];
   reserved 4; // Deprecated: was string unique_id
 
-  string icon = 5 [(field_ifdef) = "USE_ENTITY_ICON"];
+  string icon = 5 [(field_ifdef) = "USE_ENTITY_ICON", (max_data_length) = 63];
   bool disabled_by_default = 6;
   EntityCategory entity_category = 7;
   uint32 device_id = 8 [(field_ifdef) = "USE_DEVICES"];
@@ -2421,15 +2427,15 @@ message ListEntitiesUpdateResponse {
   option (source) = SOURCE_SERVER;
   option (ifdef) = "USE_UPDATE";
 
-  string object_id = 1;
+  string object_id = 1 [(max_data_length) = 120, (force) = true];
   fixed32 key = 2 [(force) = true];
-  string name = 3;
+  string name = 3 [(max_data_length) = 120, (force) = true];
   reserved 4; // Deprecated: was string unique_id
 
-  string icon = 5 [(field_ifdef) = "USE_ENTITY_ICON"];
+  string icon = 5 [(field_ifdef) = "USE_ENTITY_ICON", (max_data_length) = 63];
   bool disabled_by_default = 6;
   EntityCategory entity_category = 7;
-  string device_class = 8;
+  string device_class = 8 [(max_data_length) = 47];
   uint32 device_id = 9 [(field_ifdef) = "USE_DEVICES"];
 }
 message UpdateStateResponse {
@@ -2504,10 +2510,10 @@ message ListEntitiesInfraredResponse {
   option (source) = SOURCE_SERVER;
   option (ifdef) = "USE_INFRARED";
 
