diff --git a/libs/langgraph/langgraph/pregel/remote.py b/libs/langgraph/langgraph/pregel/remote.py
index f7ae8c9b6..48a594066 100644
--- a/libs/langgraph/langgraph/pregel/remote.py
+++ b/libs/langgraph/langgraph/pregel/remote.py
@@ -67,10 +67,28 @@ def __init__(
         """
         self.name = name
         self.config = config
-        self.client = client or get_client(url=url, api_key=api_key, headers=headers)
-        self.sync_client = sync_client or get_sync_client(
-            url=url, api_key=api_key, headers=headers
-        )
+
+        if client is None and url is not None:
+            client = get_client(url=url, api_key=api_key, headers=headers)
+        self.client = client
+
+        if sync_client is None and url is not None:
+            sync_client = get_sync_client(url=url, api_key=api_key, headers=headers)
+        self.sync_client = sync_client
+
+    def _validate_client(self) -> LangGraphClient:
+        if self.client is None:
+            raise ValueError(
+                "Async client is not initialized: please provide `url` or `client` when initializing `RemoteGraph`."
+            )
+        return self.client
+
+    def _validate_sync_client(self) -> SyncLangGraphClient:
+        if self.sync_client is None:
+            raise ValueError(
+                "Sync client is not initialized: please provide `url` or `sync_client` when initializing `RemoteGraph`."
+            )
+        return self.sync_client
 
     def copy(self, update: dict[str, Any]) -> Self:
         attrs = {**self.__dict__, **update}
@@ -103,7 +121,8 @@ def get_graph(
         *,
         xray: Union[int, bool] = False,
     ) -> DrawableGraph:
-        graph = self.sync_client.assistants.get_graph(
+        sync_client = self._validate_sync_client()
+        graph = sync_client.assistants.get_graph(
             assistant_id=self.name,
             xray=xray,
         )
@@ -118,7 +137,8 @@ async def aget_graph(
         *,
         xray: Union[int, bool] = False,
     ) -> DrawableGraph:
-        graph = await self.client.assistants.get_graph(
+        client = self._validate_client()
+        graph = await client.assistants.get_graph(
             assistant_id=self.name,
             xray=xray,
         )
@@ -248,9 +268,10 @@ def _sanitize_obj(obj: Any) -> Any:
     def get_state(
         self, config: RunnableConfig, *, subgraphs: bool = False
     ) -> StateSnapshot:
+        sync_client = self._validate_sync_client()
         merged_config = merge_configs(self.config, config)
 
-        state = self.sync_client.threads.get_state(
+        state = sync_client.threads.get_state(
             thread_id=merged_config["configurable"]["thread_id"],
             checkpoint=self._get_checkpoint(merged_config),
             subgraphs=subgraphs,
@@ -260,9 +281,10 @@ def get_state(
     async def aget_state(
         self, config: RunnableConfig, *, subgraphs: bool = False
     ) -> StateSnapshot:
+        client = self._validate_client()
         merged_config = merge_configs(self.config, config)
 
-        state = await self.client.threads.get_state(
+        state = await client.threads.get_state(
             thread_id=merged_config["configurable"]["thread_id"],
             checkpoint=self._get_checkpoint(merged_config),
             subgraphs=subgraphs,
@@ -277,9 +299,10 @@ def get_state_history(
         before: Optional[RunnableConfig] = None,
         limit: Optional[int] = None,
     ) -> Iterator[StateSnapshot]:
+        sync_client = self._validate_sync_client()
         merged_config = merge_configs(self.config, config)
 
-        states = self.sync_client.threads.get_history(
+        states = sync_client.threads.get_history(
             thread_id=merged_config["configurable"]["thread_id"],
             limit=limit if limit else 10,
             before=self._get_checkpoint(before),
@@ -297,9 +320,10 @@ async def aget_state_history(
         before: Optional[RunnableConfig] = None,
         limit: Optional[int] = None,
     ) -> AsyncIterator[StateSnapshot]:
+        client = self._validate_client()
         merged_config = merge_configs(self.config, config)
 
