From 305667b06dcdc254fdfb93a6ef3354bc4cf34a5d Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Sun, 20 Jul 2025 18:59:48 -1000
Subject: [PATCH 01/14] [api] Sync uses_password field_ifdef optimization from
 aioesphomeapi (#9756)

---
 esphome/components/api/api.proto          | 2 +-
 esphome/components/api/api_connection.cpp | 2 --
 esphome/components/api/api_pb2.cpp        | 4 ++++
 esphome/components/api/api_pb2.h          | 2 ++
 esphome/components/api/api_pb2_dump.cpp   | 2 ++
 5 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/esphome/components/api/api.proto b/esphome/components/api/api.proto
index 546c498ff3..fd08e87bbf 100644
--- a/esphome/components/api/api.proto
+++ b/esphome/components/api/api.proto
@@ -203,7 +203,7 @@ message DeviceInfoResponse {
   option (id) = 10;
   option (source) = SOURCE_SERVER;
 
-  bool uses_password = 1;
+  bool uses_password = 1 [(field_ifdef) = "USE_API_PASSWORD"];
 
   // The name of the node, given by "App.set_name()"
   string name = 2;
diff --git a/esphome/components/api/api_connection.cpp b/esphome/components/api/api_connection.cpp
index 602a0256cf..bc0afd49eb 100644
--- a/esphome/components/api/api_connection.cpp
+++ b/esphome/components/api/api_connection.cpp
@@ -1432,8 +1432,6 @@ DeviceInfoResponse APIConnection::device_info(const DeviceInfoRequest &msg) {
   DeviceInfoResponse resp{};
 #ifdef USE_API_PASSWORD
   resp.uses_password = true;
-#else
-  resp.uses_password = false;
 #endif
   resp.name = App.get_name();
   resp.friendly_name = App.get_friendly_name();
diff --git a/esphome/components/api/api_pb2.cpp b/esphome/components/api/api_pb2.cpp
index 4cf4b63269..528c581ad7 100644
--- a/esphome/components/api/api_pb2.cpp
+++ b/esphome/components/api/api_pb2.cpp
@@ -80,7 +80,9 @@ void DeviceInfo::calculate_size(uint32_t &total_size) const {
 }
 #endif
 void DeviceInfoResponse::encode(ProtoWriteBuffer buffer) const {
+#ifdef USE_API_PASSWORD
   buffer.encode_bool(1, this->uses_password);
+#endif
   buffer.encode_string(2, this->name);
   buffer.encode_string(3, this->mac_address);
   buffer.encode_string(4, this->esphome_version);
@@ -130,7 +132,9 @@ void DeviceInfoResponse::encode(ProtoWriteBuffer buffer) const {
 #endif
 }
 void DeviceInfoResponse::calculate_size(uint32_t &total_size) const {
+#ifdef USE_API_PASSWORD
   ProtoSize::add_bool_field(total_size, 1, this->uses_password);
+#endif
   ProtoSize::add_string_field(total_size, 1, this->name);
   ProtoSize::add_string_field(total_size, 1, this->mac_address);
   ProtoSize::add_string_field(total_size, 1, this->esphome_version);
diff --git a/esphome/components/api/api_pb2.h b/esphome/components/api/api_pb2.h
index e241451ec8..7b64bd889f 100644
--- a/esphome/components/api/api_pb2.h
+++ b/esphome/components/api/api_pb2.h
@@ -474,7 +474,9 @@ class DeviceInfoResponse : public ProtoMessage {
 #ifdef HAS_PROTO_MESSAGE_DUMP
   const char *message_name() const override { return "device_info_response"; }
 #endif
+#ifdef USE_API_PASSWORD
   bool uses_password{false};
+#endif
   std::string name{};
   std::string mac_address{};
   std::string esphome_version{};
diff --git a/esphome/components/api/api_pb2_dump.cpp b/esphome/components/api/api_pb2_dump.cpp
index bda5ec5764..4951c6cebf 100644
--- a/esphome/components/api/api_pb2_dump.cpp
+++ b/esphome/components/api/api_pb2_dump.cpp
@@ -647,10 +647,12 @@ void DeviceInfo::dump_to(std::string &out) const {
 void DeviceInfoResponse::dump_to(std::string &out) const {
   __attribute__((unused)) char buffer[64];
   out.append("DeviceInfoResponse {\n");
+#ifdef USE_API_PASSWORD
   out.append("  uses_password: ");
   out.append(YESNO(this->uses_password));
   out.append("\n");
 
+#endif
   out.append("  name: ");
   out.append("'").append(this->name).append("'");
   out.append("\n");

From 54bbde61832731ffbfa40a6f4b303dee80ed2dc2 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Sun, 20 Jul 2025 19:01:41 -1000
Subject: [PATCH 02/14] zero copy cleanup

---
 esphome/components/api/api.proto          |  4 +--
 esphome/components/api/api_connection.cpp | 43 ++++++-----------------
 esphome/components/api/api_options.proto  |  1 +
 esphome/components/api/api_pb2.cpp        |  8 ++---
 esphome/components/api/api_pb2.h          | 14 ++++++--
 esphome/components/api/api_pb2_dump.cpp   |  4 +--
 esphome/components/api/proto.h            | 32 +++++++----------
 script/api_protobuf/api_protobuf.py       | 43 +++++++++++++++++++++++
 8 files changed, 87 insertions(+), 62 deletions(-)

diff --git a/esphome/components/api/api.proto b/esphome/components/api/api.proto
index 546c498ff3..4dec686c68 100644
--- a/esphome/components/api/api.proto
+++ b/esphome/components/api/api.proto
@@ -731,7 +731,7 @@ message SubscribeLogsResponse {
   option (no_delay) = false;
 
   LogLevel level = 1;
-  bytes message = 3;
+  bytes message = 3 [(zero_copy) = true];
   bool send_failed = 4;
 }
 
@@ -888,7 +888,7 @@ message CameraImageResponse {
   option (ifdef) = "USE_CAMERA";
 
   fixed32 key = 1;
-  bytes data = 2;
+  bytes data = 2 [(zero_copy) = true];
   bool done = 3;
   uint32 device_id = 4 [(field_ifdef) = "USE_DEVICES"];
 }
diff --git a/esphome/components/api/api_connection.cpp b/esphome/components/api/api_connection.cpp
index 602a0256cf..2fd3d4e1ea 100644
--- a/esphome/components/api/api_connection.cpp
+++ b/esphome/components/api/api_connection.cpp
@@ -225,22 +225,13 @@ void APIConnection::loop() {
   if (this->image_reader_ && this->image_reader_->available() && this->helper_->can_write_without_blocking()) {
     uint32_t to_send = std::min((size_t) MAX_BATCH_PACKET_SIZE, this->image_reader_->available());
     bool done = this->image_reader_->available() == to_send;
-    uint32_t msg_size = 0;
-    ProtoSize::add_fixed_field<4>(msg_size, 1, true);
-    // partial message size calculated manually since its a special case
-    // 1 for the data field, varint for the data size, and the data itself
-    msg_size += 1 + ProtoSize::varint(to_send) + to_send;
-    ProtoSize::add_bool_field(msg_size, 1, done);
 
-    auto buffer = this->create_buffer(msg_size);
-    // fixed32 key = 1;
-    buffer.encode_fixed32(1, camera::Camera::instance()->get_object_id_hash());
-    // bytes data = 2;
-    buffer.encode_bytes(2, this->image_reader_->peek_data_buffer(), to_send);
-    // bool done = 3;
-    buffer.encode_bool(3, done);
+    CameraImageResponse msg;
+    msg.key = camera::Camera::instance()->get_object_id_hash();
+    msg.set_data(this->image_reader_->peek_data_buffer(), to_send);
+    msg.done = done;
 
-    bool success = this->send_buffer(buffer, CameraImageResponse::MESSAGE_TYPE);
+    bool success = this->send_message_(msg, CameraImageResponse::MESSAGE_TYPE);
 
     if (success) {
       this->image_reader_->consume_data(to_send);
@@ -1350,26 +1341,12 @@ void APIConnection::update_command(const UpdateCommandRequest &msg) {
 #endif
 
 bool APIConnection::try_send_log_message(int level, const char *tag, const char *line, size_t message_len) {
-  // Pre-calculate message size to avoid reallocations
-  uint32_t msg_size = 0;
+  SubscribeLogsResponse msg;
+  msg.level = static_cast<enums::LogLevel>(level);
+  msg.set_message(reinterpret_cast<const uint8_t *>(line), message_len);
+  msg.send_failed = false;
 
-  // Add size for level field (field ID 1, varint type)
-  // 1 byte for field tag + size of the level varint
-  msg_size += 1 + api::ProtoSize::varint(static_cast<uint32_t>(level));
-
-  // Add size for string field (field ID 3, string type)
-  // 1 byte for field tag + size of length varint + string length
-  msg_size += 1 + api::ProtoSize::varint(static_cast<uint32_t>(message_len)) + message_len;
-
-  // Create a pre-sized buffer
-  auto buffer = this->create_buffer(msg_size);
-
-  // Encode the message (SubscribeLogsResponse)
-  buffer.encode_uint32(1, static_cast<uint32_t>(level));  // LogLevel level = 1
-  buffer.encode_string(3, line, message_len);             // string message = 3
-
-  // SubscribeLogsResponse - 29
-  return this->send_buffer(buffer, SubscribeLogsResponse::MESSAGE_TYPE);
+  return this->send_message_(msg, SubscribeLogsResponse::MESSAGE_TYPE);
 }
 