-  string object_id = 1;
+  string object_id = 1 [(max_data_length) = 120, (force) = true];
   fixed32 key = 2 [(force) = true];
-  string name = 3;
-  string icon = 4 [(field_ifdef) = "USE_ENTITY_ICON"];
+  string name = 3 [(max_data_length) = 120, (force) = true];
+  string icon = 4 [(field_ifdef) = "USE_ENTITY_ICON", (max_data_length) = 63];
   bool disabled_by_default = 5;
   EntityCategory entity_category = 6;
   uint32 device_id = 7 [(field_ifdef) = "USE_DEVICES"];
diff --git a/esphome/components/api/api_options.proto b/esphome/components/api/api_options.proto
index 02600f0977..0f71268d70 100644
--- a/esphome/components/api/api_options.proto
+++ b/esphome/components/api/api_options.proto
@@ -96,4 +96,16 @@ extend google.protobuf.FieldOptions {
     // variant of the calc_ method. Use on fields that are almost always non-default
     // to eliminate dead branches on hot paths.
     optional bool force = 50016 [default=false];
+
+    // max_value: Maximum value a field can have.
+    // When max_value < 128, the code generator emits constant-size calculations
+    // and direct byte writes instead of varint branching, since the encoded varint
+    // is guaranteed to be 1 byte.
+    optional uint32 max_value = 50017;
+
+    // max_data_length: Maximum length of a string or bytes field.
+    // When max_data_length < 128, the code generator emits constant-size
+    // length varint calculations and direct byte writes, since the length
+    // varint is guaranteed to be 1 byte.
+    optional uint32 max_data_length = 50018;
 }
diff --git a/esphome/components/api/api_pb2.cpp b/esphome/components/api/api_pb2.cpp
index b979650078..98bea30628 100644
--- a/esphome/components/api/api_pb2.cpp
+++ b/esphome/components/api/api_pb2.cpp
@@ -207,9 +207,9 @@ uint32_t DeviceInfoResponse::calculate_size() const {
 }
 #ifdef USE_BINARY_SENSOR
 void ListEntitiesBinarySensorResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_string(1, this->object_id);
+  buffer.write_short_string(10, this->object_id);
   buffer.write_tag_and_fixed32(21, this->key);
-  buffer.encode_string(3, this->name);
+  buffer.write_short_string(26, this->name);
   buffer.encode_string(5, this->device_class);
   buffer.encode_bool(6, this->is_status_binary_sensor);
   buffer.encode_bool(7, this->disabled_by_default);
@@ -223,14 +223,14 @@ void ListEntitiesBinarySensorResponse::encode(ProtoWriteBuffer &buffer) const {
 }
 uint32_t ListEntitiesBinarySensorResponse::calculate_size() const {
   uint32_t size = 0;
-  size += ProtoSize::calc_length(1, this->object_id.size());
+  size += 2 + this->object_id.size();
   size += 5;
-  size += ProtoSize::calc_length(1, this->name.size());
-  size += ProtoSize::calc_length(1, this->device_class.size());
+  size += 2 + this->name.size();
+  size += !this->device_class.empty() ? 2 + this->device_class.size() : 0;
   size += ProtoSize::calc_bool(1, this->is_status_binary_sensor);
   size += ProtoSize::calc_bool(1, this->disabled_by_default);
 #ifdef USE_ENTITY_ICON
-  size += ProtoSize::calc_length(1, this->icon.size());
+  size += !this->icon.empty() ? 2 + this->icon.size() : 0;
 #endif
   size += ProtoSize::calc_uint32(1, static_cast<uint32_t>(this->entity_category));
 #ifdef USE_DEVICES
@@ -259,9 +259,9 @@ uint32_t BinarySensorStateResponse::calculate_size() const {
 #endif
 #ifdef USE_COVER
 void ListEntitiesCoverResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_string(1, this->object_id);
+  buffer.write_short_string(10, this->object_id);
   buffer.write_tag_and_fixed32(21, this->key);
-  buffer.encode_string(3, this->name);
+  buffer.write_short_string(26, this->name);
   buffer.encode_bool(5, this->assumed_state);
   buffer.encode_bool(6, this->supports_position);
   buffer.encode_bool(7, this->supports_tilt);
@@ -278,16 +278,16 @@ void ListEntitiesCoverResponse::encode(ProtoWriteBuffer &buffer) const {
 }
 uint32_t ListEntitiesCoverResponse::calculate_size() const {
   uint32_t size = 0;
-  size += ProtoSize::calc_length(1, this->object_id.size());
+  size += 2 + this->object_id.size();
   size += 5;
-  size += ProtoSize::calc_length(1, this->name.size());
+  size += 2 + this->name.size();
   size += ProtoSize::calc_bool(1, this->assumed_state);
   size += ProtoSize::calc_bool(1, this->supports_position);
   size += ProtoSize::calc_bool(1, this->supports_tilt);
-  size += ProtoSize::calc_length(1, this->device_class.size());
+  size += !this->device_class.empty() ? 2 + this->device_class.size() : 0;
   size += ProtoSize::calc_bool(1, this->disabled_by_default);
 #ifdef USE_ENTITY_ICON
-  size += ProtoSize::calc_length(1, this->icon.size());
+  size += !this->icon.empty() ? 2 + this->icon.size() : 0;
 #endif
   size += ProtoSize::calc_uint32(1, static_cast<uint32_t>(this->entity_category));
   size += ProtoSize::calc_bool(1, this->supports_stop);
@@ -356,9 +356,9 @@ bool CoverCommandRequest::decode_32bit(uint32_t field_id, Proto32Bit value) {
 #endif
 #ifdef USE_FAN
 void ListEntitiesFanResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_string(1, this->object_id);
+  buffer.write_short_string(10, this->object_id);
   buffer.write_tag_and_fixed32(21, this->key);
-  buffer.encode_string(3, this->name);
+  buffer.write_short_string(26, this->name);
   buffer.encode_bool(5, this->supports_oscillation);
   buffer.encode_bool(6, this->supports_speed);
   buffer.encode_bool(7, this->supports_direction);
@@ -377,16 +377,16 @@ void ListEntitiesFanResponse::encode(ProtoWriteBuffer &buffer) const {
 }
 uint32_t ListEntitiesFanResponse::calculate_size() const {
   uint32_t size = 0;
-  size += ProtoSize::calc_length(1, this->object_id.size());
+  size += 2 + this->object_id.size();
   size += 5;
-  size += ProtoSize::calc_length(1, this->name.size());
+  size += 2 + this->name.size();
   size += ProtoSize::calc_bool(1, this->supports_oscillation);
   size += ProtoSize::calc_bool(1, this->supports_speed);
   size += ProtoSize::calc_bool(1, this->supports_direction);
   size += ProtoSize::calc_int32(1, this->supported_speed_count);
   size += ProtoSize::calc_bool(1, this->disabled_by_default);
 #ifdef USE_ENTITY_ICON
-  size += ProtoSize::calc_length(1, this->icon.size());
+  size += !this->icon.empty() ? 2 + this->icon.size() : 0;
 #endif
   size += ProtoSize::calc_uint32(1, static_cast<uint32_t>(this->entity_category));
   if (!this->supported_preset_modes->empty()) {
@@ -486,9 +486,9 @@ bool FanCommandRequest::decode_32bit(uint32_t field_id, Proto32Bit value) {
 #endif
 #ifdef USE_LIGHT
 void ListEntitiesLightResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_string(1, this->object_id);
+  buffer.write_short_string(10, this->object_id);
   buffer.write_tag_and_fixed32(21, this->key);
-  buffer.encode_string(3, this->name);
+  buffer.write_short_string(26, this->name);
   for (const auto &it : *this->supported_color_modes) {
     buffer.encode_uint32(12, static_cast<uint32_t>(it), true);
   }
@@ -508,9 +508,9 @@ void ListEntitiesLightResponse::encode(ProtoWriteBuffer &buffer) const {
 }
 uint32_t ListEntitiesLightResponse::calculate_size() const {
   uint32_t size = 0;
-  size += ProtoSize::calc_length(1, this->object_id.size());
+  size += 2 + this->object_id.size();
   size += 5;
-  size += ProtoSize::calc_length(1, this->name.size());
+  size += 2 + this->name.size();
   if (!this->supported_color_modes->empty()) {
     for (const auto &it : *this->supported_color_modes) {
       size += ProtoSize::calc_uint32_force(1, static_cast<uint32_t>(it));
@@ -525,7 +525,7 @@ uint32_t ListEntitiesLightResponse::calculate_size() const {
   }
   size += ProtoSize::calc_bool(1, this->disabled_by_default);
 #ifdef USE_ENTITY_ICON
-  size += ProtoSize::calc_length(1, this->icon.size());
+  size += !this->icon.empty() ? 2 + this->icon.size() : 0;
 #endif
   size += ProtoSize::calc_uint32(1, static_cast<uint32_t>(this->entity_category));
 #ifdef USE_DEVICES
@@ -682,9 +682,9 @@ bool LightCommandRequest::decode_32bit(uint32_t field_id, Proto32Bit value) {
 #endif
 #ifdef USE_SENSOR
 void ListEntitiesSensorResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_string(1, this->object_id);
+  buffer.write_short_string(10, this->object_id);
   buffer.write_tag_and_fixed32(21, this->key);
-  buffer.encode_string(3, this->name);
+  buffer.write_short_string(26, this->name);
 #ifdef USE_ENTITY_ICON
   buffer.encode_string(5, this->icon);
 #endif
@@ -701,16 +701,16 @@ void ListEntitiesSensorResponse::encode(ProtoWriteBuffer &buffer) const {
 }
 uint32_t ListEntitiesSensorResponse::calculate_size() const {
   uint32_t size = 0;
-  size += ProtoSize::calc_length(1, this->object_id.size());
+  size += 2 + this->object_id.size();
   size += 5;
-  size += ProtoSize::calc_length(1, this->name.size());
+  size += 2 + this->name.size();
 #ifdef USE_ENTITY_ICON
-  size += ProtoSize::calc_length(1, this->icon.size());
+  size += !this->icon.empty() ? 2 + this->icon.size() : 0;
 #endif
-  size += ProtoSize::calc_length(1, this->unit_of_measurement.size());
+  size += !this->unit_of_measurement.empty() ? 2 + this->unit_of_measurement.size() : 0;
   size += ProtoSize::calc_int32(1, this->accuracy_decimals);
   size += ProtoSize::calc_bool(1, this->force_update);
-  size += ProtoSize::calc_length(1, this->device_class.size());
+  size += !this->device_class.empty() ? 2 + this->device_class.size() : 0;
   size += ProtoSize::calc_uint32(1, static_cast<uint32_t>(this->state_class));
   size += ProtoSize::calc_bool(1, this->disabled_by_default);
   size += ProtoSize::calc_uint32(1, static_cast<uint32_t>(this->entity_category));
@@ -740,9 +740,9 @@ uint32_t SensorStateResponse::calculate_size() const {
 #endif
 #ifdef USE_SWITCH
 void ListEntitiesSwitchResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_string(1, this->object_id);
+  buffer.write_short_string(10, this->object_id);
   buffer.write_tag_and_fixed32(21, this->key);
-  buffer.encode_string(3, this->name);
+  buffer.write_short_string(26, this->name);
 #ifdef USE_ENTITY_ICON
   buffer.encode_string(5, this->icon);
 #endif
@@ -756,16 +756,16 @@ void ListEntitiesSwitchResponse::encode(ProtoWriteBuffer &buffer) const {
 }
 uint32_t ListEntitiesSwitchResponse::calculate_size() const {
   uint32_t size = 0;
-  size += ProtoSize::calc_length(1, this->object_id.size());
+  size += 2 + this->object_id.size();
   size += 5;
-  size += ProtoSize::calc_length(1, this->name.size());
+  size += 2 + this->name.size();
 #ifdef USE_ENTITY_ICON
-  size += ProtoSize::calc_length(1, this->icon.size());
+  size += !this->icon.empty() ? 2 + this->icon.size() : 0;
 #endif
   size += ProtoSize::calc_bool(1, this->assumed_state);
   size += ProtoSize::calc_bool(1, this->disabled_by_default);
   size += ProtoSize::calc_uint32(1, static_cast<uint32_t>(this->entity_category));
-  size += ProtoSize::calc_length(1, this->device_class.size());
+  size += !this->device_class.empty() ? 2 + this->device_class.size() : 0;
 #ifdef USE_DEVICES
   size += ProtoSize::calc_uint32(1, this->device_id);
 #endif
@@ -815,9 +815,9 @@ bool SwitchCommandRequest::decode_32bit(uint32_t field_id, Proto32Bit value) {
 #endif
 #ifdef USE_TEXT_SENSOR
 void ListEntitiesTextSensorResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_string(1, this->object_id);
+  buffer.write_short_string(10, this->object_id);
   buffer.write_tag_and_fixed32(21, this->key);
-  buffer.encode_string(3, this->name);
+  buffer.write_short_string(26, this->name);
 #ifdef USE_ENTITY_ICON
   buffer.encode_string(5, this->icon);
 #endif
@@ -830,15 +830,15 @@ void ListEntitiesTextSensorResponse::encode(ProtoWriteBuffer &buffer) const {
 }
 uint32_t ListEntitiesTextSensorResponse::calculate_size() const {
   uint32_t size = 0;
-  size += ProtoSize::calc_length(1, this->object_id.size());
+  size += 2 + this->object_id.size();
   size += 5;
-  size += ProtoSize::calc_length(1, this->name.size());
+  size += 2 + this->name.size();
 #ifdef USE_ENTITY_ICON
-  size += ProtoSize::calc_length(1, this->icon.size());
+  size += !this->icon.empty() ? 2 + this->icon.size() : 0;
 #endif
   size += ProtoSize::calc_bool(1, this->disabled_by_default);
   size += ProtoSize::calc_uint32(1, static_cast<uint32_t>(this->entity_category));
-  size += ProtoSize::calc_length(1, this->device_class.size());
+  size += !this->device_class.empty() ? 2 + this->device_class.size() : 0;
 #ifdef USE_DEVICES
   size += ProtoSize::calc_uint32(1, this->device_id);
 #endif
@@ -1264,9 +1264,9 @@ uint32_t ExecuteServiceResponse::calculate_size() const {
 #endif
 #ifdef USE_CAMERA
 void ListEntitiesCameraResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_string(1, this->object_id);
+  buffer.write_short_string(10, this->object_id);
   buffer.write_tag_and_fixed32(21, this->key);
-  buffer.encode_string(3, this->name);
+  buffer.write_short_string(26, this->name);
   buffer.encode_bool(5, this->disabled_by_default);
 #ifdef USE_ENTITY_ICON
   buffer.encode_string(6, this->icon);
@@ -1278,12 +1278,12 @@ void ListEntitiesCameraResponse::encode(ProtoWriteBuffer &buffer) const {
 }
 uint32_t ListEntitiesCameraResponse::calculate_size() const {
   uint32_t size = 0;
-  size += ProtoSize::calc_length(1, this->object_id.size());
+  size += 2 + this->object_id.size();
   size += 5;
-  size += ProtoSize::calc_length(1, this->name.size());
+  size += 2 + this->name.size();
   size += ProtoSize::calc_bool(1, this->disabled_by_default);
 #ifdef USE_ENTITY_ICON
-  size += ProtoSize::calc_length(1, this->icon.size());
+  size += !this->icon.empty() ? 2 + this->icon.size() : 0;
 #endif
   size += ProtoSize::calc_uint32(1, static_cast<uint32_t>(this->entity_category));
 #ifdef USE_DEVICES
@@ -1325,9 +1325,9 @@ bool CameraImageRequest::decode_varint(uint32_t field_id, proto_varint_value_t v
 #endif
 #ifdef USE_CLIMATE
 void ListEntitiesClimateResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_string(1, this->object_id);
+  buffer.write_short_string(10, this->object_id);
   buffer.write_tag_and_fixed32(21, this->key);
-  buffer.encode_string(3, this->name);
+  buffer.write_short_string(26, this->name);
   buffer.encode_bool(5, this->supports_current_temperature);
   buffer.encode_bool(6, this->supports_two_point_target_temperature);
   for (const auto &it : *this->supported_modes) {
@@ -1369,9 +1369,9 @@ void ListEntitiesClimateResponse::encode(ProtoWriteBuffer &buffer) const {
 }
 uint32_t ListEntitiesClimateResponse::calculate_size() const {
   uint32_t size = 0;
-  size += ProtoSize::calc_length(1, this->object_id.size());
+  size += 2 + this->object_id.size();
   size += 5;
-  size += ProtoSize::calc_length(1, this->name.size());
+  size += 2 + this->name.size();
   size += ProtoSize::calc_bool(1, this->supports_current_temperature);
   size += ProtoSize::calc_bool(1, this->supports_two_point_target_temperature);
   if (!this->supported_modes->empty()) {
@@ -1410,7 +1410,7 @@ uint32_t ListEntitiesClimateResponse::calculate_size() const {
   }
   size += ProtoSize::calc_bool(2, this->disabled_by_default);
 #ifdef USE_ENTITY_ICON
-  size += ProtoSize::calc_length(2, this->icon.size());
+  size += !this->icon.empty() ? 3 + this->icon.size() : 0;
 #endif
   size += ProtoSize::calc_uint32(2, static_cast<uint32_t>(this->entity_category));
   size += ProtoSize::calc_float(2, this->visual_current_temperature_step);
@@ -1558,9 +1558,9 @@ bool ClimateCommandRequest::decode_32bit(uint32_t field_id, Proto32Bit value) {
 #endif
 #ifdef USE_WATER_HEATER
 void ListEntitiesWaterHeaterResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_string(1, this->object_id);
+  buffer.write_short_string(10, this->object_id);
   buffer.write_tag_and_fixed32(21, this->key);
-  buffer.encode_string(3, this->name);
+  buffer.write_short_string(26, this->name);
 #ifdef USE_ENTITY_ICON
   buffer.encode_string(4, this->icon);
 #endif
@@ -1579,11 +1579,11 @@ void ListEntitiesWaterHeaterResponse::encode(ProtoWriteBuffer &buffer) const {
 }
 uint32_t ListEntitiesWaterHeaterResponse::calculate_size() const {
   uint32_t size = 0;
-  size += ProtoSize::calc_length(1, this->object_id.size());
+  size += 2 + this->object_id.size();
   size += 5;
-  size += ProtoSize::calc_length(1, this->name.size());
+  size += 2 + this->name.size();
 #ifdef USE_ENTITY_ICON
-  size += ProtoSize::calc_length(1, this->icon.size());
+  size += !this->icon.empty() ? 2 + this->icon.size() : 0;
 #endif
   size += ProtoSize::calc_bool(1, this->disabled_by_default);
   size += ProtoSize::calc_uint32(1, static_cast<uint32_t>(this->entity_category));
@@ -1670,9 +1670,9 @@ bool WaterHeaterCommandRequest::decode_32bit(uint32_t field_id, Proto32Bit value
 #endif
 #ifdef USE_NUMBER
 void ListEntitiesNumberResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_string(1, this->object_id);
+  buffer.write_short_string(10, this->object_id);
   buffer.write_tag_and_fixed32(21, this->key);
-  buffer.encode_string(3, this->name);
+  buffer.write_short_string(26, this->name);
 #ifdef USE_ENTITY_ICON
   buffer.encode_string(5, this->icon);
 #endif
@@ -1690,11 +1690,11 @@ void ListEntitiesNumberResponse::encode(ProtoWriteBuffer &buffer) const {
 }
 uint32_t ListEntitiesNumberResponse::calculate_size() const {
   uint32_t size = 0;
-  size += ProtoSize::calc_length(1, this->object_id.size());
+  size += 2 + this->object_id.size();
   size += 5;
-  size += ProtoSize::calc_length(1, this->name.size());
+  size += 2 + this->name.size();
 #ifdef USE_ENTITY_ICON
-  size += ProtoSize::calc_length(1, this->icon.size());
+  size += !this->icon.empty() ? 2 + this->icon.size() : 0;
 #endif
   size += ProtoSize::calc_float(1, this->min_value);
   size += ProtoSize::calc_float(1, this->max_value);
@@ -1703,7 +1703,7 @@ uint32_t ListEntitiesNumberResponse::calculate_size() const {
   size += ProtoSize::calc_uint32(1, static_cast<uint32_t>(this->entity_category));
   size += ProtoSize::calc_length(1, this->unit_of_measurement.size());
   size += ProtoSize::calc_uint32(1, static_cast<uint32_t>(this->mode));
-  size += ProtoSize::calc_length(1, this->device_class.size());
+  size += !this->device_class.empty() ? 2 + this->device_class.size() : 0;
 #ifdef USE_DEVICES
   size += ProtoSize::calc_uint32(1, this->device_id);
 #endif
@@ -1755,9 +1755,9 @@ bool NumberCommandRequest::decode_32bit(uint32_t field_id, Proto32Bit value) {
 #endif
 #ifdef USE_SELECT
 void ListEntitiesSelectResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_string(1, this->object_id);
+  buffer.write_short_string(10, this->object_id);
   buffer.write_tag_and_fixed32(21, this->key);
-  buffer.encode_string(3, this->name);
+  buffer.write_short_string(26, this->name);
 #ifdef USE_ENTITY_ICON
   buffer.encode_string(5, this->icon);
 #endif
@@ -1772,11 +1772,11 @@ void ListEntitiesSelectResponse::encode(ProtoWriteBuffer &buffer) const {
 }
 uint32_t ListEntitiesSelectResponse::calculate_size() const {
   uint32_t size = 0;
-  size += ProtoSize::calc_length(1, this->object_id.size());
