diff --git a/lib/openai/base_stream.rb b/lib/openai/base_stream.rb
index 082d045d..c2beb4b9 100644
--- a/lib/openai/base_stream.rb
+++ b/lib/openai/base_stream.rb
@@ -16,7 +16,7 @@ module OpenAI
   #
   # messages => Array
   # ```
-  class BaseStream
+  module BaseStream
     # @return [void]
     #
     def close = OpenAI::Util.close_fused!(@iterator)
diff --git a/lib/openai/stream.rb b/lib/openai/stream.rb
index 801b6247..f9319992 100644
--- a/lib/openai/stream.rb
+++ b/lib/openai/stream.rb
@@ -16,7 +16,9 @@ module OpenAI
   #
   # messages => Array
   # ```
-  class Stream < OpenAI::BaseStream
+  class Stream
+    include OpenAI::BaseStream
+
     # @private
     #
     # @return [Enumerable]
diff --git a/rbi/lib/openai/base_client.rbi b/rbi/lib/openai/base_client.rbi
index ae1f372e..fd80c3c5 100644
--- a/rbi/lib/openai/base_client.rbi
+++ b/rbi/lib/openai/base_client.rbi
@@ -22,7 +22,7 @@ module OpenAI
         body: T.nilable(T.anything),
         unwrap: T.nilable(Symbol),
         page: T.nilable(T::Class[OpenAI::BasePage[OpenAI::BaseModel]]),
-        stream: T.nilable(T::Class[OpenAI::BaseStream[OpenAI::BaseModel]]),
+        stream: T.nilable(T::Class[OpenAI::BaseStream[T.anything, OpenAI::BaseModel]]),
         model: T.nilable(OpenAI::Converter::Input),
         options: T.nilable(T.any(OpenAI::RequestOptions, T::Hash[Symbol, T.anything]))
       }
@@ -148,7 +148,7 @@ module OpenAI
         body: T.nilable(T.anything),
         unwrap: T.nilable(Symbol),
         page: T.nilable(T::Class[OpenAI::BasePage[OpenAI::BaseModel]]),
-        stream: T.nilable(T::Class[OpenAI::BaseStream[OpenAI::BaseModel]]),
+        stream: T.nilable(T::Class[OpenAI::BaseStream[T.anything, OpenAI::BaseModel]]),
         model: T.nilable(OpenAI::Converter::Input),
         options: T.nilable(T.any(OpenAI::RequestOptions, T::Hash[Symbol, T.anything]))
       )
diff --git a/rbi/lib/openai/base_stream.rbi b/rbi/lib/openai/base_stream.rbi
index f527b849..8b829bd1 100644
--- a/rbi/lib/openai/base_stream.rbi
+++ b/rbi/lib/openai/base_stream.rbi
@@ -1,7 +1,8 @@
 # typed: strong
 
 module OpenAI
-  class BaseStream
+  module BaseStream
+    Message = type_member(:in)
     Elem = type_member(:out)
 
     sig { void }
@@ -28,11 +29,11 @@ module OpenAI
         url: URI::Generic,
         status: Integer,
         response: Net::HTTPResponse,
-        messages: T::Enumerable[OpenAI::Util::SSEMessage]
+        messages: T::Enumerable[Message]
       )
-        .returns(T.attached_class)
+        .void
     end
-    def self.new(model:, url:, status:, response:, messages:)
+    def initialize(model:, url:, status:, response:, messages:)
     end
   end
 end
diff --git a/rbi/lib/openai/stream.rbi b/rbi/lib/openai/stream.rbi
index f4bf6fa9..3dc46e28 100644
--- a/rbi/lib/openai/stream.rbi
+++ b/rbi/lib/openai/stream.rbi
@@ -1,11 +1,27 @@
 # typed: strong
 
 module OpenAI
-  class Stream < OpenAI::BaseStream
+  class Stream
+    include OpenAI::BaseStream
+
+    Message = type_member(:in) { {fixed: OpenAI::Util::SSEMessage} }
     Elem = type_member(:out)
 
     sig { override.returns(T::Enumerable[Elem]) }
     private def iterator
     end
+
+    sig do
+      params(
+        model: T.any(T::Class[T.anything], OpenAI::Converter),
+        url: URI::Generic,
+        status: Integer,
+        response: Net::HTTPResponse,
+        messages: T::Enumerable[OpenAI::Util::SSEMessage]
+      )
+        .returns(T.attached_class)
+    end
+    def self.new(model:, url:, status:, response:, messages:)
+    end
   end
 end
diff --git a/sig/openai/base_stream.rbs b/sig/openai/base_stream.rbs
index 397d46e5..e5d9ec89 100644
--- a/sig/openai/base_stream.rbs
+++ b/sig/openai/base_stream.rbs
@@ -1,5 +1,5 @@
 module OpenAI
-  class BaseStream[Elem]
+  module BaseStream[Message, Elem]
     def close: -> void
 
     private def iterator: -> Enumerable[Elem]
@@ -15,7 +15,7 @@ module OpenAI
       url: URI::Generic,
       status: Integer,
       response: top,
-      messages: Enumerable[OpenAI::Util::sse_message]
+      messages: Enumerable[Message]
     ) -> void
   end
 end
diff --git a/sig/openai/stream.rbs b/sig/openai/stream.rbs
index 78d58b92..675ecb74 100644
--- a/sig/openai/stream.rbs
+++ b/sig/openai/stream.rbs
@@ -1,5 +1,15 @@
 module OpenAI
-  class Stream[Elem] < OpenAI::BaseStream[Elem]
+  class Stream[Elem]
+    include OpenAI::BaseStream[OpenAI::Util::sse_message, Elem]
+
     private def iterator: -> Enumerable[Elem]
+
+    def initialize: (
+      model: Class | OpenAI::Converter,
+      url: URI::Generic,
+      status: Integer,
+      response: top,
+      messages: Enumerable[OpenAI::Util::sse_message]
+    ) -> void
   end
 end