 void APIConnection::complete_authentication_() {
diff --git a/esphome/components/api/api_options.proto b/esphome/components/api/api_options.proto
index bb3947e8a3..d5e3df6593 100644
--- a/esphome/components/api/api_options.proto
+++ b/esphome/components/api/api_options.proto
@@ -27,4 +27,5 @@ extend google.protobuf.MessageOptions {
 extend google.protobuf.FieldOptions {
     optional string field_ifdef = 1042;
     optional uint32 fixed_array_size = 50007;
+    optional bool zero_copy = 1043 [default=false];
 }
diff --git a/esphome/components/api/api_pb2.cpp b/esphome/components/api/api_pb2.cpp
index 4cf4b63269..25156abf03 100644
--- a/esphome/components/api/api_pb2.cpp
+++ b/esphome/components/api/api_pb2.cpp
@@ -818,12 +818,12 @@ bool SubscribeLogsRequest::decode_varint(uint32_t field_id, ProtoVarInt value) {
 }
 void SubscribeLogsResponse::encode(ProtoWriteBuffer buffer) const {
   buffer.encode_uint32(1, static_cast<uint32_t>(this->level));
-  buffer.encode_bytes(3, reinterpret_cast<const uint8_t *>(this->message.data()), this->message.size());
+  buffer.encode_bytes(3, this->message_ptr_, this->message_len_);
   buffer.encode_bool(4, this->send_failed);
 }
 void SubscribeLogsResponse::calculate_size(uint32_t &total_size) const {
   ProtoSize::add_enum_field(total_size, 1, static_cast<uint32_t>(this->level));
-  ProtoSize::add_string_field(total_size, 1, this->message);
+  ProtoSize::add_bytes_field(total_size, 1, this->message_len_);
   ProtoSize::add_bool_field(total_size, 1, this->send_failed);
 }
 #ifdef USE_API_NOISE
@@ -1030,7 +1030,7 @@ void ListEntitiesCameraResponse::calculate_size(uint32_t &total_size) const {
 }
 void CameraImageResponse::encode(ProtoWriteBuffer buffer) const {
   buffer.encode_fixed32(1, this->key);
-  buffer.encode_bytes(2, reinterpret_cast<const uint8_t *>(this->data.data()), this->data.size());
+  buffer.encode_bytes(2, this->data_ptr_, this->data_len_);
   buffer.encode_bool(3, this->done);
 #ifdef USE_DEVICES
   buffer.encode_uint32(4, this->device_id);
@@ -1038,7 +1038,7 @@ void CameraImageResponse::encode(ProtoWriteBuffer buffer) const {
 }
 void CameraImageResponse::calculate_size(uint32_t &total_size) const {
   ProtoSize::add_fixed32_field(total_size, 1, this->key);
-  ProtoSize::add_string_field(total_size, 1, this->data);
+  ProtoSize::add_bytes_field(total_size, 1, this->data_len_);
   ProtoSize::add_bool_field(total_size, 1, this->done);
 #ifdef USE_DEVICES
   ProtoSize::add_uint32_field(total_size, 1, this->device_id);
diff --git a/esphome/components/api/api_pb2.h b/esphome/components/api/api_pb2.h
index e241451ec8..7512431ccf 100644
--- a/esphome/components/api/api_pb2.h
+++ b/esphome/components/api/api_pb2.h
@@ -968,7 +968,12 @@ class SubscribeLogsResponse : public ProtoMessage {
   const char *message_name() const override { return "subscribe_logs_response"; }
 #endif
   enums::LogLevel level{};
-  std::string message{};
+  const uint8_t *message_ptr_{nullptr};
+  size_t message_len_{0};
+  void set_message(const uint8_t *data, size_t len) {
+    this->message_ptr_ = data;
+    this->message_len_ = len;
+  }
   bool send_failed{false};
   void encode(ProtoWriteBuffer buffer) const override;
   void calculate_size(uint32_t &total_size) const override;
@@ -1226,7 +1231,12 @@ class CameraImageResponse : public StateResponseProtoMessage {
 #ifdef HAS_PROTO_MESSAGE_DUMP
   const char *message_name() const override { return "camera_image_response"; }
 #endif
-  std::string data{};
+  const uint8_t *data_ptr_{nullptr};
+  size_t data_len_{0};
+  void set_data(const uint8_t *data, size_t len) {
+    this->data_ptr_ = data;
+    this->data_len_ = len;
+  }
   bool done{false};
   void encode(ProtoWriteBuffer buffer) const override;
   void calculate_size(uint32_t &total_size) const override;
diff --git a/esphome/components/api/api_pb2_dump.cpp b/esphome/components/api/api_pb2_dump.cpp
index bda5ec5764..59d9aff209 100644
--- a/esphome/components/api/api_pb2_dump.cpp
+++ b/esphome/components/api/api_pb2_dump.cpp
@@ -1666,7 +1666,7 @@ void SubscribeLogsResponse::dump_to(std::string &out) const {
   out.append("\n");
 
   out.append("  message: ");
-  out.append(format_hex_pretty(this->message));
+  out.append(format_hex_pretty(this->message_ptr_, this->message_len_));
   out.append("\n");
 
   out.append("  send_failed: ");
@@ -1932,7 +1932,7 @@ void CameraImageResponse::dump_to(std::string &out) const {
   out.append("\n");
 
   out.append("  data: ");
-  out.append(format_hex_pretty(this->data));
+  out.append(format_hex_pretty(this->data_ptr_, this->data_len_));
   out.append("\n");
 
   out.append("  done: ");
diff --git a/esphome/components/api/proto.h b/esphome/components/api/proto.h
index a2c31100bf..0ba8df84da 100644
--- a/esphome/components/api/proto.h
+++ b/esphome/components/api/proto.h
@@ -527,25 +527,6 @@ class ProtoSize {
     total_size += field_id_size + 1;
   }
 
-  /**
-   * @brief Calculates and adds the size of a fixed field to the total message size
-   *
-   * Fixed fields always take exactly N bytes (4 for fixed32/float, 8 for fixed64/double).
-   *
-   * @tparam NumBytes The number of bytes for this fixed field (4 or 8)
-   * @param is_nonzero Whether the value is non-zero
-   */
-  template<uint32_t NumBytes>
-  static inline void add_fixed_field(uint32_t &total_size, uint32_t field_id_size, bool is_nonzero) {
-    // Skip calculation if value is zero
-    if (!is_nonzero) {
-      return;  // No need to update total_size
-    }
-
-    // Fixed fields always take exactly NumBytes
-    total_size += field_id_size + NumBytes;
-  }
-
   /**
    * @brief Calculates and adds the size of a float field to the total message size
    */
@@ -704,6 +685,19 @@ class ProtoSize {
     total_size += field_id_size + varint(str_size) + str_size;
   }
 
+  /**
+   * @brief Calculates and adds the size of a bytes field to the total message size
+   */
+  static inline void add_bytes_field(uint32_t &total_size, uint32_t field_id_size, size_t len) {
+    // Skip calculation if bytes is empty
+    if (len == 0) {
+      return;  // No need to update total_size
+    }
+
+    // Field ID + length varint + data bytes
+    total_size += field_id_size + varint(static_cast<uint32_t>(len)) + static_cast<uint32_t>(len);
+  }
+
   /**
    * @brief Calculates and adds the size of a nested message field to the total message size
    *
diff --git a/script/api_protobuf/api_protobuf.py b/script/api_protobuf/api_protobuf.py
index ad6c3c3ed2..5569f29818 100755
--- a/script/api_protobuf/api_protobuf.py
+++ b/script/api_protobuf/api_protobuf.py
@@ -325,6 +325,10 @@ def create_field_type_info(field: descriptor.FieldDescriptorProto) -> TypeInfo:
     ):
         return FixedArrayBytesType(field, fixed_size)
 
+    # Check for zero_copy option on bytes fields
+    if field.type == 12 and get_field_opt(field, pb.zero_copy, default=False):
+        return ZeroCopyBytesType(field)
+
     validate_field_type(field.type, field.name)
     return TYPE_INFO[field.type](field)
 
@@ -608,6 +612,45 @@ class BytesType(TypeInfo):
         return self.calculate_field_id_size() + 8  # field ID + 8 bytes typical bytes
 
 
+class ZeroCopyBytesType(TypeInfo):
+    """Special type for zero-copy bytes fields that only accepts const uint8_t* data."""
+
+    cpp_type = "std::string"  # Still store as string for compatibility
+    default_value = ""
+    reference_type = "std::string &"
+    const_reference_type = "const std::string &"
+    encode_func = "encode_bytes"
+    wire_type = WireType.LENGTH_DELIMITED
+    decode_length = "value.as_string()"
+
+    @property
+    def public_content(self) -> list[str]:
+        # Store both pointer and length for zero-copy encoding, plus setter method
+        return [
+            f"const uint8_t* {self.field_name}_ptr_{{nullptr}};",
+            f"size_t {self.field_name}_len_{{0}};",
+            f"void set_{self.field_name}(const uint8_t* data, size_t len) {{",
+            f"  this->{self.field_name}_ptr_ = data;",
+            f"  this->{self.field_name}_len_ = len;",
+            "}",
+        ]
+
+    @property
+    def encode_content(self) -> str:
+        # Encode directly from pointer without nullptr check (like original)
+        return f"buffer.encode_bytes({self.number}, this->{self.field_name}_ptr_, this->{self.field_name}_len_);"
+
+    def dump(self, name: str) -> str:
+        return f"out.append(format_hex_pretty(this->{self.field_name}_ptr_, this->{self.field_name}_len_));"
+
+    def get_size_calculation(self, name: str, force: bool = False) -> str:
+        # Use the new add_bytes_field helper
+        return f"ProtoSize::add_bytes_field(total_size, {self.calculate_field_id_size()}, this->{self.field_name}_len_);"
+
+    def get_estimated_size(self) -> int:
+        return self.calculate_field_id_size() + 8  # field ID + 8 bytes typical bytes
+
+
 class FixedArrayBytesType(TypeInfo):
     """Special type for fixed-size byte arrays."""
 

From 7de63d06708104bb6b7673fb7063dae741e8addd Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Sun, 20 Jul 2025 19:18:25 -1000
Subject: [PATCH 03/14] fixes

---
 esphome/components/api/api.proto              |  4 +-
 esphome/components/api/api_connection.cpp     |  4 +-
 esphome/components/api/api_options.proto      |  1 -
 esphome/components/api/api_pb2.cpp            | 12 +++---
 esphome/components/api/api_pb2.h              | 42 ++++++++++++++++---
 esphome/components/api/api_pb2_dump.cpp       | 12 +++---
 .../bluetooth_proxy/bluetooth_connection.cpp  | 17 ++++----
 .../bluetooth_proxy/bluetooth_connection.h    |  4 +-
 .../bluetooth_proxy/bluetooth_proxy.cpp       |  4 +-
 .../voice_assistant/voice_assistant.cpp       | 14 +++----
 script/api_protobuf/api_protobuf.py           | 32 --------------
 11 files changed, 71 insertions(+), 75 deletions(-)

diff --git a/esphome/components/api/api.proto b/esphome/components/api/api.proto
index 4dec686c68..546c498ff3 100644
--- a/esphome/components/api/api.proto
+++ b/esphome/components/api/api.proto
@@ -731,7 +731,7 @@ message SubscribeLogsResponse {
   option (no_delay) = false;
 
   LogLevel level = 1;
-  bytes message = 3 [(zero_copy) = true];
+  bytes message = 3;
   bool send_failed = 4;
 }
 