+  size += 2 + this->object_id.size();
   size += 5;
-  size += ProtoSize::calc_length(1, this->name.size());
+  size += 2 + this->name.size();
 #ifdef USE_ENTITY_ICON
-  size += ProtoSize::calc_length(1, this->icon.size());
+  size += !this->icon.empty() ? 2 + this->icon.size() : 0;
 #endif
   if (!this->options->empty()) {
     for (const char *it : *this->options) {
@@ -1844,9 +1844,9 @@ bool SelectCommandRequest::decode_32bit(uint32_t field_id, Proto32Bit value) {
 #endif
 #ifdef USE_SIREN
 void ListEntitiesSirenResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_string(1, this->object_id);
+  buffer.write_short_string(10, this->object_id);
   buffer.write_tag_and_fixed32(21, this->key);
-  buffer.encode_string(3, this->name);
+  buffer.write_short_string(26, this->name);
 #ifdef USE_ENTITY_ICON
   buffer.encode_string(5, this->icon);
 #endif
@@ -1863,11 +1863,11 @@ void ListEntitiesSirenResponse::encode(ProtoWriteBuffer &buffer) const {
 }
 uint32_t ListEntitiesSirenResponse::calculate_size() const {
   uint32_t size = 0;
-  size += ProtoSize::calc_length(1, this->object_id.size());
+  size += 2 + this->object_id.size();
   size += 5;
-  size += ProtoSize::calc_length(1, this->name.size());
+  size += 2 + this->name.size();
 #ifdef USE_ENTITY_ICON
-  size += ProtoSize::calc_length(1, this->icon.size());
+  size += !this->icon.empty() ? 2 + this->icon.size() : 0;
 #endif
   size += ProtoSize::calc_bool(1, this->disabled_by_default);
   if (!this->tones->empty()) {
@@ -1956,9 +1956,9 @@ bool SirenCommandRequest::decode_32bit(uint32_t field_id, Proto32Bit value) {
 #endif
 #ifdef USE_LOCK
 void ListEntitiesLockResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_string(1, this->object_id);
+  buffer.write_short_string(10, this->object_id);
   buffer.write_tag_and_fixed32(21, this->key);
-  buffer.encode_string(3, this->name);
+  buffer.write_short_string(26, this->name);
 #ifdef USE_ENTITY_ICON
   buffer.encode_string(5, this->icon);
 #endif
@@ -1974,11 +1974,11 @@ void ListEntitiesLockResponse::encode(ProtoWriteBuffer &buffer) const {
 }
 uint32_t ListEntitiesLockResponse::calculate_size() const {
   uint32_t size = 0;
-  size += ProtoSize::calc_length(1, this->object_id.size());
+  size += 2 + this->object_id.size();
   size += 5;
-  size += ProtoSize::calc_length(1, this->name.size());
+  size += 2 + this->name.size();
 #ifdef USE_ENTITY_ICON
-  size += ProtoSize::calc_length(1, this->icon.size());
+  size += !this->icon.empty() ? 2 + this->icon.size() : 0;
 #endif
   size += ProtoSize::calc_bool(1, this->disabled_by_default);
   size += ProtoSize::calc_uint32(1, static_cast<uint32_t>(this->entity_category));
@@ -2049,9 +2049,9 @@ bool LockCommandRequest::decode_32bit(uint32_t field_id, Proto32Bit value) {
 #endif
 #ifdef USE_BUTTON
 void ListEntitiesButtonResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_string(1, this->object_id);
+  buffer.write_short_string(10, this->object_id);
   buffer.write_tag_and_fixed32(21, this->key);
-  buffer.encode_string(3, this->name);
+  buffer.write_short_string(26, this->name);
 #ifdef USE_ENTITY_ICON
   buffer.encode_string(5, this->icon);
 #endif
@@ -2064,15 +2064,15 @@ void ListEntitiesButtonResponse::encode(ProtoWriteBuffer &buffer) const {
 }
 uint32_t ListEntitiesButtonResponse::calculate_size() const {
   uint32_t size = 0;
-  size += ProtoSize::calc_length(1, this->object_id.size());
+  size += 2 + this->object_id.size();
   size += 5;
-  size += ProtoSize::calc_length(1, this->name.size());
+  size += 2 + this->name.size();
 #ifdef USE_ENTITY_ICON
-  size += ProtoSize::calc_length(1, this->icon.size());
+  size += !this->icon.empty() ? 2 + this->icon.size() : 0;
 #endif
   size += ProtoSize::calc_bool(1, this->disabled_by_default);
   size += ProtoSize::calc_uint32(1, static_cast<uint32_t>(this->entity_category));
-  size += ProtoSize::calc_length(1, this->device_class.size());
+  size += !this->device_class.empty() ? 2 + this->device_class.size() : 0;
 #ifdef USE_DEVICES
   size += ProtoSize::calc_uint32(1, this->device_id);
 #endif
@@ -2119,9 +2119,9 @@ uint32_t MediaPlayerSupportedFormat::calculate_size() const {
   return size;
 }
 void ListEntitiesMediaPlayerResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_string(1, this->object_id);
+  buffer.write_short_string(10, this->object_id);
   buffer.write_tag_and_fixed32(21, this->key);
-  buffer.encode_string(3, this->name);
+  buffer.write_short_string(26, this->name);
 #ifdef USE_ENTITY_ICON
   buffer.encode_string(5, this->icon);
 #endif
@@ -2138,11 +2138,11 @@ void ListEntitiesMediaPlayerResponse::encode(ProtoWriteBuffer &buffer) const {
 }
 uint32_t ListEntitiesMediaPlayerResponse::calculate_size() const {
   uint32_t size = 0;
-  size += ProtoSize::calc_length(1, this->object_id.size());
+  size += 2 + this->object_id.size();
   size += 5;
-  size += ProtoSize::calc_length(1, this->name.size());
+  size += 2 + this->name.size();
 #ifdef USE_ENTITY_ICON
-  size += ProtoSize::calc_length(1, this->icon.size());
+  size += !this->icon.empty() ? 2 + this->icon.size() : 0;
 #endif
   size += ProtoSize::calc_bool(1, this->disabled_by_default);
   size += ProtoSize::calc_uint32(1, static_cast<uint32_t>(this->entity_category));
@@ -2251,15 +2251,15 @@ void BluetoothLERawAdvertisement::encode(ProtoWriteBuffer &buffer) const {
   buffer.encode_varint_raw_short(encode_zigzag32(this->rssi));
   buffer.encode_uint32(3, this->address_type);
   buffer.write_raw_byte(34);
-  buffer.encode_varint_raw(this->data_len);
+  buffer.write_raw_byte(static_cast<uint8_t>(this->data_len));
   buffer.encode_raw(this->data, this->data_len);
 }
 uint32_t BluetoothLERawAdvertisement::calculate_size() const {
   uint32_t size = 0;
   size += ProtoSize::calc_uint64_force(1, this->address);
   size += ProtoSize::calc_sint32_force(1, this->rssi);
-  size += ProtoSize::calc_uint32(1, this->address_type);
-  size += ProtoSize::calc_length_force(1, this->data_len);
+  size += this->address_type ? 2 : 0;
+  size += 2 + this->data_len;
   return size;
 }
 void BluetoothLERawAdvertisementsResponse::encode(ProtoWriteBuffer &buffer) const {
@@ -2941,9 +2941,9 @@ bool VoiceAssistantSetConfiguration::decode_length(uint32_t field_id, ProtoLengt
 #endif
 #ifdef USE_ALARM_CONTROL_PANEL
 void ListEntitiesAlarmControlPanelResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_string(1, this->object_id);
+  buffer.write_short_string(10, this->object_id);
   buffer.write_tag_and_fixed32(21, this->key);
-  buffer.encode_string(3, this->name);
+  buffer.write_short_string(26, this->name);
 #ifdef USE_ENTITY_ICON
   buffer.encode_string(5, this->icon);
 #endif
@@ -2958,11 +2958,11 @@ void ListEntitiesAlarmControlPanelResponse::encode(ProtoWriteBuffer &buffer) con
 }
 uint32_t ListEntitiesAlarmControlPanelResponse::calculate_size() const {
   uint32_t size = 0;
-  size += ProtoSize::calc_length(1, this->object_id.size());
+  size += 2 + this->object_id.size();
   size += 5;
-  size += ProtoSize::calc_length(1, this->name.size());
+  size += 2 + this->name.size();
 #ifdef USE_ENTITY_ICON
-  size += ProtoSize::calc_length(1, this->icon.size());
+  size += !this->icon.empty() ? 2 + this->icon.size() : 0;
 #endif
   size += ProtoSize::calc_bool(1, this->disabled_by_default);
   size += ProtoSize::calc_uint32(1, static_cast<uint32_t>(this->entity_category));
@@ -3029,9 +3029,9 @@ bool AlarmControlPanelCommandRequest::decode_32bit(uint32_t field_id, Proto32Bit
 #endif
 #ifdef USE_TEXT
 void ListEntitiesTextResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_string(1, this->object_id);
+  buffer.write_short_string(10, this->object_id);
   buffer.write_tag_and_fixed32(21, this->key);
-  buffer.encode_string(3, this->name);
+  buffer.write_short_string(26, this->name);
 #ifdef USE_ENTITY_ICON
   buffer.encode_string(5, this->icon);
 #endif
@@ -3047,11 +3047,11 @@ void ListEntitiesTextResponse::encode(ProtoWriteBuffer &buffer) const {
 }
 uint32_t ListEntitiesTextResponse::calculate_size() const {
   uint32_t size = 0;
-  size += ProtoSize::calc_length(1, this->object_id.size());
+  size += 2 + this->object_id.size();
   size += 5;
-  size += ProtoSize::calc_length(1, this->name.size());
+  size += 2 + this->name.size();
 #ifdef USE_ENTITY_ICON
-  size += ProtoSize::calc_length(1, this->icon.size());
+  size += !this->icon.empty() ? 2 + this->icon.size() : 0;
 #endif
   size += ProtoSize::calc_bool(1, this->disabled_by_default);
   size += ProtoSize::calc_uint32(1, static_cast<uint32_t>(this->entity_category));
@@ -3118,9 +3118,9 @@ bool TextCommandRequest::decode_32bit(uint32_t field_id, Proto32Bit value) {
 #endif
 #ifdef USE_DATETIME_DATE
 void ListEntitiesDateResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_string(1, this->object_id);
+  buffer.write_short_string(10, this->object_id);
   buffer.write_tag_and_fixed32(21, this->key);
-  buffer.encode_string(3, this->name);
+  buffer.write_short_string(26, this->name);
 #ifdef USE_ENTITY_ICON
   buffer.encode_string(5, this->icon);
 #endif
@@ -3132,11 +3132,11 @@ void ListEntitiesDateResponse::encode(ProtoWriteBuffer &buffer) const {
 }
 uint32_t ListEntitiesDateResponse::calculate_size() const {
   uint32_t size = 0;
-  size += ProtoSize::calc_length(1, this->object_id.size());
+  size += 2 + this->object_id.size();
   size += 5;
-  size += ProtoSize::calc_length(1, this->name.size());
+  size += 2 + this->name.size();
 #ifdef USE_ENTITY_ICON
-  size += ProtoSize::calc_length(1, this->icon.size());
+  size += !this->icon.empty() ? 2 + this->icon.size() : 0;
 #endif
   size += ProtoSize::calc_bool(1, this->disabled_by_default);
   size += ProtoSize::calc_uint32(1, static_cast<uint32_t>(this->entity_category));
@@ -3201,9 +3201,9 @@ bool DateCommandRequest::decode_32bit(uint32_t field_id, Proto32Bit value) {
 #endif
 #ifdef USE_DATETIME_TIME
 void ListEntitiesTimeResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_string(1, this->object_id);
+  buffer.write_short_string(10, this->object_id);
   buffer.write_tag_and_fixed32(21, this->key);
-  buffer.encode_string(3, this->name);
+  buffer.write_short_string(26, this->name);
 #ifdef USE_ENTITY_ICON
   buffer.encode_string(5, this->icon);
 #endif
@@ -3215,11 +3215,11 @@ void ListEntitiesTimeResponse::encode(ProtoWriteBuffer &buffer) const {
 }
 uint32_t ListEntitiesTimeResponse::calculate_size() const {
   uint32_t size = 0;
-  size += ProtoSize::calc_length(1, this->object_id.size());
+  size += 2 + this->object_id.size();
   size += 5;
-  size += ProtoSize::calc_length(1, this->name.size());
+  size += 2 + this->name.size();
 #ifdef USE_ENTITY_ICON
-  size += ProtoSize::calc_length(1, this->icon.size());
+  size += !this->icon.empty() ? 2 + this->icon.size() : 0;
 #endif
   size += ProtoSize::calc_bool(1, this->disabled_by_default);
   size += ProtoSize::calc_uint32(1, static_cast<uint32_t>(this->entity_category));
@@ -3284,9 +3284,9 @@ bool TimeCommandRequest::decode_32bit(uint32_t field_id, Proto32Bit value) {
 #endif
 #ifdef USE_EVENT
 void ListEntitiesEventResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_string(1, this->object_id);
+  buffer.write_short_string(10, this->object_id);
   buffer.write_tag_and_fixed32(21, this->key);
-  buffer.encode_string(3, this->name);
+  buffer.write_short_string(26, this->name);
 #ifdef USE_ENTITY_ICON
   buffer.encode_string(5, this->icon);
 #endif
@@ -3302,15 +3302,15 @@ void ListEntitiesEventResponse::encode(ProtoWriteBuffer &buffer) const {
 }
 uint32_t ListEntitiesEventResponse::calculate_size() const {
   uint32_t size = 0;
-  size += ProtoSize::calc_length(1, this->object_id.size());
+  size += 2 + this->object_id.size();
   size += 5;
-  size += ProtoSize::calc_length(1, this->name.size());
+  size += 2 + this->name.size();
 #ifdef USE_ENTITY_ICON
-  size += ProtoSize::calc_length(1, this->icon.size());
+  size += !this->icon.empty() ? 2 + this->icon.size() : 0;
 #endif
   size += ProtoSize::calc_bool(1, this->disabled_by_default);
   size += ProtoSize::calc_uint32(1, static_cast<uint32_t>(this->entity_category));
-  size += ProtoSize::calc_length(1, this->device_class.size());
+  size += !this->device_class.empty() ? 2 + this->device_class.size() : 0;
   if (!this->event_types->empty()) {
     for (const char *it : *this->event_types) {
       size += ProtoSize::calc_length_force(1, strlen(it));
@@ -3340,9 +3340,9 @@ uint32_t EventResponse::calculate_size() const {
 #endif
 #ifdef USE_VALVE
 void ListEntitiesValveResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_string(1, this->object_id);
+  buffer.write_short_string(10, this->object_id);
   buffer.write_tag_and_fixed32(21, this->key);
-  buffer.encode_string(3, this->name);
+  buffer.write_short_string(26, this->name);
 #ifdef USE_ENTITY_ICON
   buffer.encode_string(5, this->icon);
 #endif
@@ -3358,15 +3358,15 @@ void ListEntitiesValveResponse::encode(ProtoWriteBuffer &buffer) const {
 }
 uint32_t ListEntitiesValveResponse::calculate_size() const {
   uint32_t size = 0;
-  size += ProtoSize::calc_length(1, this->object_id.size());
+  size += 2 + this->object_id.size();
   size += 5;
-  size += ProtoSize::calc_length(1, this->name.size());
+  size += 2 + this->name.size();
 #ifdef USE_ENTITY_ICON
-  size += ProtoSize::calc_length(1, this->icon.size());
+  size += !this->icon.empty() ? 2 + this->icon.size() : 0;
 #endif
   size += ProtoSize::calc_bool(1, this->disabled_by_default);
   size += ProtoSize::calc_uint32(1, static_cast<uint32_t>(this->entity_category));
-  size += ProtoSize::calc_length(1, this->device_class.size());
+  size += !this->device_class.empty() ? 2 + this->device_class.size() : 0;
   size += ProtoSize::calc_bool(1, this->assumed_state);
   size += ProtoSize::calc_bool(1, this->supports_position);
   size += ProtoSize::calc_bool(1, this->supports_stop);
@@ -3427,9 +3427,9 @@ bool ValveCommandRequest::decode_32bit(uint32_t field_id, Proto32Bit value) {
 #endif
 #ifdef USE_DATETIME_DATETIME
 void ListEntitiesDateTimeResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_string(1, this->object_id);
+  buffer.write_short_string(10, this->object_id);
   buffer.write_tag_and_fixed32(21, this->key);
-  buffer.encode_string(3, this->name);
+  buffer.write_short_string(26, this->name);
 #ifdef USE_ENTITY_ICON
   buffer.encode_string(5, this->icon);
 #endif
@@ -3441,11 +3441,11 @@ void ListEntitiesDateTimeResponse::encode(ProtoWriteBuffer &buffer) const {
 }
 uint32_t ListEntitiesDateTimeResponse::calculate_size() const {
   uint32_t size = 0;
-  size += ProtoSize::calc_length(1, this->object_id.size());
+  size += 2 + this->object_id.size();
   size += 5;
-  size += ProtoSize::calc_length(1, this->name.size());
+  size += 2 + this->name.size();
 #ifdef USE_ENTITY_ICON
-  size += ProtoSize::calc_length(1, this->icon.size());
+  size += !this->icon.empty() ? 2 + this->icon.size() : 0;
 #endif
   size += ProtoSize::calc_bool(1, this->disabled_by_default);
   size += ProtoSize::calc_uint32(1, static_cast<uint32_t>(this->entity_category));
@@ -3500,9 +3500,9 @@ bool DateTimeCommandRequest::decode_32bit(uint32_t field_id, Proto32Bit value) {
 #endif
 #ifdef USE_UPDATE
 void ListEntitiesUpdateResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_string(1, this->object_id);
+  buffer.write_short_string(10, this->object_id);
   buffer.write_tag_and_fixed32(21, this->key);
-  buffer.encode_string(3, this->name);
+  buffer.write_short_string(26, this->name);
 #ifdef USE_ENTITY_ICON
   buffer.encode_string(5, this->icon);
 #endif
@@ -3515,15 +3515,15 @@ void ListEntitiesUpdateResponse::encode(ProtoWriteBuffer &buffer) const {
 }
 uint32_t ListEntitiesUpdateResponse::calculate_size() const {
   uint32_t size = 0;
-  size += ProtoSize::calc_length(1, this->object_id.size());
+  size += 2 + this->object_id.size();
   size += 5;
-  size += ProtoSize::calc_length(1, this->name.size());
+  size += 2 + this->name.size();
 #ifdef USE_ENTITY_ICON
-  size += ProtoSize::calc_length(1, this->icon.size());
+  size += !this->icon.empty() ? 2 + this->icon.size() : 0;
 #endif
   size += ProtoSize::calc_bool(1, this->disabled_by_default);
   size += ProtoSize::calc_uint32(1, static_cast<uint32_t>(this->entity_category));
-  size += ProtoSize::calc_length(1, this->device_class.size());
+  size += !this->device_class.empty() ? 2 + this->device_class.size() : 0;
 #ifdef USE_DEVICES
   size += ProtoSize::calc_uint32(1, this->device_id);
 #endif
@@ -3641,9 +3641,9 @@ uint32_t ZWaveProxyRequest::calculate_size() const {
 #endif
 #ifdef USE_INFRARED
 void ListEntitiesInfraredResponse::encode(ProtoWriteBuffer &buffer) const {
-  buffer.encode_string(1, this->object_id);
+  buffer.write_short_string(10, this->object_id);
   buffer.write_tag_and_fixed32(21, this->key);
-  buffer.encode_string(3, this->name);
+  buffer.write_short_string(26, this->name);
 #ifdef USE_ENTITY_ICON
   buffer.encode_string(4, this->icon);
 #endif
@@ -3657,11 +3657,11 @@ void ListEntitiesInfraredResponse::encode(ProtoWriteBuffer &buffer) const {
 }
 uint32_t ListEntitiesInfraredResponse::calculate_size() const {
   uint32_t size = 0;
-  size += ProtoSize::calc_length(1, this->object_id.size());
+  size += 2 + this->object_id.size();
   size += 5;
-  size += ProtoSize::calc_length(1, this->name.size());
+  size += 2 + this->name.size();
 #ifdef USE_ENTITY_ICON
-  size += ProtoSize::calc_length(1, this->icon.size());
+  size += !this->icon.empty() ? 2 + this->icon.size() : 0;
 #endif
   size += ProtoSize::calc_bool(1, this->disabled_by_default);
   size += ProtoSize::calc_uint32(1, static_cast<uint32_t>(this->entity_category));
diff --git a/esphome/components/api/proto.h b/esphome/components/api/proto.h
index a3b274df80..4cb5f04fe4 100644
--- a/esphome/components/api/proto.h
+++ b/esphome/components/api/proto.h
@@ -280,6 +280,16 @@ class ProtoWriteBuffer {
     std::memcpy(pos, data, len);
     this->pos_ = pos + len;
   }
+  /// Write tag + 1-byte length + raw string data. For strings with max_data_length < 128.
+  /// Tag must be a single-byte varint (< 128). Always encodes (no zero check).
+  inline void write_short_string(uint8_t tag, const StringRef &ref) ESPHOME_ALWAYS_INLINE {
+    this->debug_check_bounds_(2 + ref.size());
+    uint8_t *__restrict__ pos = this->pos_;
+    *pos++ = tag;
+    *pos++ = static_cast<uint8_t>(ref.size());
+    std::memcpy(pos, ref.c_str(), ref.size());
+    this->pos_ = pos + ref.size();
+  }
   /// Write a precomputed tag byte + 32-bit value in one operation.
   /// Tag must be a single-byte varint (< 128). No zero check.
   inline void write_tag_and_fixed32(uint8_t tag, uint32_t value) ESPHOME_ALWAYS_INLINE {
diff --git a/esphome/components/button/button.cpp b/esphome/components/button/button.cpp
index b1c491805e..2a2a645132 100644
--- a/esphome/components/button/button.cpp
+++ b/esphome/components/button/button.cpp
@@ -16,7 +16,7 @@ void log_button(const char *tag, const char *prefix, const char *type, Button *o
 }
 
