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)