@@ -888,7 +888,7 @@ message CameraImageResponse {
   option (ifdef) = "USE_CAMERA";
 
   fixed32 key = 1;
-  bytes data = 2 [(zero_copy) = true];
+  bytes data = 2;
   bool done = 3;
   uint32 device_id = 4 [(field_ifdef) = "USE_DEVICES"];
 }
diff --git a/esphome/components/api/api_connection.cpp b/esphome/components/api/api_connection.cpp
index 2fd3d4e1ea..c3cee7d80d 100644
--- a/esphome/components/api/api_connection.cpp
+++ b/esphome/components/api/api_connection.cpp
@@ -1497,7 +1497,9 @@ void APIConnection::execute_service(const ExecuteServiceRequest &msg) {
 NoiseEncryptionSetKeyResponse APIConnection::noise_encryption_set_key(const NoiseEncryptionSetKeyRequest &msg) {
   psk_t psk{};
   NoiseEncryptionSetKeyResponse resp;
-  if (base64_decode(msg.key, psk.data(), msg.key.size()) != psk.size()) {
+  // Create temporary string from pointer/length for base64_decode
+  std::string key_str(reinterpret_cast<const char *>(msg.key_ptr_), msg.key_len_);
+  if (base64_decode(key_str, psk.data(), key_str.size()) != psk.size()) {
     ESP_LOGW(TAG, "Invalid encryption key length");
     resp.success = false;
     return resp;
diff --git a/esphome/components/api/api_options.proto b/esphome/components/api/api_options.proto
index d5e3df6593..bb3947e8a3 100644
--- a/esphome/components/api/api_options.proto
+++ b/esphome/components/api/api_options.proto
@@ -27,5 +27,4 @@ extend google.protobuf.MessageOptions {
 extend google.protobuf.FieldOptions {
     optional string field_ifdef = 1042;
     optional uint32 fixed_array_size = 50007;
-    optional bool zero_copy = 1043 [default=false];
 }
diff --git a/esphome/components/api/api_pb2.cpp b/esphome/components/api/api_pb2.cpp
index 25156abf03..3b1f8d201f 100644
--- a/esphome/components/api/api_pb2.cpp
+++ b/esphome/components/api/api_pb2.cpp
@@ -1972,12 +1972,12 @@ bool BluetoothGATTReadRequest::decode_varint(uint32_t field_id, ProtoVarInt valu
 void BluetoothGATTReadResponse::encode(ProtoWriteBuffer buffer) const {
   buffer.encode_uint64(1, this->address);
   buffer.encode_uint32(2, this->handle);
-  buffer.encode_bytes(3, reinterpret_cast<const uint8_t *>(this->data.data()), this->data.size());
+  buffer.encode_bytes(3, this->data_ptr_, this->data_len_);
 }
 void BluetoothGATTReadResponse::calculate_size(uint32_t &total_size) const {
   ProtoSize::add_uint64_field(total_size, 1, this->address);
   ProtoSize::add_uint32_field(total_size, 1, this->handle);
-  ProtoSize::add_string_field(total_size, 1, this->data);
+  ProtoSize::add_bytes_field(total_size, 1, this->data_len_);
 }
 bool BluetoothGATTWriteRequest::decode_varint(uint32_t field_id, ProtoVarInt value) {
   switch (field_id) {
@@ -2060,12 +2060,12 @@ bool BluetoothGATTNotifyRequest::decode_varint(uint32_t field_id, ProtoVarInt va
 void BluetoothGATTNotifyDataResponse::encode(ProtoWriteBuffer buffer) const {
   buffer.encode_uint64(1, this->address);
   buffer.encode_uint32(2, this->handle);
-  buffer.encode_bytes(3, reinterpret_cast<const uint8_t *>(this->data.data()), this->data.size());
+  buffer.encode_bytes(3, this->data_ptr_, this->data_len_);
 }
 void BluetoothGATTNotifyDataResponse::calculate_size(uint32_t &total_size) const {
   ProtoSize::add_uint64_field(total_size, 1, this->address);
   ProtoSize::add_uint32_field(total_size, 1, this->handle);
-  ProtoSize::add_string_field(total_size, 1, this->data);
+  ProtoSize::add_bytes_field(total_size, 1, this->data_len_);
 }
 void BluetoothConnectionsFreeResponse::encode(ProtoWriteBuffer buffer) const {
   buffer.encode_uint32(1, this->free);
@@ -2264,11 +2264,11 @@ bool VoiceAssistantAudio::decode_length(uint32_t field_id, ProtoLengthDelimited
   return true;
 }
 void VoiceAssistantAudio::encode(ProtoWriteBuffer buffer) const {
-  buffer.encode_bytes(1, reinterpret_cast<const uint8_t *>(this->data.data()), this->data.size());
+  buffer.encode_bytes(1, this->data_ptr_, this->data_len_);
   buffer.encode_bool(2, this->end);
 }
 void VoiceAssistantAudio::calculate_size(uint32_t &total_size) const {
-  ProtoSize::add_string_field(total_size, 1, this->data);
+  ProtoSize::add_bytes_field(total_size, 1, this->data_len_);
   ProtoSize::add_bool_field(total_size, 1, this->end);
 }
 bool VoiceAssistantTimerEventResponse::decode_varint(uint32_t field_id, ProtoVarInt value) {
diff --git a/esphome/components/api/api_pb2.h b/esphome/components/api/api_pb2.h
index 7512431ccf..f116cfe4f9 100644
--- a/esphome/components/api/api_pb2.h
+++ b/esphome/components/api/api_pb2.h
@@ -991,7 +991,12 @@ class NoiseEncryptionSetKeyRequest : public ProtoDecodableMessage {
 #ifdef HAS_PROTO_MESSAGE_DUMP
   const char *message_name() const override { return "noise_encryption_set_key_request"; }
 #endif
-  std::string key{};
+  const uint8_t *key_ptr_{nullptr};
+  size_t key_len_{0};
+  void set_key(const uint8_t *data, size_t len) {
+    this->key_ptr_ = data;
+    this->key_len_ = len;
+  }
 #ifdef HAS_PROTO_MESSAGE_DUMP
   void dump_to(std::string &out) const override;
 #endif
@@ -1890,7 +1895,12 @@ class BluetoothGATTReadResponse : public ProtoMessage {
 #endif
   uint64_t address{0};
   uint32_t handle{0};
-  std::string data{};
+  const uint8_t *data_ptr_{nullptr};
+  size_t data_len_{0};
+  void set_data(const uint8_t *data, size_t len) {
+    this->data_ptr_ = data;
+    this->data_len_ = len;
+  }
   void encode(ProtoWriteBuffer buffer) const override;
   void calculate_size(uint32_t &total_size) const override;
 #ifdef HAS_PROTO_MESSAGE_DUMP
@@ -1909,7 +1919,12 @@ class BluetoothGATTWriteRequest : public ProtoDecodableMessage {
   uint64_t address{0};
   uint32_t handle{0};
   bool response{false};
-  std::string data{};
+  const uint8_t *data_ptr_{nullptr};
+  size_t data_len_{0};
+  void set_data(const uint8_t *data, size_t len) {
+    this->data_ptr_ = data;
+    this->data_len_ = len;
+  }
 #ifdef HAS_PROTO_MESSAGE_DUMP
   void dump_to(std::string &out) const override;
 #endif
@@ -1943,7 +1958,12 @@ class BluetoothGATTWriteDescriptorRequest : public ProtoDecodableMessage {
 #endif
   uint64_t address{0};
   uint32_t handle{0};
-  std::string data{};
+  const uint8_t *data_ptr_{nullptr};
+  size_t data_len_{0};
+  void set_data(const uint8_t *data, size_t len) {
+    this->data_ptr_ = data;
+    this->data_len_ = len;
+  }
 #ifdef HAS_PROTO_MESSAGE_DUMP
   void dump_to(std::string &out) const override;
 #endif
@@ -1978,7 +1998,12 @@ class BluetoothGATTNotifyDataResponse : public ProtoMessage {
 #endif
   uint64_t address{0};
   uint32_t handle{0};
-  std::string data{};
+  const uint8_t *data_ptr_{nullptr};
+  size_t data_len_{0};
+  void set_data(const uint8_t *data, size_t len) {
+    this->data_ptr_ = data;
+    this->data_len_ = len;
+  }
   void encode(ProtoWriteBuffer buffer) const override;
   void calculate_size(uint32_t &total_size) const override;
 #ifdef HAS_PROTO_MESSAGE_DUMP
@@ -2271,7 +2296,12 @@ class VoiceAssistantAudio : public ProtoDecodableMessage {
 #ifdef HAS_PROTO_MESSAGE_DUMP
   const char *message_name() const override { return "voice_assistant_audio"; }
 #endif
-  std::string data{};
+  const uint8_t *data_ptr_{nullptr};
+  size_t data_len_{0};
+  void set_data(const uint8_t *data, size_t len) {
+    this->data_ptr_ = data;
+    this->data_len_ = len;
+  }
   bool end{false};
   void encode(ProtoWriteBuffer buffer) const override;
   void calculate_size(uint32_t &total_size) const override;
diff --git a/esphome/components/api/api_pb2_dump.cpp b/esphome/components/api/api_pb2_dump.cpp
index 59d9aff209..7eb0da6a6f 100644
--- a/esphome/components/api/api_pb2_dump.cpp
+++ b/esphome/components/api/api_pb2_dump.cpp
@@ -1679,7 +1679,7 @@ void NoiseEncryptionSetKeyRequest::dump_to(std::string &out) const {
   __attribute__((unused)) char buffer[64];
   out.append("NoiseEncryptionSetKeyRequest {\n");
   out.append("  key: ");
-  out.append(format_hex_pretty(this->key));
+  out.append(format_hex_pretty(this->key_ptr_, this->key_len_));
   out.append("\n");
   out.append("}");
 }
@@ -3141,7 +3141,7 @@ void BluetoothGATTReadResponse::dump_to(std::string &out) const {
   out.append("\n");
 
   out.append("  data: ");
-  out.append(format_hex_pretty(this->data));
+  out.append(format_hex_pretty(this->data_ptr_, this->data_len_));
   out.append("\n");
   out.append("}");
 }
@@ -3163,7 +3163,7 @@ void BluetoothGATTWriteRequest::dump_to(std::string &out) const {
   out.append("\n");
 
   out.append("  data: ");
-  out.append(format_hex_pretty(this->data));
+  out.append(format_hex_pretty(this->data_ptr_, this->data_len_));
   out.append("\n");
   out.append("}");
 }
@@ -3195,7 +3195,7 @@ void BluetoothGATTWriteDescriptorRequest::dump_to(std::string &out) const {
   out.append("\n");
 
   out.append("  data: ");
-  out.append(format_hex_pretty(this->data));
+  out.append(format_hex_pretty(this->data_ptr_, this->data_len_));
   out.append("\n");
   out.append("}");
 }
@@ -3231,7 +3231,7 @@ void BluetoothGATTNotifyDataResponse::dump_to(std::string &out) const {
   out.append("\n");
 
   out.append("  data: ");
-  out.append(format_hex_pretty(this->data));
+  out.append(format_hex_pretty(this->data_ptr_, this->data_len_));
   out.append("\n");
   out.append("}");
 }
@@ -3485,7 +3485,7 @@ void VoiceAssistantAudio::dump_to(std::string &out) const {
   __attribute__((unused)) char buffer[64];
   out.append("VoiceAssistantAudio {\n");
   out.append("  data: ");
-  out.append(format_hex_pretty(this->data));
+  out.append(format_hex_pretty(this->data_ptr_, this->data_len_));
   out.append("\n");
 
   out.append("  end: ");
diff --git a/esphome/components/bluetooth_proxy/bluetooth_connection.cpp b/esphome/components/bluetooth_proxy/bluetooth_connection.cpp
index dae6e521bb..8e08d62504 100644
--- a/esphome/components/bluetooth_proxy/bluetooth_connection.cpp
+++ b/esphome/components/bluetooth_proxy/bluetooth_connection.cpp
@@ -235,9 +235,7 @@ bool BluetoothConnection::gattc_event_handler(esp_gattc_cb_event_t event, esp_ga
       api::BluetoothGATTReadResponse resp;
       resp.address = this->address_;
       resp.handle = param->read.handle;
-      resp.data.reserve(param->read.value_len);
-      // Use bulk insert instead of individual push_backs
-      resp.data.insert(resp.data.end(), param->read.value, param->read.value + param->read.value_len);
+      resp.set_data(param->read.value, param->read.value_len);
       this->proxy_->get_api_connection()->send_message(resp, api::BluetoothGATTReadResponse::MESSAGE_TYPE);
       break;
     }
@@ -288,9 +286,7 @@ bool BluetoothConnection::gattc_event_handler(esp_gattc_cb_event_t event, esp_ga
       api::BluetoothGATTNotifyDataResponse resp;
       resp.address = this->address_;
       resp.handle = param->notify.handle;
-      resp.data.reserve(param->notify.value_len);
-      // Use bulk insert instead of individual push_backs
-      resp.data.insert(resp.data.end(), param->notify.value, param->notify.value + param->notify.value_len);
+      resp.set_data(param->notify.value, param->notify.value_len);
       this->proxy_->get_api_connection()->send_message(resp, api::BluetoothGATTNotifyDataResponse::MESSAGE_TYPE);
       break;
     }
@@ -337,7 +333,8 @@ esp_err_t BluetoothConnection::read_characteristic(uint16_t handle) {
   return ESP_OK;
 }
 