 void Button::press() {
-  ESP_LOGD(TAG, "'%s' Pressed.", this->get_name().c_str());
+  ESP_LOGV(TAG, "'%s' Pressed.", this->get_name().c_str());
   this->press_action();
   this->press_callback_.call();
 }
diff --git a/esphome/components/esp32_ble/ble.cpp b/esphome/components/esp32_ble/ble.cpp
index 2cd2ec67f7..68e5fffe2b 100644
--- a/esphome/components/esp32_ble/ble.cpp
+++ b/esphome/components/esp32_ble/ble.cpp
@@ -399,8 +399,17 @@ void ESP32BLE::loop() {
     return;
   }
 
+#ifdef USE_ESP32_BLE_ADVERTISING
+  if (this->advertising_ != nullptr) {
+    this->advertising_->loop();
+  }
+#endif
+
   BLEEvent *ble_event = this->ble_events_.pop();
-  while (ble_event != nullptr) {
+  if (ble_event == nullptr)
+    return;
+
+  do {
     switch (ble_event->type_) {
 #if defined(USE_ESP32_BLE_SERVER) && defined(ESPHOME_ESP32_BLE_GATTS_EVENT_HANDLER_COUNT)
       case BLEEvent::GATTS: {
@@ -488,15 +497,11 @@ void ESP32BLE::loop() {
     }
     // Return the event to the pool
     this->ble_event_pool_.release(ble_event);
-    ble_event = this->ble_events_.pop();
-  }
-#ifdef USE_ESP32_BLE_ADVERTISING
-  if (this->advertising_ != nullptr) {
-    this->advertising_->loop();
-  }
-#endif
+  } while ((ble_event = this->ble_events_.pop()) != nullptr);
 
