diff --git a/libs/langchain/langchain_classic/callbacks/streaming_aiter.py b/libs/langchain/langchain_classic/callbacks/streaming_aiter.py
index a0aa62083ff..0811e86a3e7 100644
--- a/libs/langchain/langchain_classic/callbacks/streaming_aiter.py
+++ b/libs/langchain/langchain_classic/callbacks/streaming_aiter.py
@@ -39,11 +39,9 @@ class AsyncIteratorCallbackHandler(AsyncCallbackHandler):
         self.done.clear()
 
     @override
-    async def on_llm_new_token(
-        self, token: str | list[str | dict[str, Any]], **kwargs: Any
-    ) -> None:
+    async def on_llm_new_token(self, token: str, **kwargs: Any) -> None:
         if token is not None and token != "":
-            self.queue.put_nowait(str(token))
+            self.queue.put_nowait(token)
 
     @override
     async def on_llm_end(self, response: LLMResult, **kwargs: Any) -> None:
diff --git a/libs/langchain/langchain_classic/callbacks/streaming_aiter_final_only.py b/libs/langchain/langchain_classic/callbacks/streaming_aiter_final_only.py
index b9661639ca7..744475e6628 100644
--- a/libs/langchain/langchain_classic/callbacks/streaming_aiter_final_only.py
+++ b/libs/langchain/langchain_classic/callbacks/streaming_aiter_final_only.py
@@ -81,11 +81,9 @@ class AsyncFinalIteratorCallbackHandler(AsyncIteratorCallbackHandler):
             self.done.set()
 
     @override
-    async def on_llm_new_token(
-        self, token: str | list[str | dict[str, Any]], **kwargs: Any
-    ) -> None:
+    async def on_llm_new_token(self, token: str, **kwargs: Any) -> None:
         # Remember the last n tokens, where n = len(answer_prefix_tokens)
-        self.append_to_last_tokens(str(token))
+        self.append_to_last_tokens(token)
 
         # Check if the last n tokens match the answer_prefix_tokens list ...
         if self.check_if_answer_reached():
@@ -97,4 +95,4 @@ class AsyncFinalIteratorCallbackHandler(AsyncIteratorCallbackHandler):
 
         # If yes, then put tokens from now on
         if self.answer_reached:
-            self.queue.put_nowait(str(token))
+            self.queue.put_nowait(token)
diff --git a/libs/langchain/langchain_classic/callbacks/streaming_stdout_final_only.py b/libs/langchain/langchain_classic/callbacks/streaming_stdout_final_only.py
index 48af5a7b5f5..e8eee519b3e 100644
--- a/libs/langchain/langchain_classic/callbacks/streaming_stdout_final_only.py
+++ b/libs/langchain/langchain_classic/callbacks/streaming_stdout_final_only.py
@@ -76,12 +76,10 @@ class FinalStreamingStdOutCallbackHandler(StreamingStdOutCallbackHandler):
         self.answer_reached = False
 
     @override
-    def on_llm_new_token(
-        self, token: str | list[str | dict[str, Any]], **kwargs: Any
-    ) -> None:
+    def on_llm_new_token(self, token: str, **kwargs: Any) -> None:
         """Run on new LLM token. Only available when streaming is enabled."""
         # Remember the last n tokens, where n = len(answer_prefix_tokens)
-        self.append_to_last_tokens(str(token))
+        self.append_to_last_tokens(token)
 
         # Check if the last n tokens match the answer_prefix_tokens list ...
         if self.check_if_answer_reached():
@@ -94,5 +92,5 @@ class FinalStreamingStdOutCallbackHandler(StreamingStdOutCallbackHandler):
 
         # ... if yes, then print tokens from now on
         if self.answer_reached:
-            sys.stdout.write(str(token))
+            sys.stdout.write(token)
             sys.stdout.flush()
diff --git a/libs/langchain/tests/unit_tests/llms/test_fake_chat_model.py b/libs/langchain/tests/unit_tests/llms/test_fake_chat_model.py
index d467cab89d7..88cd91c3d13 100644
--- a/libs/langchain/tests/unit_tests/llms/test_fake_chat_model.py
+++ b/libs/langchain/tests/unit_tests/llms/test_fake_chat_model.py
@@ -173,7 +173,7 @@ async def test_callback_handlers() -> None:
         @override
         async def on_llm_new_token(
             self,
-            token: str | list[str | dict[str, Any]],
+            token: str,
             *,
             chunk: GenerationChunk | ChatGenerationChunk | None = None,
             run_id: UUID,
@@ -181,7 +181,7 @@ async def test_callback_handlers() -> None:
             tags: list[str] | None = None,
             **kwargs: Any,
         ) -> None:
-            self.store.append(str(token))
+            self.store.append(token)
 
     infinite_cycle = cycle(
         [