-esp_err_t BluetoothConnection::write_characteristic(uint16_t handle, const std::string &data, bool response) {
+esp_err_t BluetoothConnection::write_characteristic(uint16_t handle, const uint8_t *data, size_t data_len,
+                                                    bool response) {
   if (!this->connected()) {
     ESP_LOGW(TAG, "[%d] [%s] Cannot write GATT characteristic, not connected.", this->connection_index_,
              this->address_str_.c_str());
@@ -347,7 +344,7 @@ esp_err_t BluetoothConnection::write_characteristic(uint16_t handle, const std::
            handle);
 
   esp_err_t err =
-      esp_ble_gattc_write_char(this->gattc_if_, this->conn_id_, handle, data.size(), (uint8_t *) data.data(),
+      esp_ble_gattc_write_char(this->gattc_if_, this->conn_id_, handle, data_len, const_cast<uint8_t *>(data),
                                response ? ESP_GATT_WRITE_TYPE_RSP : ESP_GATT_WRITE_TYPE_NO_RSP, ESP_GATT_AUTH_REQ_NONE);
   if (err != ERR_OK) {
     ESP_LOGW(TAG, "[%d] [%s] esp_ble_gattc_write_char error, err=%d", this->connection_index_,
@@ -375,7 +372,7 @@ esp_err_t BluetoothConnection::read_descriptor(uint16_t handle) {
   return ESP_OK;
 }
 
-esp_err_t BluetoothConnection::write_descriptor(uint16_t handle, const std::string &data, bool response) {
+esp_err_t BluetoothConnection::write_descriptor(uint16_t handle, const uint8_t *data, size_t data_len, bool response) {
   if (!this->connected()) {
     ESP_LOGW(TAG, "[%d] [%s] Cannot write GATT descriptor, not connected.", this->connection_index_,
              this->address_str_.c_str());
@@ -385,7 +382,7 @@ esp_err_t BluetoothConnection::write_descriptor(uint16_t handle, const std::stri
            handle);
 
   esp_err_t err = esp_ble_gattc_write_char_descr(
-      this->gattc_if_, this->conn_id_, handle, data.size(), (uint8_t *) data.data(),
+      this->gattc_if_, this->conn_id_, handle, data_len, const_cast<uint8_t *>(data),
       response ? ESP_GATT_WRITE_TYPE_RSP : ESP_GATT_WRITE_TYPE_NO_RSP, ESP_GATT_AUTH_REQ_NONE);
   if (err != ERR_OK) {
     ESP_LOGW(TAG, "[%d] [%s] esp_ble_gattc_write_char_descr error, err=%d", this->connection_index_,
diff --git a/esphome/components/bluetooth_proxy/bluetooth_connection.h b/esphome/components/bluetooth_proxy/bluetooth_connection.h
index 2673238fba..c9c4b7c901 100644
--- a/esphome/components/bluetooth_proxy/bluetooth_connection.h
+++ b/esphome/components/bluetooth_proxy/bluetooth_connection.h
@@ -19,9 +19,9 @@ class BluetoothConnection : public esp32_ble_client::BLEClientBase {
   esp32_ble_tracker::AdvertisementParserType get_advertisement_parser_type() override;
 
   esp_err_t read_characteristic(uint16_t handle);
-  esp_err_t write_characteristic(uint16_t handle, const std::string &data, bool response);
+  esp_err_t write_characteristic(uint16_t handle, const uint8_t *data, size_t data_len, bool response);
   esp_err_t read_descriptor(uint16_t handle);
-  esp_err_t write_descriptor(uint16_t handle, const std::string &data, bool response);
+  esp_err_t write_descriptor(uint16_t handle, const uint8_t *data, size_t data_len, bool response);
 
   esp_err_t notify_characteristic(uint16_t handle, bool enable);
 
diff --git a/esphome/components/bluetooth_proxy/bluetooth_proxy.cpp b/esphome/components/bluetooth_proxy/bluetooth_proxy.cpp
index 8a1a2bff6a..66423d201d 100644
--- a/esphome/components/bluetooth_proxy/bluetooth_proxy.cpp
+++ b/esphome/components/bluetooth_proxy/bluetooth_proxy.cpp
@@ -344,7 +344,7 @@ void BluetoothProxy::bluetooth_gatt_write(const api::BluetoothGATTWriteRequest &
     return;
   }
 
-  auto err = connection->write_characteristic(msg.handle, msg.data, msg.response);
+  auto err = connection->write_characteristic(msg.handle, msg.data_ptr_, msg.data_len_, msg.response);
   if (err != ESP_OK) {
     this->send_gatt_error(msg.address, msg.handle, err);
   }
@@ -372,7 +372,7 @@ void BluetoothProxy::bluetooth_gatt_write_descriptor(const api::BluetoothGATTWri
     return;
   }
 
-  auto err = connection->write_descriptor(msg.handle, msg.data, true);
+  auto err = connection->write_descriptor(msg.handle, msg.data_ptr_, msg.data_len_, true);
   if (err != ESP_OK) {
     this->send_gatt_error(msg.address, msg.handle, err);
   }
diff --git a/esphome/components/voice_assistant/voice_assistant.cpp b/esphome/components/voice_assistant/voice_assistant.cpp
index 3c69dafa43..01e93dec5e 100644
--- a/esphome/components/voice_assistant/voice_assistant.cpp
+++ b/esphome/components/voice_assistant/voice_assistant.cpp
@@ -273,7 +273,7 @@ void VoiceAssistant::loop() {
         size_t read_bytes = this->ring_buffer_->read((void *) this->send_buffer_, SEND_BUFFER_SIZE, 0);
         if (this->audio_mode_ == AUDIO_MODE_API) {
           api::VoiceAssistantAudio msg;
-          msg.data.assign((char *) this->send_buffer_, read_bytes);
+          msg.set_data(this->send_buffer_, read_bytes);
           this->api_client_->send_message(msg, api::VoiceAssistantAudio::MESSAGE_TYPE);
         } else {
           if (!this->udp_socket_running_) {
@@ -839,12 +839,12 @@ void VoiceAssistant::on_event(const api::VoiceAssistantEventResponse &msg) {
 void VoiceAssistant::on_audio(const api::VoiceAssistantAudio &msg) {
 #ifdef USE_SPEAKER  // We should never get to this function if there is no speaker anyway
   if ((this->speaker_ != nullptr) && (this->speaker_buffer_ != nullptr)) {
-    if (this->speaker_buffer_index_ + msg.data.length() < SPEAKER_BUFFER_SIZE) {
-      memcpy(this->speaker_buffer_ + this->speaker_buffer_index_, msg.data.data(), msg.data.length());
-      this->speaker_buffer_index_ += msg.data.length();
-      this->speaker_buffer_size_ += msg.data.length();
-      this->speaker_bytes_received_ += msg.data.length();
-      ESP_LOGV(TAG, "Received audio: %u bytes from API", msg.data.length());
+    if (this->speaker_buffer_index_ + msg.data_len_ < SPEAKER_BUFFER_SIZE) {
+      memcpy(this->speaker_buffer_ + this->speaker_buffer_index_, msg.data_ptr_, msg.data_len_);
+      this->speaker_buffer_index_ += msg.data_len_;
+      this->speaker_buffer_size_ += msg.data_len_;
+      this->speaker_bytes_received_ += msg.data_len_;
+      ESP_LOGV(TAG, "Received audio: %u bytes from API", msg.data_len_);
     } else {
       ESP_LOGE(TAG, "Cannot receive audio, buffer is full");
     }
diff --git a/script/api_protobuf/api_protobuf.py b/script/api_protobuf/api_protobuf.py
index 5569f29818..213b6fd332 100755
--- a/script/api_protobuf/api_protobuf.py
+++ b/script/api_protobuf/api_protobuf.py
@@ -325,10 +325,6 @@ def create_field_type_info(field: descriptor.FieldDescriptorProto) -> TypeInfo:
     ):
         return FixedArrayBytesType(field, fixed_size)
 
-    # Check for zero_copy option on bytes fields
-    if field.type == 12 and get_field_opt(field, pb.zero_copy, default=False):
-        return ZeroCopyBytesType(field)
-
     validate_field_type(field.type, field.name)
     return TYPE_INFO[field.type](field)
 
@@ -597,32 +593,6 @@ class BytesType(TypeInfo):
     encode_func = "encode_bytes"
     wire_type = WireType.LENGTH_DELIMITED  # Uses wire type 2
 
-    @property
-    def encode_content(self) -> str:
-        return f"buffer.encode_bytes({self.number}, reinterpret_cast<const uint8_t*>(this->{self.field_name}.data()), this->{self.field_name}.size());"
-
-    def dump(self, name: str) -> str:
-        o = f"out.append(format_hex_pretty({name}));"
-        return o
-
-    def get_size_calculation(self, name: str, force: bool = False) -> str:
-        return self._get_simple_size_calculation(name, force, "add_string_field")
-
-    def get_estimated_size(self) -> int:
-        return self.calculate_field_id_size() + 8  # field ID + 8 bytes typical bytes
-
-
-class ZeroCopyBytesType(TypeInfo):
-    """Special type for zero-copy bytes fields that only accepts const uint8_t* data."""
-
-    cpp_type = "std::string"  # Still store as string for compatibility
-    default_value = ""
-    reference_type = "std::string &"
-    const_reference_type = "const std::string &"
-    encode_func = "encode_bytes"
-    wire_type = WireType.LENGTH_DELIMITED
-    decode_length = "value.as_string()"
-
     @property
     def public_content(self) -> list[str]:
         # Store both pointer and length for zero-copy encoding, plus setter method
@@ -637,14 +607,12 @@ class ZeroCopyBytesType(TypeInfo):
 