-  // Log dropped events periodically
+  // Log dropped events - only reachable when events were processed.
+  // Drops only occur when the queue is full, and only this loop drains it,
+  // so if pop() returned nullptr above we can skip this check (saves a memw).
   uint16_t dropped = this->ble_events_.get_and_reset_dropped_count();
   if (dropped > 0) {
     ESP_LOGW(TAG, "Dropped %u BLE events due to buffer overflow", dropped);
diff --git a/esphome/components/hlw8012/hlw8012.cpp b/esphome/components/hlw8012/hlw8012.cpp
index d0fd697d8f..22f292e47e 100644
--- a/esphome/components/hlw8012/hlw8012.cpp
+++ b/esphome/components/hlw8012/hlw8012.cpp
@@ -73,13 +73,13 @@ void HLW8012Component::update() {
     // Only read cf1 after one cycle. Apparently it's quite unstable after being changed.
     if (this->current_mode_) {
       float current = cf1_hz * this->current_multiplier_;
-      ESP_LOGD(TAG, "Got power=%.1fW, current=%.1fA", power, current);
+      ESP_LOGV(TAG, "Got power=%.1fW, current=%.1fA", power, current);
       if (this->current_sensor_ != nullptr) {
         this->current_sensor_->publish_state(current);
       }
     } else {
       float voltage = cf1_hz * this->voltage_multiplier_;
-      ESP_LOGD(TAG, "Got power=%.1fW, voltage=%.1fV", power, voltage);
+      ESP_LOGV(TAG, "Got power=%.1fW, voltage=%.1fV", power, voltage);
       if (this->voltage_sensor_ != nullptr) {
         this->voltage_sensor_->publish_state(voltage);
       }
diff --git a/esphome/components/number/__init__.py b/esphome/components/number/__init__.py
index 90f9fe1835..26d2602ba4 100644
--- a/esphome/components/number/__init__.py
+++ b/esphome/components/number/__init__.py
@@ -79,6 +79,7 @@ from esphome.const import (
     DEVICE_CLASS_WIND_SPEED,
 )
 from esphome.core import CORE, CoroPriority, coroutine_with_priority
+from esphome.core.config import UNIT_OF_MEASUREMENT_MAX_LENGTH
 from esphome.core.entity_helpers import (
     entity_duplicate_validator,
     setup_device_class,
@@ -186,7 +187,11 @@ NUMBER_OPERATION_OPTIONS = {
 }
 