-        states = await self.client.threads.get_history(
+        states = await client.threads.get_history(
             thread_id=merged_config["configurable"]["thread_id"],
             limit=limit if limit else 10,
             before=self._get_checkpoint(before),
@@ -315,9 +339,10 @@ def update_state(
         values: Optional[Union[dict[str, Any], Any]],
         as_node: Optional[str] = None,
     ) -> RunnableConfig:
+        sync_client = self._validate_sync_client()
         merged_config = merge_configs(self.config, config)
 
-        response: dict = self.sync_client.threads.update_state(  # type: ignore
+        response: dict = sync_client.threads.update_state(  # type: ignore
             thread_id=merged_config["configurable"]["thread_id"],
             values=values,
             as_node=as_node,
@@ -331,9 +356,10 @@ async def aupdate_state(
         values: Optional[Union[dict[str, Any], Any]],
         as_node: Optional[str] = None,
     ) -> RunnableConfig:
+        client = self._validate_client()
         merged_config = merge_configs(self.config, config)
 
-        response: dict = await self.client.threads.update_state(  # type: ignore
+        response: dict = await client.threads.update_state(  # type: ignore
             thread_id=merged_config["configurable"]["thread_id"],
             values=values,
             as_node=as_node,
@@ -382,11 +408,12 @@ def stream(
         interrupt_after: Optional[Union[All, Sequence[str]]] = None,
         subgraphs: bool = False,
     ) -> Iterator[Union[dict[str, Any], Any]]:
+        sync_client = self._validate_sync_client()
         merged_config = merge_configs(self.config, config)
         sanitized_config = self._sanitize_config(merged_config)
         stream_modes, req_updates, req_single = self._get_stream_modes(stream_mode)
 
-        for chunk in self.sync_client.runs.stream(
+        for chunk in sync_client.runs.stream(
             thread_id=sanitized_config["configurable"].get("thread_id"),
             assistant_id=self.name,
             input=input,
@@ -429,11 +456,12 @@ async def astream(
         interrupt_after: Optional[Union[All, Sequence[str]]] = None,
         subgraphs: bool = False,
     ) -> AsyncIterator[Union[dict[str, Any], Any]]:
+        client = self._validate_client()
         merged_config = merge_configs(self.config, config)
         sanitized_config = self._sanitize_config(merged_config)
         stream_modes, req_updates, req_single = self._get_stream_modes(stream_mode)
 
-        async for chunk in self.client.runs.stream(
+        async for chunk in client.runs.stream(
             thread_id=sanitized_config["configurable"].get("thread_id"),
             assistant_id=self.name,
             input=input,
@@ -490,10 +518,11 @@ def invoke(
         interrupt_before: Optional[Union[All, Sequence[str]]] = None,
         interrupt_after: Optional[Union[All, Sequence[str]]] = None,
     ) -> Union[dict[str, Any], Any]:
+        sync_client = self._validate_sync_client()
         merged_config = merge_configs(self.config, config)
         sanitized_config = self._sanitize_config(merged_config)
 
-        return self.sync_client.runs.wait(
+        return sync_client.runs.wait(
             thread_id=sanitized_config["configurable"].get("thread_id"),
             assistant_id=self.name,
             input=input,
@@ -511,10 +540,11 @@ async def ainvoke(
         interrupt_before: Optional[Union[All, Sequence[str]]] = None,
         interrupt_after: Optional[Union[All, Sequence[str]]] = None,
     ) -> Union[dict[str, Any], Any]:
+        client = self._validate_client()
         merged_config = merge_configs(self.config, config)
         sanitized_config = self._sanitize_config(merged_config)
 
-        return await self.client.runs.wait(
+        return await client.runs.wait(
             thread_id=sanitized_config["configurable"].get("thread_id"),
             assistant_id=self.name,
             input=input,