     @property
     def encode_content(self) -> str:
-        # Encode directly from pointer without nullptr check (like original)
         return f"buffer.encode_bytes({self.number}, this->{self.field_name}_ptr_, this->{self.field_name}_len_);"
 
     def dump(self, name: str) -> str:
         return f"out.append(format_hex_pretty(this->{self.field_name}_ptr_, this->{self.field_name}_len_));"
 
     def get_size_calculation(self, name: str, force: bool = False) -> str:
-        # Use the new add_bytes_field helper
         return f"ProtoSize::add_bytes_field(total_size, {self.calculate_field_id_size()}, this->{self.field_name}_len_);"
 
     def get_estimated_size(self) -> int:

From 1dc736e27aa033e432465cbb02a20e6dd8ff850c Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Sun, 20 Jul 2025 19:28:07 -1000
Subject: [PATCH 04/14] preen

---
 esphome/components/api/api_connection.cpp | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/esphome/components/api/api_connection.cpp b/esphome/components/api/api_connection.cpp
index c3cee7d80d..3031ac58f7 100644
--- a/esphome/components/api/api_connection.cpp
+++ b/esphome/components/api/api_connection.cpp
@@ -231,9 +231,7 @@ void APIConnection::loop() {
     msg.set_data(this->image_reader_->peek_data_buffer(), to_send);
     msg.done = done;
 
-    bool success = this->send_message_(msg, CameraImageResponse::MESSAGE_TYPE);
-
-    if (success) {
+    if (this->send_message_(msg, CameraImageResponse::MESSAGE_TYPE)) {
       this->image_reader_->consume_data(to_send);
       if (done) {
         this->image_reader_->return_image();

From 9cb86241b93d73adcadc2dd09a6c056df8109563 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Sun, 20 Jul 2025 19:40:21 -1000
Subject: [PATCH 05/14] cleanup

---
 esphome/components/api/api_pb2.cpp  |  8 ++++
 esphome/components/api/api_pb2.h    |  4 ++
 script/api_protobuf/api_protobuf.py | 68 ++++++++++++++++++++++-------
 3 files changed, 65 insertions(+), 15 deletions(-)

diff --git a/esphome/components/api/api_pb2.cpp b/esphome/components/api/api_pb2.cpp
index 3b1f8d201f..c3814e8089 100644
--- a/esphome/components/api/api_pb2.cpp
+++ b/esphome/components/api/api_pb2.cpp
@@ -831,6 +831,8 @@ bool NoiseEncryptionSetKeyRequest::decode_length(uint32_t field_id, ProtoLengthD
   switch (field_id) {
     case 1:
       this->key = value.as_string();
+      this->key_ptr_ = reinterpret_cast<const uint8_t *>(this->key.data());
+      this->key_len_ = this->key.size();
       break;
     default:
       return false;
@@ -1999,6 +2001,8 @@ bool BluetoothGATTWriteRequest::decode_length(uint32_t field_id, ProtoLengthDeli
   switch (field_id) {
     case 4:
       this->data = value.as_string();
+      this->data_ptr_ = reinterpret_cast<const uint8_t *>(this->data.data());
+      this->data_len_ = this->data.size();
       break;
     default:
       return false;
@@ -2035,6 +2039,8 @@ bool BluetoothGATTWriteDescriptorRequest::decode_length(uint32_t field_id, Proto
   switch (field_id) {
     case 3:
       this->data = value.as_string();
+      this->data_ptr_ = reinterpret_cast<const uint8_t *>(this->data.data());
+      this->data_len_ = this->data.size();
       break;
     default:
       return false;
@@ -2257,6 +2263,8 @@ bool VoiceAssistantAudio::decode_length(uint32_t field_id, ProtoLengthDelimited
   switch (field_id) {
     case 1:
       this->data = value.as_string();
+      this->data_ptr_ = reinterpret_cast<const uint8_t *>(this->data.data());
+      this->data_len_ = this->data.size();
       break;
     default:
       return false;
diff --git a/esphome/components/api/api_pb2.h b/esphome/components/api/api_pb2.h
index f116cfe4f9..b357b4cf54 100644
--- a/esphome/components/api/api_pb2.h
+++ b/esphome/components/api/api_pb2.h
@@ -993,6 +993,7 @@ class NoiseEncryptionSetKeyRequest : public ProtoDecodableMessage {
 #endif
   const uint8_t *key_ptr_{nullptr};
   size_t key_len_{0};
+  std::string key{};  // Storage for decoded data
   void set_key(const uint8_t *data, size_t len) {
     this->key_ptr_ = data;
     this->key_len_ = len;
@@ -1921,6 +1922,7 @@ class BluetoothGATTWriteRequest : public ProtoDecodableMessage {
   bool response{false};
   const uint8_t *data_ptr_{nullptr};
   size_t data_len_{0};
+  std::string data{};  // Storage for decoded data
   void set_data(const uint8_t *data, size_t len) {
     this->data_ptr_ = data;
     this->data_len_ = len;
@@ -1960,6 +1962,7 @@ class BluetoothGATTWriteDescriptorRequest : public ProtoDecodableMessage {
   uint32_t handle{0};
   const uint8_t *data_ptr_{nullptr};
   size_t data_len_{0};
+  std::string data{};  // Storage for decoded data
   void set_data(const uint8_t *data, size_t len) {
     this->data_ptr_ = data;
     this->data_len_ = len;
@@ -2298,6 +2301,7 @@ class VoiceAssistantAudio : public ProtoDecodableMessage {
 #endif
   const uint8_t *data_ptr_{nullptr};
   size_t data_len_{0};
+  std::string data{};  // Storage for decoded data
   void set_data(const uint8_t *data, size_t len) {
     this->data_ptr_ = data;
     this->data_len_ = len;
diff --git a/script/api_protobuf/api_protobuf.py b/script/api_protobuf/api_protobuf.py
index 213b6fd332..a51fdc233b 100755
--- a/script/api_protobuf/api_protobuf.py
+++ b/script/api_protobuf/api_protobuf.py
@@ -313,7 +313,9 @@ def validate_field_type(field_type: int, field_name: str = "") -> None:
         )
 
 
-def create_field_type_info(field: descriptor.FieldDescriptorProto) -> TypeInfo:
+def create_field_type_info(
+    field: descriptor.FieldDescriptorProto, needs_decode: bool = True
+) -> TypeInfo:
     """Create the appropriate TypeInfo instance for a field, handling repeated fields and custom options."""
     if field.label == 3:  # repeated
         return RepeatedTypeInfo(field)
@@ -325,6 +327,10 @@ def create_field_type_info(field: descriptor.FieldDescriptorProto) -> TypeInfo:
     ):
         return FixedArrayBytesType(field, fixed_size)
 
+    # Special handling for bytes fields
+    if field.type == 12:
+        return BytesType(field, needs_decode)
+
     validate_field_type(field.type, field.name)
     return TYPE_INFO[field.type](field)
 
@@ -589,22 +595,54 @@ class BytesType(TypeInfo):
     default_value = ""
     reference_type = "std::string &"
     const_reference_type = "const std::string &"
-    decode_length = "value.as_string()"
     encode_func = "encode_bytes"
     wire_type = WireType.LENGTH_DELIMITED  # Uses wire type 2
 
+    def __init__(
+        self, field: descriptor.FieldDescriptorProto, needs_decode: bool = True
+    ) -> None:
+        super().__init__(field)
+        self.needs_decode = needs_decode
+
     @property
     def public_content(self) -> list[str]:
         # Store both pointer and length for zero-copy encoding, plus setter method
-        return [
+        content = [
             f"const uint8_t* {self.field_name}_ptr_{{nullptr}};",
             f"size_t {self.field_name}_len_{{0}};",
-            f"void set_{self.field_name}(const uint8_t* data, size_t len) {{",
-            f"  this->{self.field_name}_ptr_ = data;",
-            f"  this->{self.field_name}_len_ = len;",
-            "}",
         ]
 
+        # Only add storage if message needs decoding
+        if self.needs_decode:
+            content.append(
+                f"std::string {self.field_name}{{}};  // Storage for decoded data"
+            )
+
+        content.extend(
+            [
+                f"void set_{self.field_name}(const uint8_t* data, size_t len) {{",
+                f"  this->{self.field_name}_ptr_ = data;",
+                f"  this->{self.field_name}_len_ = len;",
+                "}",
+            ]
+        )
+
+        return content
+
+    @property
+    def decode_length_content(self) -> str:
+        if not self.needs_decode:
+            return ""  # No decode needed for SOURCE_SERVER messages
+
+        # Decode into storage and update pointer/length
+        return (
+            f"case {self.number}:\n"
+            f"  this->{self.field_name} = value.as_string();\n"
+            f"  this->{self.field_name}_ptr_ = reinterpret_cast<const uint8_t*>(this->{self.field_name}.data());\n"
+            f"  this->{self.field_name}_len_ = this->{self.field_name}.size();\n"
+            f"  break;"
+        )
+
     @property
     def encode_content(self) -> str:
         return f"buffer.encode_bytes({self.number}, this->{self.field_name}_ptr_, this->{self.field_name}_len_);"
@@ -1268,7 +1306,7 @@ def build_message_type(
         if field.options.deprecated:
             continue
 
-        ti = create_field_type_info(field)
+        ti = create_field_type_info(field, needs_decode)
 
         # Skip field declarations for fields that are in the base class
         # but include their encode/decode logic
@@ -1583,10 +1621,16 @@ def build_base_class(
     public_content = []
     protected_content = []
 
+    # Determine if any message using this base class needs decoding
+    needs_decode = any(
+        message_source_map.get(msg.name, SOURCE_BOTH) in (SOURCE_BOTH, SOURCE_CLIENT)
+        for msg in messages
+    )
+
     # For base classes, we only declare the fields but don't handle encode/decode
     # The derived classes will handle encoding/decoding with their specific field numbers
     for field in common_fields:
-        ti = create_field_type_info(field)
+        ti = create_field_type_info(field, needs_decode)
 
         # Get field_ifdef if it's consistent across all messages
         field_ifdef = get_common_field_ifdef(field.name, messages)
@@ -1597,12 +1641,6 @@ def build_base_class(
         if ti.public_content:
             public_content.extend(wrap_with_ifdef(ti.public_content, field_ifdef))
 
-    # Determine if any message using this base class needs decoding
-    needs_decode = any(
-        message_source_map.get(msg.name, SOURCE_BOTH) in (SOURCE_BOTH, SOURCE_CLIENT)
-        for msg in messages
-    )
-
     # Build header
     parent_class = "ProtoDecodableMessage" if needs_decode else "ProtoMessage"
     out = f"class {base_class_name} : public {parent_class} {{\n"

From ae7aa4c0efefd257832a9b7bf772afcb3f8ab591 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Sun, 20 Jul 2025 19:46:41 -1000
Subject: [PATCH 06/14] preen