 validate_device_class = cv.one_of(*DEVICE_CLASSES, lower=True, space="_")
-validate_unit_of_measurement = cv.string_strict
+validate_unit_of_measurement = cv.All(
+    cv.string_strict,
+    # Keep in sync with max_data_length in api.proto
+    cv.Length(max=UNIT_OF_MEASUREMENT_MAX_LENGTH),
+)
 
 _NUMBER_SCHEMA = (
     cv.ENTITY_BASE_SCHEMA.extend(web_server.WEBSERVER_SORTING_SCHEMA)
diff --git a/esphome/components/select/select_call.cpp b/esphome/components/select/select_call.cpp
index 0e14371d00..9d2fb725f3 100644
--- a/esphome/components/select/select_call.cpp
+++ b/esphome/components/select/select_call.cpp
@@ -116,7 +116,7 @@ void SelectCall::perform() {
 
   auto idx = target_index.value();
   // All operations use indices, call control() by index to avoid string conversion
-  ESP_LOGD(TAG, "'%s' - Set selected option to: %s", name, parent->option_at(idx));
+  ESP_LOGV(TAG, "'%s' - Set selected option to: %s", name, parent->option_at(idx));
   parent->control(idx);
 }
 
diff --git a/esphome/components/sensor/__init__.py b/esphome/components/sensor/__init__.py
index 626466eefa..275c4542fb 100644
--- a/esphome/components/sensor/__init__.py
+++ b/esphome/components/sensor/__init__.py
@@ -106,6 +106,7 @@ from esphome.const import (
     ENTITY_CATEGORY_CONFIG,
 )
 from esphome.core import CORE, CoroPriority, coroutine_with_priority
+from esphome.core.config import UNIT_OF_MEASUREMENT_MAX_LENGTH
 from esphome.core.entity_helpers import (
     entity_duplicate_validator,
     setup_device_class,
@@ -290,7 +291,11 @@ ClampFilter = sensor_ns.class_("ClampFilter", Filter)
 RoundFilter = sensor_ns.class_("RoundFilter", Filter)
 RoundMultipleFilter = sensor_ns.class_("RoundMultipleFilter", Filter)
 
-validate_unit_of_measurement = cv.string_strict
+validate_unit_of_measurement = cv.All(
+    cv.string_strict,
+    # Keep in sync with max_data_length in api.proto
+    cv.Length(max=UNIT_OF_MEASUREMENT_MAX_LENGTH),
+)
 validate_accuracy_decimals = cv.int_
 validate_icon = cv.icon
 validate_device_class = cv.one_of(*DEVICE_CLASSES, lower=True, space="_")
diff --git a/esphome/components/switch/switch.cpp b/esphome/components/switch/switch.cpp
index 11840db3a3..abc7338a62 100644
--- a/esphome/components/switch/switch.cpp
+++ b/esphome/components/switch/switch.cpp
@@ -18,15 +18,15 @@ void Switch::control(bool target_state) {
   }
 }
 void Switch::turn_on() {
-  ESP_LOGD(TAG, "'%s' Turning ON.", this->get_name().c_str());
+  ESP_LOGV(TAG, "'%s' Turning ON.", this->get_name().c_str());
   this->write_state(!this->inverted_);
 }
 void Switch::turn_off() {
-  ESP_LOGD(TAG, "'%s' Turning OFF.", this->get_name().c_str());
+  ESP_LOGV(TAG, "'%s' Turning OFF.", this->get_name().c_str());
   this->write_state(this->inverted_);
 }
 void Switch::toggle() {
-  ESP_LOGD(TAG, "'%s' Toggling %s.", this->get_name().c_str(), this->state ? "OFF" : "ON");
+  ESP_LOGV(TAG, "'%s' Toggling %s.", this->get_name().c_str(), this->state ? "OFF" : "ON");
   this->write_state(this->inverted_ == this->state);
 }
 optional<bool> Switch::get_initial_state() {
diff --git a/esphome/components/total_daily_energy/total_daily_energy.cpp b/esphome/components/total_daily_energy/total_daily_energy.cpp
index e7a45a5edf..b79df784f6 100644
--- a/esphome/components/total_daily_energy/total_daily_energy.cpp
+++ b/esphome/components/total_daily_energy/total_daily_energy.cpp
@@ -1,10 +1,21 @@
 #include "total_daily_energy.h"
+#include "esphome/core/application.h"
 #include "esphome/core/log.h"
 
-namespace esphome {
-namespace total_daily_energy {
+namespace esphome::total_daily_energy {
 
 static const char *const TAG = "total_daily_energy";
+static constexpr uint32_t TIMEOUT_ID_MIDNIGHT = 1;
+static constexpr uint8_t SECONDS_PER_MINUTE = 60;
+static constexpr uint8_t MINUTES_PER_HOUR = 60;
+static constexpr uint8_t HOURS_PER_DAY = 24;
+static constexpr uint32_t SECONDS_PER_HOUR = SECONDS_PER_MINUTE * MINUTES_PER_HOUR;
+static constexpr uint16_t MILLIS_PER_SECOND = 1000;
+// Wake up 90 minutes before midnight to recalculate, ensuring DST transitions
+// (which shift wall clock by 1 hour but don't change millis()) don't cause
+// the midnight reset to fire late. DST transitions don't trigger the time sync
+// callback since they change local time interpretation, not the epoch.
+static constexpr uint32_t PRE_MIDNIGHT_SECONDS = 90 * SECONDS_PER_MINUTE;
 
 void TotalDailyEnergy::setup() {
   float initial_value = 0;
@@ -15,28 +26,53 @@ void TotalDailyEnergy::setup() {
   }
   this->publish_state_and_save(initial_value);
 
-  this->last_update_ = millis();
+  this->last_update_ = App.get_loop_component_start_time();
 
   this->parent_->add_on_state_callback([this](float state) { this->process_new_state_(state); });
+
+  // Schedule initial midnight reset if time is already valid, otherwise
+  // the time sync callback will handle it once time becomes available.
+  this->schedule_midnight_reset_();
+  // Re-schedule on every NTP sync in case the clock jumped across midnight.
+  this->time_->add_on_time_sync_callback([this]() { this->schedule_midnight_reset_(); });
 }
 
 void TotalDailyEnergy::dump_config() { LOG_SENSOR("", "Total Daily Energy", this); }
 
-void TotalDailyEnergy::loop() {
+void TotalDailyEnergy::schedule_midnight_reset_() {
   auto t = this->time_->now();
   if (!t.is_valid())
     return;
 
-  if (this->last_day_of_year_ == 0) {
+  // Check if the day changed (time sync moved us past midnight, or first call)
+  if (this->last_day_of_year_ != t.day_of_year) {
+    if (this->last_day_of_year_ != 0) {
+      // Day actually changed — reset energy
+      this->total_energy_ = 0;
+      this->publish_state_and_save(0);
+    }
     this->last_day_of_year_ = t.day_of_year;
-    return;
   }
 