---
 esphome/components/api/api_pb2.cpp  | 8 --------
 script/api_protobuf/api_protobuf.py | 4 +---
 2 files changed, 1 insertion(+), 11 deletions(-)

diff --git a/esphome/components/api/api_pb2.cpp b/esphome/components/api/api_pb2.cpp
index c3814e8089..3b1f8d201f 100644
--- a/esphome/components/api/api_pb2.cpp
+++ b/esphome/components/api/api_pb2.cpp
@@ -831,8 +831,6 @@ bool NoiseEncryptionSetKeyRequest::decode_length(uint32_t field_id, ProtoLengthD
   switch (field_id) {
     case 1:
       this->key = value.as_string();
-      this->key_ptr_ = reinterpret_cast<const uint8_t *>(this->key.data());
-      this->key_len_ = this->key.size();
       break;
     default:
       return false;
@@ -2001,8 +1999,6 @@ bool BluetoothGATTWriteRequest::decode_length(uint32_t field_id, ProtoLengthDeli
   switch (field_id) {
     case 4:
       this->data = value.as_string();
-      this->data_ptr_ = reinterpret_cast<const uint8_t *>(this->data.data());
-      this->data_len_ = this->data.size();
       break;
     default:
       return false;
@@ -2039,8 +2035,6 @@ bool BluetoothGATTWriteDescriptorRequest::decode_length(uint32_t field_id, Proto
   switch (field_id) {
     case 3:
       this->data = value.as_string();
-      this->data_ptr_ = reinterpret_cast<const uint8_t *>(this->data.data());
-      this->data_len_ = this->data.size();
       break;
     default:
       return false;
@@ -2263,8 +2257,6 @@ bool VoiceAssistantAudio::decode_length(uint32_t field_id, ProtoLengthDelimited
   switch (field_id) {
     case 1:
       this->data = value.as_string();
-      this->data_ptr_ = reinterpret_cast<const uint8_t *>(this->data.data());
-      this->data_len_ = this->data.size();
       break;
     default:
       return false;
diff --git a/script/api_protobuf/api_protobuf.py b/script/api_protobuf/api_protobuf.py
index a51fdc233b..adb103b665 100755
--- a/script/api_protobuf/api_protobuf.py
+++ b/script/api_protobuf/api_protobuf.py
@@ -634,12 +634,10 @@ class BytesType(TypeInfo):
         if not self.needs_decode:
             return ""  # No decode needed for SOURCE_SERVER messages
 
-        # Decode into storage and update pointer/length
+        # Decode into storage only - pointer/length are only needed for encoding
         return (
             f"case {self.number}:\n"
             f"  this->{self.field_name} = value.as_string();\n"
-            f"  this->{self.field_name}_ptr_ = reinterpret_cast<const uint8_t*>(this->{self.field_name}.data());\n"
-            f"  this->{self.field_name}_len_ = this->{self.field_name}.size();\n"
             f"  break;"
         )
 

From 8b09a5259e56c3ffc76bc5c78d3e4c42cfd4d07c Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Sun, 20 Jul 2025 19:48:19 -1000
Subject: [PATCH 07/14] preen

---
 esphome/components/bluetooth_proxy/bluetooth_proxy.cpp | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/esphome/components/bluetooth_proxy/bluetooth_proxy.cpp b/esphome/components/bluetooth_proxy/bluetooth_proxy.cpp
index 66423d201d..e5bc626d1b 100644
--- a/esphome/components/bluetooth_proxy/bluetooth_proxy.cpp
+++ b/esphome/components/bluetooth_proxy/bluetooth_proxy.cpp
@@ -344,7 +344,8 @@ void BluetoothProxy::bluetooth_gatt_write(const api::BluetoothGATTWriteRequest &
     return;
   }
 
-  auto err = connection->write_characteristic(msg.handle, msg.data_ptr_, msg.data_len_, msg.response);
+  auto err = connection->write_characteristic(msg.handle, reinterpret_cast<const uint8_t *>(msg.data.data()),
+                                              msg.data.size(), msg.response);
   if (err != ESP_OK) {
     this->send_gatt_error(msg.address, msg.handle, err);
   }
@@ -372,7 +373,8 @@ void BluetoothProxy::bluetooth_gatt_write_descriptor(const api::BluetoothGATTWri
     return;
   }
 
-  auto err = connection->write_descriptor(msg.handle, msg.data_ptr_, msg.data_len_, true);
+  auto err = connection->write_descriptor(msg.handle, reinterpret_cast<const uint8_t *>(msg.data.data()),
+                                          msg.data.size(), true);
   if (err != ESP_OK) {
     this->send_gatt_error(msg.address, msg.handle, err);
   }

From 5fb97e8e3ce720e2431aea1b36799548247367fc Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Sun, 20 Jul 2025 19:50:55 -1000
Subject: [PATCH 08/14] preen

---
 esphome/components/api/api_connection.cpp            |  4 +---
 .../bluetooth_proxy/bluetooth_connection.cpp         |  9 ++++-----
 .../bluetooth_proxy/bluetooth_connection.h           |  4 ++--
 .../components/bluetooth_proxy/bluetooth_proxy.cpp   |  6 ++----
 .../components/voice_assistant/voice_assistant.cpp   | 12 ++++++------
 5 files changed, 15 insertions(+), 20 deletions(-)

diff --git a/esphome/components/api/api_connection.cpp b/esphome/components/api/api_connection.cpp
index 3031ac58f7..61fff064b2 100644
--- a/esphome/components/api/api_connection.cpp
+++ b/esphome/components/api/api_connection.cpp
@@ -1495,9 +1495,7 @@ void APIConnection::execute_service(const ExecuteServiceRequest &msg) {
 NoiseEncryptionSetKeyResponse APIConnection::noise_encryption_set_key(const NoiseEncryptionSetKeyRequest &msg) {
   psk_t psk{};
   NoiseEncryptionSetKeyResponse resp;
-  // Create temporary string from pointer/length for base64_decode
-  std::string key_str(reinterpret_cast<const char *>(msg.key_ptr_), msg.key_len_);
-  if (base64_decode(key_str, psk.data(), key_str.size()) != psk.size()) {
+  if (base64_decode(msg.key, psk.data(), msg.key.size()) != psk.size()) {
     ESP_LOGW(TAG, "Invalid encryption key length");
     resp.success = false;
     return resp;
diff --git a/esphome/components/bluetooth_proxy/bluetooth_connection.cpp b/esphome/components/bluetooth_proxy/bluetooth_connection.cpp
index 8e08d62504..b3b271a027 100644
--- a/esphome/components/bluetooth_proxy/bluetooth_connection.cpp
+++ b/esphome/components/bluetooth_proxy/bluetooth_connection.cpp
@@ -333,8 +333,7 @@ esp_err_t BluetoothConnection::read_characteristic(uint16_t handle) {
   return ESP_OK;
 }
 
-esp_err_t BluetoothConnection::write_characteristic(uint16_t handle, const uint8_t *data, size_t data_len,
-                                                    bool response) {
+esp_err_t BluetoothConnection::write_characteristic(uint16_t handle, const std::string &data, bool response) {
   if (!this->connected()) {
     ESP_LOGW(TAG, "[%d] [%s] Cannot write GATT characteristic, not connected.", this->connection_index_,
              this->address_str_.c_str());
@@ -344,7 +343,7 @@ esp_err_t BluetoothConnection::write_characteristic(uint16_t handle, const uint8
            handle);
 
   esp_err_t err =
-      esp_ble_gattc_write_char(this->gattc_if_, this->conn_id_, handle, data_len, const_cast<uint8_t *>(data),
+      esp_ble_gattc_write_char(this->gattc_if_, this->conn_id_, handle, data.size(), (uint8_t *) data.data(),
                                response ? ESP_GATT_WRITE_TYPE_RSP : ESP_GATT_WRITE_TYPE_NO_RSP, ESP_GATT_AUTH_REQ_NONE);
   if (err != ERR_OK) {
     ESP_LOGW(TAG, "[%d] [%s] esp_ble_gattc_write_char error, err=%d", this->connection_index_,
@@ -372,7 +371,7 @@ esp_err_t BluetoothConnection::read_descriptor(uint16_t handle) {
   return ESP_OK;
 }
 
-esp_err_t BluetoothConnection::write_descriptor(uint16_t handle, const uint8_t *data, size_t data_len, bool response) {
+esp_err_t BluetoothConnection::write_descriptor(uint16_t handle, const std::string &data, bool response) {
   if (!this->connected()) {
     ESP_LOGW(TAG, "[%d] [%s] Cannot write GATT descriptor, not connected.", this->connection_index_,
              this->address_str_.c_str());
@@ -382,7 +381,7 @@ esp_err_t BluetoothConnection::write_descriptor(uint16_t handle, const uint8_t *
            handle);
 
   esp_err_t err = esp_ble_gattc_write_char_descr(
-      this->gattc_if_, this->conn_id_, handle, data_len, const_cast<uint8_t *>(data),
+      this->gattc_if_, this->conn_id_, handle, data.size(), (uint8_t *) data.data(),
       response ? ESP_GATT_WRITE_TYPE_RSP : ESP_GATT_WRITE_TYPE_NO_RSP, ESP_GATT_AUTH_REQ_NONE);
   if (err != ERR_OK) {
     ESP_LOGW(TAG, "[%d] [%s] esp_ble_gattc_write_char_descr error, err=%d", this->connection_index_,
diff --git a/esphome/components/bluetooth_proxy/bluetooth_connection.h b/esphome/components/bluetooth_proxy/bluetooth_connection.h
index c9c4b7c901..2673238fba 100644
--- a/esphome/components/bluetooth_proxy/bluetooth_connection.h
+++ b/esphome/components/bluetooth_proxy/bluetooth_connection.h
@@ -19,9 +19,9 @@ class BluetoothConnection : public esp32_ble_client::BLEClientBase {
   esp32_ble_tracker::AdvertisementParserType get_advertisement_parser_type() override;
 
   esp_err_t read_characteristic(uint16_t handle);
-  esp_err_t write_characteristic(uint16_t handle, const uint8_t *data, size_t data_len, bool response);
+  esp_err_t write_characteristic(uint16_t handle, const std::string &data, bool response);
   esp_err_t read_descriptor(uint16_t handle);
-  esp_err_t write_descriptor(uint16_t handle, const uint8_t *data, size_t data_len, bool response);
+  esp_err_t write_descriptor(uint16_t handle, const std::string &data, bool response);
 
   esp_err_t notify_characteristic(uint16_t handle, bool enable);
 
diff --git a/esphome/components/bluetooth_proxy/bluetooth_proxy.cpp b/esphome/components/bluetooth_proxy/bluetooth_proxy.cpp
index e5bc626d1b..8a1a2bff6a 100644
--- a/esphome/components/bluetooth_proxy/bluetooth_proxy.cpp
+++ b/esphome/components/bluetooth_proxy/bluetooth_proxy.cpp
@@ -344,8 +344,7 @@ void BluetoothProxy::bluetooth_gatt_write(const api::BluetoothGATTWriteRequest &
     return;
   }
 
-  auto err = connection->write_characteristic(msg.handle, reinterpret_cast<const uint8_t *>(msg.data.data()),
-                                              msg.data.size(), msg.response);
+  auto err = connection->write_characteristic(msg.handle, msg.data, msg.response);
   if (err != ESP_OK) {
     this->send_gatt_error(msg.address, msg.handle, err);
   }
@@ -373,8 +372,7 @@ void BluetoothProxy::bluetooth_gatt_write_descriptor(const api::BluetoothGATTWri
     return;
   }
 
-  auto err = connection->write_descriptor(msg.handle, reinterpret_cast<const uint8_t *>(msg.data.data()),
-                                          msg.data.size(), true);
+  auto err = connection->write_descriptor(msg.handle, msg.data, true);
   if (err != ESP_OK) {
     this->send_gatt_error(msg.address, msg.handle, err);
   }
diff --git a/esphome/components/voice_assistant/voice_assistant.cpp b/esphome/components/voice_assistant/voice_assistant.cpp
index 01e93dec5e..c35a0814b8 100644
--- a/esphome/components/voice_assistant/voice_assistant.cpp
+++ b/esphome/components/voice_assistant/voice_assistant.cpp
@@ -839,12 +839,12 @@ void VoiceAssistant::on_event(const api::VoiceAssistantEventResponse &msg) {
 void VoiceAssistant::on_audio(const api::VoiceAssistantAudio &msg) {
 #ifdef USE_SPEAKER  // We should never get to this function if there is no speaker anyway
   if ((this->speaker_ != nullptr) && (this->speaker_buffer_ != nullptr)) {
-    if (this->speaker_buffer_index_ + msg.data_len_ < SPEAKER_BUFFER_SIZE) {
-      memcpy(this->speaker_buffer_ + this->speaker_buffer_index_, msg.data_ptr_, msg.data_len_);
-      this->speaker_buffer_index_ += msg.data_len_;
-      this->speaker_buffer_size_ += msg.data_len_;
-      this->speaker_bytes_received_ += msg.data_len_;
-      ESP_LOGV(TAG, "Received audio: %u bytes from API", msg.data_len_);
+    if (this->speaker_buffer_index_ + msg.data.size() < SPEAKER_BUFFER_SIZE) {
+      memcpy(this->speaker_buffer_ + this->speaker_buffer_index_, msg.data.data(), msg.data.size());
+      this->speaker_buffer_index_ += msg.data.size();
+      this->speaker_buffer_size_ += msg.data.size();
+      this->speaker_bytes_received_ += msg.data.size();
+      ESP_LOGV(TAG, "Received audio: %u bytes from API", msg.data.size());
     } else {
       ESP_LOGE(TAG, "Cannot receive audio, buffer is full");
     }

From 8b74333e8b66ddfbf435aca652f20adf28a4b512 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Sun, 20 Jul 2025 19:52:26 -1000
Subject: [PATCH 09/14] preen

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

diff --git a/esphome/components/voice_assistant/voice_assistant.cpp b/esphome/components/voice_assistant/voice_assistant.cpp
index c35a0814b8..481a4efa62 100644
--- a/esphome/components/voice_assistant/voice_assistant.cpp
+++ b/esphome/components/voice_assistant/voice_assistant.cpp
@@ -839,12 +839,12 @@ void VoiceAssistant::on_event(const api::VoiceAssistantEventResponse &msg) {
 void VoiceAssistant::on_audio(const api::VoiceAssistantAudio &msg) {
 #ifdef USE_SPEAKER  // We should never get to this function if there is no speaker anyway
   if ((this->speaker_ != nullptr) && (this->speaker_buffer_ != nullptr)) {
-    if (this->speaker_buffer_index_ + msg.data.size() < SPEAKER_BUFFER_SIZE) {
-      memcpy(this->speaker_buffer_ + this->speaker_buffer_index_, msg.data.data(), msg.data.size());
-      this->speaker_buffer_index_ += msg.data.size();
-      this->speaker_buffer_size_ += msg.data.size();
-      this->speaker_bytes_received_ += msg.data.size();
-      ESP_LOGV(TAG, "Received audio: %u bytes from API", msg.data.size());
+    if (this->speaker_buffer_index_ + msg.data.length() < SPEAKER_BUFFER_SIZE) {
+      memcpy(this->speaker_buffer_ + this->speaker_buffer_index_, msg.data.data(), msg.data.length());
+      this->speaker_buffer_index_ += msg.data.length();
+      this->speaker_buffer_size_ += msg.data.length();
+      this->speaker_bytes_received_ += msg.data.length();
+      ESP_LOGV(TAG, "Received audio: %u bytes from API", msg.data.length());
     } else {
       ESP_LOGE(TAG, "Cannot receive audio, buffer is full");
     }

From 04953db51e3b0d1bca762591c0ba4f50a5955e2c Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Sun, 20 Jul 2025 19:56:42 -1000
Subject: [PATCH 10/14] cleanup

---
 esphome/components/api/api_pb2.h    | 18 ---------
 script/api_protobuf/api_protobuf.py | 57 +++++++++++++++++++----------
 2 files changed, 37 insertions(+), 38 deletions(-)

diff --git a/esphome/components/api/api_pb2.h b/esphome/components/api/api_pb2.h
index b357b4cf54..728250baf4 100644
--- a/esphome/components/api/api_pb2.h
+++ b/esphome/components/api/api_pb2.h
@@ -991,13 +991,7 @@ class NoiseEncryptionSetKeyRequest : public ProtoDecodableMessage {
 #ifdef HAS_PROTO_MESSAGE_DUMP
   const char *message_name() const override { return "noise_encryption_set_key_request"; }
 #endif
-  const uint8_t *key_ptr_{nullptr};
-  size_t key_len_{0};
   std::string key{};  // Storage for decoded data
-  void set_key(const uint8_t *data, size_t len) {
-    this->key_ptr_ = data;
-    this->key_len_ = len;
-  }
 #ifdef HAS_PROTO_MESSAGE_DUMP
   void dump_to(std::string &out) const override;
 #endif
@@ -1920,13 +1914,7 @@ class BluetoothGATTWriteRequest : public ProtoDecodableMessage {
   uint64_t address{0};
   uint32_t handle{0};
   bool response{false};
-  const uint8_t *data_ptr_{nullptr};
-  size_t data_len_{0};
   std::string data{};  // Storage for decoded data
-  void set_data(const uint8_t *data, size_t len) {
-    this->data_ptr_ = data;
-    this->data_len_ = len;
-  }
 #ifdef HAS_PROTO_MESSAGE_DUMP
   void dump_to(std::string &out) const override;
 #endif
@@ -1960,13 +1948,7 @@ class BluetoothGATTWriteDescriptorRequest : public ProtoDecodableMessage {
 #endif
   uint64_t address{0};
   uint32_t handle{0};
-  const uint8_t *data_ptr_{nullptr};
-  size_t data_len_{0};
   std::string data{};  // Storage for decoded data
-  void set_data(const uint8_t *data, size_t len) {
-    this->data_ptr_ = data;
-    this->data_len_ = len;
-  }
 #ifdef HAS_PROTO_MESSAGE_DUMP
   void dump_to(std::string &out) const override;
 #endif
diff --git a/script/api_protobuf/api_protobuf.py b/script/api_protobuf/api_protobuf.py
index adb103b665..4b6ed891a8 100755
--- a/script/api_protobuf/api_protobuf.py
+++ b/script/api_protobuf/api_protobuf.py
@@ -314,7 +314,9 @@ def validate_field_type(field_type: int, field_name: str = "") -> None:
 
 
 def create_field_type_info(
-    field: descriptor.FieldDescriptorProto, needs_decode: bool = True
+    field: descriptor.FieldDescriptorProto,
+    needs_decode: bool = True,
+    needs_encode: bool = True,
 ) -> TypeInfo:
     """Create the appropriate TypeInfo instance for a field, handling repeated fields and custom options."""
     if field.label == 3:  # repeated
@@ -329,7 +331,7 @@ def create_field_type_info(
 
     # Special handling for bytes fields
     if field.type == 12:
-        return BytesType(field, needs_decode)
+        return BytesType(field, needs_decode, needs_encode)
 
     validate_field_type(field.type, field.name)
     return TYPE_INFO[field.type](field)
@@ -599,33 +601,44 @@ class BytesType(TypeInfo):
     wire_type = WireType.LENGTH_DELIMITED  # Uses wire type 2
 
     def __init__(
-        self, field: descriptor.FieldDescriptorProto, needs_decode: bool = True
+        self,
+        field: descriptor.FieldDescriptorProto,
+        needs_decode: bool = True,
+        needs_encode: bool = True,
     ) -> None:
         super().__init__(field)
         self.needs_decode = needs_decode
+        self.needs_encode = needs_encode
 
     @property
     def public_content(self) -> list[str]:
-        # Store both pointer and length for zero-copy encoding, plus setter method
-        content = [
-            f"const uint8_t* {self.field_name}_ptr_{{nullptr}};",
-            f"size_t {self.field_name}_len_{{0}};",
-        ]
+        content = []
 
-        # Only add storage if message needs decoding
+        # Add pointer/length fields if message needs encoding
+        if self.needs_encode:
+            content.extend(
+                [
+                    f"const uint8_t* {self.field_name}_ptr_{{nullptr}};",
+                    f"size_t {self.field_name}_len_{{0}};",
+                ]
+            )
+
+        # Add std::string storage if message needs decoding
         if self.needs_decode:
             content.append(
                 f"std::string {self.field_name}{{}};  // Storage for decoded data"
             )
 
-        content.extend(
-            [
-                f"void set_{self.field_name}(const uint8_t* data, size_t len) {{",
-                f"  this->{self.field_name}_ptr_ = data;",
-                f"  this->{self.field_name}_len_ = len;",
-                "}",
-            ]
-        )
+        # Add setter method if message needs encoding
+        if self.needs_encode:
+            content.extend(
+                [
+                    f"void set_{self.field_name}(const uint8_t* data, size_t len) {{",
+                    f"  this->{self.field_name}_ptr_ = data;",
+                    f"  this->{self.field_name}_len_ = len;",
+                    "}",
+                ]
+            )
 
         return content
 
@@ -1304,7 +1317,7 @@ def build_message_type(
         if field.options.deprecated:
             continue
 
-        ti = create_field_type_info(field, needs_decode)
+        ti = create_field_type_info(field, needs_decode, needs_encode)
 
         # Skip field declarations for fields that are in the base class
         # but include their encode/decode logic
@@ -1619,16 +1632,20 @@ def build_base_class(
     public_content = []
     protected_content = []
 
-    # Determine if any message using this base class needs decoding
+    # Determine if any message using this base class needs decoding/encoding
     needs_decode = any(
         message_source_map.get(msg.name, SOURCE_BOTH) in (SOURCE_BOTH, SOURCE_CLIENT)
         for msg in messages
     )
+    needs_encode = any(
+        message_source_map.get(msg.name, SOURCE_BOTH) in (SOURCE_BOTH, SOURCE_SERVER)
+        for msg in messages
+    )
 
     # For base classes, we only declare the fields but don't handle encode/decode
     # The derived classes will handle encoding/decoding with their specific field numbers
     for field in common_fields:
-        ti = create_field_type_info(field, needs_decode)
+        ti = create_field_type_info(field, needs_decode, needs_encode)
 
         # Get field_ifdef if it's consistent across all messages
         field_ifdef = get_common_field_ifdef(field.name, messages)

From ad52d80281239da9aea108e1de256b909ef3bddf Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Sun, 20 Jul 2025 19:57:32 -1000
Subject: [PATCH 11/14] cleanup