-  if (t.day_of_year != this->last_day_of_year_) {
-    this->last_day_of_year_ = t.day_of_year;
-    this->total_energy_ = 0;
-    this->publish_state_and_save(0);
+  // Calculate seconds until next midnight.
+  // Uses the same TIMEOUT_ID_MIDNIGHT ID so re-scheduling (e.g. from time sync) cancels
+  // any previously pending timeout.
+  uint32_t seconds_until_midnight =
+      ((HOURS_PER_DAY - 1 - t.hour) * MINUTES_PER_HOUR + (MINUTES_PER_HOUR - 1 - t.minute)) * SECONDS_PER_MINUTE +
+      (SECONDS_PER_MINUTE - t.second);
+
+  uint32_t timeout_seconds;
+  if (seconds_until_midnight > PRE_MIDNIGHT_SECONDS) {
+    // Far from midnight — wake up 90 minutes before to recalculate with fresh wall clock
+    timeout_seconds = seconds_until_midnight - PRE_MIDNIGHT_SECONDS;
+  } else {
+    // Close to midnight — schedule the actual reset with 1s buffer
+    timeout_seconds = seconds_until_midnight + 1;
   }
+
+  ESP_LOGD(TAG, "Scheduling midnight check in %us", timeout_seconds);
+  this->set_timeout(TIMEOUT_ID_MIDNIGHT, timeout_seconds * MILLIS_PER_SECOND,
+                    [this]() { this->schedule_midnight_reset_(); });
 }
 
 void TotalDailyEnergy::publish_state_and_save(float state) {
@@ -50,14 +86,14 @@ void TotalDailyEnergy::publish_state_and_save(float state) {
 void TotalDailyEnergy::process_new_state_(float state) {
   if (std::isnan(state))
     return;
-  const uint32_t now = millis();
+  const uint32_t now = App.get_loop_component_start_time();
   const float old_state = this->last_power_state_;
   const float new_state = state;
-  float delta_hours = (now - this->last_update_) / 1000.0f / 60.0f / 60.0f;
+  float delta_hours = (now - this->last_update_) / static_cast<float>(MILLIS_PER_SECOND) / SECONDS_PER_HOUR;
   float delta_energy = 0.0f;
   switch (this->method_) {
     case TOTAL_DAILY_ENERGY_METHOD_TRAPEZOID:
-      delta_energy = delta_hours * (old_state + new_state) / 2.0;
+      delta_energy = delta_hours * (old_state + new_state) / 2.0f;
       break;
     case TOTAL_DAILY_ENERGY_METHOD_LEFT:
       delta_energy = delta_hours * old_state;
@@ -71,5 +107,4 @@ void TotalDailyEnergy::process_new_state_(float state) {
   this->publish_state_and_save(this->total_energy_ + delta_energy);
 }
 
-}  // namespace total_daily_energy
-}  // namespace esphome
+}  // namespace esphome::total_daily_energy
diff --git a/esphome/components/total_daily_energy/total_daily_energy.h b/esphome/components/total_daily_energy/total_daily_energy.h
index 1145f54f95..9a20ecea01 100644
--- a/esphome/components/total_daily_energy/total_daily_energy.h
+++ b/esphome/components/total_daily_energy/total_daily_energy.h
@@ -6,8 +6,7 @@
 #include "esphome/components/sensor/sensor.h"
 #include "esphome/components/time/real_time_clock.h"
 
-namespace esphome {
-namespace total_daily_energy {
+namespace esphome::total_daily_energy {
 
 enum TotalDailyEnergyMethod {
   TOTAL_DAILY_ENERGY_METHOD_TRAPEZOID = 0,
@@ -23,12 +22,12 @@ class TotalDailyEnergy : public sensor::Sensor, public Component {
   void set_method(TotalDailyEnergyMethod method) { method_ = method; }
   void setup() override;
   void dump_config() override;
-  void loop() override;
 
   void publish_state_and_save(float state);
 
  protected:
   void process_new_state_(float state);
+  void schedule_midnight_reset_();
 
   ESPPreferenceObject pref_;
   time::RealTimeClock *time_;
@@ -41,5 +40,4 @@ class TotalDailyEnergy : public sensor::Sensor, public Component {
   float last_power_state_{0.0f};
 };
 
-}  // namespace total_daily_energy
-}  // namespace esphome
+}  // namespace esphome::total_daily_energy
diff --git a/esphome/components/wifi/wifi_component_esp_idf.cpp b/esphome/components/wifi/wifi_component_esp_idf.cpp
index 42fff8fd1b..18155726a4 100644
--- a/esphome/components/wifi/wifi_component_esp_idf.cpp
+++ b/esphome/components/wifi/wifi_component_esp_idf.cpp
@@ -717,20 +717,23 @@ const char *get_disconnect_reason_str(uint8_t reason) {
 }
 
 bool WiFiComponent::wifi_loop_() {
-  // Fast path: skip dropped count check and pop loop when queue is empty
-  if (this->event_queue_.empty())
+  // Use pop() directly instead of empty() — pop() costs 1 memw (acquire on tail_),
+  // while empty() costs 2 memw (acquire on both head_ and tail_) on Xtensa.
+  IDFWiFiEvent *data = this->event_queue_.pop();
+  if (data == nullptr)
     return false;
 
+  do {
+    wifi_process_event_(data);
+    delete data;  // NOLINT(cppcoreguidelines-owning-memory)
+  } while ((data = this->event_queue_.pop()) != nullptr);
+
+  // Drops only occur when the queue is full, and only this loop drains it,
+  // so if pop() returned nullptr above we can skip this check.
   uint16_t dropped = this->event_queue_.get_and_reset_dropped_count();
   if (dropped > 0) {
     ESP_LOGW(TAG, "Dropped %u WiFi events due to buffer overflow", dropped);
   }
-
-  IDFWiFiEvent *data;
-  while ((data = this->event_queue_.pop()) != nullptr) {
-    wifi_process_event_(data);
-    delete data;  // NOLINT(cppcoreguidelines-owning-memory)
-  }
   return true;
 }
 // Events are processed from queue in main loop context, but listener notifications
diff --git a/esphome/components/wifi/wifi_component_libretiny.cpp b/esphome/components/wifi/wifi_component_libretiny.cpp
index 7ca3549cab..cdd11ceaef 100644
--- a/esphome/components/wifi/wifi_component_libretiny.cpp
+++ b/esphome/components/wifi/wifi_component_libretiny.cpp
@@ -778,20 +778,24 @@ network::IPAddress WiFiComponent::wifi_subnet_mask_() { return {WiFi.subnetMask(
 network::IPAddress WiFiComponent::wifi_gateway_ip_() { return {WiFi.gatewayIP()}; }
 network::IPAddress WiFiComponent::wifi_dns_ip_(int num) { return {WiFi.dnsIP(num)}; }
 bool WiFiComponent::wifi_loop_() {
-  // Fast path: skip dropped count check and pop loop when queue is empty
-  if (this->event_queue_.empty())
+  // Use pop() directly instead of empty() — avoids redundant synchronization.
+  // LockFreeQueue: pop() costs 1 memw vs empty()'s 2 memw on Xtensa.
+  // FreeRTOSQueue: pop() is 1 critical section vs empty() + pop() = 2.
+  LTWiFiEvent *event = this->event_queue_.pop();
+  if (event == nullptr)
     return false;
 
+  do {
+    wifi_process_event_(event);
+    delete event;  // NOLINT(cppcoreguidelines-owning-memory)
+  } while ((event = this->event_queue_.pop()) != nullptr);
+
+  // Drops only occur when the queue is full, and only this loop drains it,
+  // so if pop() returned nullptr above we can skip this check.
   uint16_t dropped = this->event_queue_.get_and_reset_dropped_count();
   if (dropped > 0) {
     ESP_LOGW(TAG, "Dropped %" PRIu16 " WiFi events due to buffer overflow", dropped);
   }
-
-  LTWiFiEvent *event;
-  while ((event = this->event_queue_.pop()) != nullptr) {
-    wifi_process_event_(event);
-    delete event;  // NOLINT(cppcoreguidelines-owning-memory)
-  }
   return true;
 }
 
diff --git a/esphome/core/config.py b/esphome/core/config.py
index c47693c783..675b9296e5 100644
--- a/esphome/core/config.py
+++ b/esphome/core/config.py
@@ -233,6 +233,9 @@ DEVICE_CLASS_MAX_LENGTH = 47
 # Keep in sync with MAX_ICON_LENGTH in esphome/core/entity_base.h
 ICON_MAX_LENGTH = 63
 
+# Max unit of measurement string length
+UNIT_OF_MEASUREMENT_MAX_LENGTH = 63
+
 AREA_SCHEMA = cv.Schema(
     {
         cv.GenerateID(CONF_ID): cv.declare_id(Area),
diff --git a/esphome/core/entity_helpers.py b/esphome/core/entity_helpers.py
index 0589b92364..fc931c2baa 100644
--- a/esphome/core/entity_helpers.py
+++ b/esphome/core/entity_helpers.py
@@ -17,7 +17,11 @@ from esphome.const import (
     CONF_UNIT_OF_MEASUREMENT,
 )
 from esphome.core import CORE, ID, CoroPriority, coroutine_with_priority
-from esphome.core.config import DEVICE_CLASS_MAX_LENGTH, ICON_MAX_LENGTH
+from esphome.core.config import (
+    DEVICE_CLASS_MAX_LENGTH,
+    ICON_MAX_LENGTH,
+    UNIT_OF_MEASUREMENT_MAX_LENGTH,
+)
 from esphome.cpp_generator import MockObj, RawStatement, add, get_variable
 import esphome.final_validate as fv
 from esphome.helpers import cpp_string_escape, fnv1_hash_object_id, sanitize, snake_case
@@ -200,6 +204,11 @@ def register_device_class(value: str) -> int:
 
 def register_unit_of_measurement(value: str) -> int:
     """Register a unit_of_measurement string and return its 1-based index."""
+    if value and len(value) > UNIT_OF_MEASUREMENT_MAX_LENGTH:
+        raise ValueError(
+            f"Unit of measurement string too long ({len(value)} chars, "
+            f"max {UNIT_OF_MEASUREMENT_MAX_LENGTH}): '{value}'"
+        )
     return _register_string(value, _get_pool().units, _MAX_UNITS, "unit_of_measurement")
 
 
diff --git a/script/api_protobuf/api_protobuf.py b/script/api_protobuf/api_protobuf.py
index 811e7d12d7..260c696dc0 100755
--- a/script/api_protobuf/api_protobuf.py
+++ b/script/api_protobuf/api_protobuf.py
@@ -156,6 +156,16 @@ class TypeInfo(ABC):
         """Check if this field should always be encoded (skip zero/empty check)."""
         return get_field_opt(self._field, pb.force, False)
 