---
 esphome/components/api/api_pb2.h    | 8 ++++----
 script/api_protobuf/api_protobuf.py | 4 +---
 2 files changed, 5 insertions(+), 7 deletions(-)

diff --git a/esphome/components/api/api_pb2.h b/esphome/components/api/api_pb2.h
index 728250baf4..1f91c5c179 100644
--- a/esphome/components/api/api_pb2.h
+++ b/esphome/components/api/api_pb2.h
@@ -991,7 +991,7 @@ class NoiseEncryptionSetKeyRequest : public ProtoDecodableMessage {
 #ifdef HAS_PROTO_MESSAGE_DUMP
   const char *message_name() const override { return "noise_encryption_set_key_request"; }
 #endif
-  std::string key{};  // Storage for decoded data
+  std::string key{};
 #ifdef HAS_PROTO_MESSAGE_DUMP
   void dump_to(std::string &out) const override;
 #endif
@@ -1914,7 +1914,7 @@ class BluetoothGATTWriteRequest : public ProtoDecodableMessage {
   uint64_t address{0};
   uint32_t handle{0};
   bool response{false};
-  std::string data{};  // Storage for decoded data
+  std::string data{};
 #ifdef HAS_PROTO_MESSAGE_DUMP
   void dump_to(std::string &out) const override;
 #endif
@@ -1948,7 +1948,7 @@ class BluetoothGATTWriteDescriptorRequest : public ProtoDecodableMessage {
 #endif
   uint64_t address{0};
   uint32_t handle{0};
-  std::string data{};  // Storage for decoded data
+  std::string data{};
 #ifdef HAS_PROTO_MESSAGE_DUMP
   void dump_to(std::string &out) const override;
 #endif
@@ -2283,7 +2283,7 @@ class VoiceAssistantAudio : public ProtoDecodableMessage {
 #endif
   const uint8_t *data_ptr_{nullptr};
   size_t data_len_{0};
-  std::string data{};  // Storage for decoded data
+  std::string data{};
   void set_data(const uint8_t *data, size_t len) {
     this->data_ptr_ = data;
     this->data_len_ = len;
diff --git a/script/api_protobuf/api_protobuf.py b/script/api_protobuf/api_protobuf.py
index 4b6ed891a8..b23f788256 100755
--- a/script/api_protobuf/api_protobuf.py
+++ b/script/api_protobuf/api_protobuf.py
@@ -625,9 +625,7 @@ class BytesType(TypeInfo):
 
         # Add std::string storage if message needs decoding
         if self.needs_decode:
-            content.append(
-                f"std::string {self.field_name}{{}};  // Storage for decoded data"
-            )
+            content.append(f"std::string {self.field_name}{{}};")
 
         # Add setter method if message needs encoding
         if self.needs_encode:

From 5e906b1dd935fd8ffefade1e46aebc1568022863 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Sun, 20 Jul 2025 20:06:50 -1000
Subject: [PATCH 12/14] cleanup

---
 esphome/components/api/api_pb2_dump.cpp | 6 +++---
 script/api_protobuf/api_protobuf.py     | 6 +++++-
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/esphome/components/api/api_pb2_dump.cpp b/esphome/components/api/api_pb2_dump.cpp
index 7eb0da6a6f..bf4ca5e402 100644
--- a/esphome/components/api/api_pb2_dump.cpp
+++ b/esphome/components/api/api_pb2_dump.cpp
@@ -1679,7 +1679,7 @@ void NoiseEncryptionSetKeyRequest::dump_to(std::string &out) const {
   __attribute__((unused)) char buffer[64];
   out.append("NoiseEncryptionSetKeyRequest {\n");
   out.append("  key: ");
-  out.append(format_hex_pretty(this->key_ptr_, this->key_len_));
+  out.append(format_hex_pretty(reinterpret_cast<const uint8_t *>(this->key.data()), this->key.size()));
   out.append("\n");
   out.append("}");
 }
@@ -3163,7 +3163,7 @@ void BluetoothGATTWriteRequest::dump_to(std::string &out) const {
   out.append("\n");
 
   out.append("  data: ");
-  out.append(format_hex_pretty(this->data_ptr_, this->data_len_));
+  out.append(format_hex_pretty(reinterpret_cast<const uint8_t *>(this->data.data()), this->data.size()));
   out.append("\n");
   out.append("}");
 }
@@ -3195,7 +3195,7 @@ void BluetoothGATTWriteDescriptorRequest::dump_to(std::string &out) const {
   out.append("\n");
 
   out.append("  data: ");
-  out.append(format_hex_pretty(this->data_ptr_, this->data_len_));
+  out.append(format_hex_pretty(reinterpret_cast<const uint8_t *>(this->data.data()), this->data.size()));
   out.append("\n");
   out.append("}");
 }
diff --git a/script/api_protobuf/api_protobuf.py b/script/api_protobuf/api_protobuf.py
index b23f788256..298f0a6d18 100755
--- a/script/api_protobuf/api_protobuf.py
+++ b/script/api_protobuf/api_protobuf.py
@@ -657,7 +657,11 @@ class BytesType(TypeInfo):
         return f"buffer.encode_bytes({self.number}, this->{self.field_name}_ptr_, this->{self.field_name}_len_);"
 
     def dump(self, name: str) -> str:
-        return f"out.append(format_hex_pretty(this->{self.field_name}_ptr_, this->{self.field_name}_len_));"
+        # Use pointer/length if available (SOURCE_SERVER/SOURCE_BOTH), otherwise use std::string
+        if self.needs_encode:
+            return f"out.append(format_hex_pretty(this->{self.field_name}_ptr_, this->{self.field_name}_len_));"
+        else:
+            return f"out.append(format_hex_pretty(reinterpret_cast<const uint8_t*>(this->{self.field_name}.data()), this->{self.field_name}.size()));"
 
     def get_size_calculation(self, name: str, force: bool = False) -> str:
         return f"ProtoSize::add_bytes_field(total_size, {self.calculate_field_id_size()}, this->{self.field_name}_len_);"

From b24ff7236e3010c64b81b8405ab142d718ba9775 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Sun, 20 Jul 2025 20:07:30 -1000
Subject: [PATCH 13/14] cleanup

---
 esphome/components/api/api_pb2_dump.cpp |  6 +++++-
 script/api_protobuf/api_protobuf.py     | 19 +++++++++++++++----
 2 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/esphome/components/api/api_pb2_dump.cpp b/esphome/components/api/api_pb2_dump.cpp
index bf4ca5e402..e5120007ae 100644
--- a/esphome/components/api/api_pb2_dump.cpp
+++ b/esphome/components/api/api_pb2_dump.cpp
@@ -3485,7 +3485,11 @@ void VoiceAssistantAudio::dump_to(std::string &out) const {
   __attribute__((unused)) char buffer[64];
   out.append("VoiceAssistantAudio {\n");
   out.append("  data: ");
-  out.append(format_hex_pretty(this->data_ptr_, this->data_len_));
+  if (this->data_ptr_ != nullptr) {
+    out.append(format_hex_pretty(this->data_ptr_, this->data_len_));
+  } else {
+    out.append(format_hex_pretty(reinterpret_cast<const uint8_t *>(this->data.data()), this->data.size()));
+  }
   out.append("\n");
 
   out.append("  end: ");
diff --git a/script/api_protobuf/api_protobuf.py b/script/api_protobuf/api_protobuf.py
index 298f0a6d18..0cfa7fc344 100755
--- a/script/api_protobuf/api_protobuf.py
+++ b/script/api_protobuf/api_protobuf.py
@@ -657,12 +657,23 @@ class BytesType(TypeInfo):
         return f"buffer.encode_bytes({self.number}, this->{self.field_name}_ptr_, this->{self.field_name}_len_);"
 
     def dump(self, name: str) -> str:
-        # Use pointer/length if available (SOURCE_SERVER/SOURCE_BOTH), otherwise use std::string
-        if self.needs_encode:
-            return f"out.append(format_hex_pretty(this->{self.field_name}_ptr_, this->{self.field_name}_len_));"
-        else:
+        # For SOURCE_CLIENT only, always use std::string
+        if not self.needs_encode:
             return f"out.append(format_hex_pretty(reinterpret_cast<const uint8_t*>(this->{self.field_name}.data()), this->{self.field_name}.size()));"
 
+        # For SOURCE_SERVER, always use pointer/length
+        if not self.needs_decode:
+            return f"out.append(format_hex_pretty(this->{self.field_name}_ptr_, this->{self.field_name}_len_));"
+
+        # For SOURCE_BOTH, check if pointer is set (sending) or use string (received)
+        return (
+            f"if (this->{self.field_name}_ptr_ != nullptr) {{\n"
+            f"    out.append(format_hex_pretty(this->{self.field_name}_ptr_, this->{self.field_name}_len_));\n"
+            f"  }} else {{\n"
+            f"    out.append(format_hex_pretty(reinterpret_cast<const uint8_t*>(this->{self.field_name}.data()), this->{self.field_name}.size()));\n"
+            f"  }}"
+        )
+
     def get_size_calculation(self, name: str, force: bool = False) -> str:
         return f"ProtoSize::add_bytes_field(total_size, {self.calculate_field_id_size()}, this->{self.field_name}_len_);"
 

From 8c11241af03010d967dbaaf9e4774352035bee73 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Sun, 20 Jul 2025 20:08:57 -1000
Subject: [PATCH 14/14] cleanup

---
 script/api_protobuf/api_protobuf.py | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/script/api_protobuf/api_protobuf.py b/script/api_protobuf/api_protobuf.py
index 0cfa7fc344..96471d33b2 100755
--- a/script/api_protobuf/api_protobuf.py
+++ b/script/api_protobuf/api_protobuf.py
@@ -657,20 +657,23 @@ class BytesType(TypeInfo):
         return f"buffer.encode_bytes({self.number}, this->{self.field_name}_ptr_, this->{self.field_name}_len_);"
 
     def dump(self, name: str) -> str:
+        ptr_dump = f"format_hex_pretty(this->{self.field_name}_ptr_, this->{self.field_name}_len_)"
+        str_dump = f"format_hex_pretty(reinterpret_cast<const uint8_t*>(this->{self.field_name}.data()), this->{self.field_name}.size())"
+
         # For SOURCE_CLIENT only, always use std::string
         if not self.needs_encode:
-            return f"out.append(format_hex_pretty(reinterpret_cast<const uint8_t*>(this->{self.field_name}.data()), this->{self.field_name}.size()));"
+            return f"out.append({str_dump});"
 
         # For SOURCE_SERVER, always use pointer/length
         if not self.needs_decode:
-            return f"out.append(format_hex_pretty(this->{self.field_name}_ptr_, this->{self.field_name}_len_));"
+            return f"out.append({ptr_dump});"
 
         # For SOURCE_BOTH, check if pointer is set (sending) or use string (received)
         return (
             f"if (this->{self.field_name}_ptr_ != nullptr) {{\n"
-            f"    out.append(format_hex_pretty(this->{self.field_name}_ptr_, this->{self.field_name}_len_));\n"
+            f"    out.append({ptr_dump});\n"
             f"  }} else {{\n"
-            f"    out.append(format_hex_pretty(reinterpret_cast<const uint8_t*>(this->{self.field_name}.data()), this->{self.field_name}.size()));\n"
+            f"    out.append({str_dump});\n"
             f"  }}"
         )