+    @property
+    def max_value(self) -> int | None:
+        """Get the max_value option for this field, or None if not set."""
+        return get_field_opt(self._field, pb.max_value, None)
+
+    @property
+    def max_data_length(self) -> int | None:
+        """Get the max_data_length option for this field, or None if not set."""
+        return get_field_opt(self._field, pb.max_data_length, None)
+
     @property
     def wire_type(self) -> WireType:
         """Get the wire type for the field."""
@@ -235,37 +245,56 @@ class TypeInfo(ABC):
         "encode_bool": "buffer.write_raw_byte({value} ? 0x01 : 0x00);",
     }
 
+    # When max_value < 128, the varint is always 1 byte — use a direct byte write
+    RAW_ENCODE_SMALL_MAP: dict[str, str] = {
+        "encode_uint32": "buffer.write_raw_byte(static_cast<uint8_t>({value}));",
+        "encode_uint64": "buffer.write_raw_byte(static_cast<uint8_t>({value}));",
+    }
+
     def _encode_with_precomputed_tag(self, value_expr: str) -> str | None:
         """Try to emit a precomputed-tag encode for a forced field.
 
         Returns the raw encode string if the tag is a single byte and the
         encode_func has a known raw equivalent, or None otherwise.
+        When max_value < 128, uses direct byte write instead of varint encoding.
         """
         if not self.force:
             return None
         tag = self.calculate_tag()
         if tag >= 128:
             return None
-        raw_expr = self.RAW_ENCODE_MAP.get(self.encode_func)
+        max_val = self.max_value
+        raw_expr = None
+        if max_val is not None and max_val < 128:
+            raw_expr = self.RAW_ENCODE_SMALL_MAP.get(self.encode_func)
+        if raw_expr is None:
+            raw_expr = self.RAW_ENCODE_MAP.get(self.encode_func)
         if raw_expr is None:
             return None
         return f"buffer.write_raw_byte({tag});\n{raw_expr.format(value=value_expr)}"
 
     def _encode_bytes_with_precomputed_tag(
-        self, data_expr: str, len_expr: str
+        self, data_expr: str, len_expr: str, max_len: int | None = None
     ) -> str | None:
         """Try to emit a precomputed-tag encode for a forced bytes/string field.
 
         Returns the raw encode string if the tag is a single byte, or None.
+        When max_len < 128, uses direct byte write for the length varint.
         """
         if not self.force:
             return None
         tag = self.calculate_tag()
         if tag >= 128:
             return None
+        # When max_len < 128, length varint is always 1 byte
+        len_encode = (
+            f"buffer.write_raw_byte(static_cast<uint8_t>({len_expr}));"
+            if max_len is not None and max_len < 128
+            else f"buffer.encode_varint_raw({len_expr});"
+        )
         return (
             f"buffer.write_raw_byte({tag});\n"
-            f"buffer.encode_varint_raw({len_expr});\n"
+            f"{len_encode}\n"
             f"buffer.encode_raw({data_expr}, {len_expr});"
         )
 
@@ -346,6 +375,31 @@ class TypeInfo(ABC):
         value = value_expr or name
         return f"size += ProtoSize::{method}({field_id_size}, {value});"
 
+    def _get_single_byte_varint_size(
+        self,
+        name: str,
+        force: bool,
+        extra_expr: str | None = None,
+        zero_check: str | None = None,
+    ) -> str:
+        """Size calculation when the varint is guaranteed to be 1 byte.
+
+        Used when max_value < 128 or fixed_array_size < 128.
+        The fixed part is field_id_size + 1 (tag + 1-byte varint).
+
+        Args:
+            name: Expression to check for zero (non-force only)
+            force: Whether to skip the zero check
+            extra_expr: Additional variable expression to add (e.g., data length)
+            zero_check: Override expression for the zero check (e.g., "!x.empty()")
+        """
+        fixed = self.calculate_field_id_size() + 1
+        size_expr = f"{fixed} + {extra_expr}" if extra_expr else str(fixed)
+        if force:
+            return f"size += {size_expr};"
+        check = zero_check or name
+        return f"size += {check} ? {size_expr} : 0;"
+
     @abstractmethod
     def get_size_calculation(self, name: str, force: bool = False) -> str:
         """Calculate the size needed for encoding this field.
@@ -1020,8 +1074,14 @@ class PointerToStringBufferType(PointerToBufferTypeBase):
 
     @property
     def encode_content(self) -> str:
+        max_len = self.max_data_length
+        if max_len is not None and max_len < 128 and self.force:
+            tag = self.calculate_tag()
+            if tag < 128:
+                return f"buffer.write_short_string({tag}, this->{self.field_name});"
         if result := self._encode_bytes_with_precomputed_tag(
-            f"this->{self.field_name}.c_str()", f"this->{self.field_name}.size()"
+            f"this->{self.field_name}.c_str()",
+            f"this->{self.field_name}.size()",
         ):
             return result
         if self.force:
@@ -1046,7 +1106,16 @@ class PointerToStringBufferType(PointerToBufferTypeBase):
         return f'dump_field(out, ESPHOME_PSTR("{self.name}"), this->{self.field_name});'
 
     def get_size_calculation(self, name: str, force: bool = False) -> str:
-        return f"size += ProtoSize::calc_length({self.calculate_field_id_size()}, this->{self.field_name}.size());"
+        size_field = f"this->{self.field_name}.size()"
+        max_len = self.max_data_length
+        if max_len is not None and max_len < 128:
+            return self._get_single_byte_varint_size(
+                size_field,
+                force,
+                extra_expr=size_field,
+                zero_check=f"!this->{self.field_name}.empty()",
+            )
+        return self._get_simple_size_calculation(size_field, force, "length")
 
     def get_estimated_size(self) -> int:
         return self.calculate_field_id_size() + 8  # field ID + 8 bytes typical string
@@ -1191,8 +1260,9 @@ class FixedArrayBytesType(TypeInfo):
 
     @property
     def encode_content(self) -> str:
+        max_len = self.array_size if isinstance(self.array_size, int) else None
         if result := self._encode_bytes_with_precomputed_tag(
-            f"this->{self.field_name}", f"this->{self.field_name}_len"
+            f"this->{self.field_name}", f"this->{self.field_name}_len", max_len=max_len
         ):
             return result
         if self.force:
@@ -1212,13 +1282,14 @@ class FixedArrayBytesType(TypeInfo):
     def get_size_calculation(self, name: str, force: bool = False) -> str:
         # Use the actual length stored in the _len field
         length_field = f"this->{self.field_name}_len"
-        field_id_size = self.calculate_field_id_size()
 
-        if force:
-            # For repeated fields, always calculate size (no zero check)
-            return f"size += ProtoSize::calc_length_force({field_id_size}, {length_field});"
-        # For non-repeated fields, length already checks for zero
-        return f"size += ProtoSize::calc_length({field_id_size}, {length_field});"
+        # When array_size < 128, length varint is always 1 byte
+        if isinstance(self.array_size, int) and self.array_size < 128:
+            return self._get_single_byte_varint_size(
+                length_field, force, extra_expr=length_field
+            )
+
+        return self._get_simple_size_calculation(length_field, force, "length")
 
     def get_estimated_size(self) -> int:
         # Estimate based on typical BLE advertisement size
@@ -1245,6 +1316,9 @@ class UInt32Type(TypeInfo):
         return o
 
     def get_size_calculation(self, name: str, force: bool = False) -> str:
+        max_val = self.max_value
+        if max_val is not None and max_val < 128:
+            return self._get_single_byte_varint_size(name, force)
         return self._get_simple_size_calculation(name, force, "uint32")
 
     def get_estimated_size(self) -> int:
diff --git a/tests/unit_tests/core/test_entity_helpers.py b/tests/unit_tests/core/test_entity_helpers.py
index d6cbb8c6be..e79ff850f9 100644
--- a/tests/unit_tests/core/test_entity_helpers.py
+++ b/tests/unit_tests/core/test_entity_helpers.py
@@ -28,6 +28,7 @@ from esphome.core.entity_helpers import (
     get_base_entity_object_id,
     register_device_class,
     register_icon,
+    register_unit_of_measurement,
     setup_device_class,
     setup_entity,
     setup_unit_of_measurement,
@@ -925,6 +926,22 @@ def test_register_device_class_max_length() -> None:
     assert register_device_class("") == 0
 
 
+def test_register_unit_of_measurement_max_length() -> None:
+    """Test register_unit_of_measurement rejects units exceeding 63 characters."""
+    # 63 chars should succeed
+    max_uom = "a" * 63
+    idx = register_unit_of_measurement(max_uom)
+    assert idx > 0
+
+    # 64 chars should fail
+    too_long = "a" * 64
+    with pytest.raises(ValueError, match="Unit of measurement string too long"):
+        register_unit_of_measurement(too_long)
+
+    # Empty string returns 0
+    assert register_unit_of_measurement("") == 0
+
+
 @pytest.mark.asyncio
 async def test_setup_entity_with_entity_category(
     setup_test_environment: list[str],