diff --git a/libs/langchain/langchain/schema/runnable/__init__.py b/libs/langchain/langchain/schema/runnable/__init__.py
index 0dbabd1579d..bae6aebb024 100644
--- a/libs/langchain/langchain/schema/runnable/__init__.py
+++ b/libs/langchain/langchain/schema/runnable/__init__.py
@@ -7,10 +7,13 @@ from langchain.schema.runnable.base import (
     RunnableWithFallbacks,
 )
 from langchain.schema.runnable.config import RunnableConfig
+from langchain.schema.runnable.locals import GetLocalVar, PutLocalVar
 from langchain.schema.runnable.passthrough import RunnablePassthrough
 from langchain.schema.runnable.router import RouterInput, RouterRunnable
 
 __all__ = [
+    "GetLocalVar",
+    "PutLocalVar",
     "RouterInput",
     "RouterRunnable",
     "Runnable",
diff --git a/libs/langchain/langchain/schema/runnable/base.py b/libs/langchain/langchain/schema/runnable/base.py
index 3f3e90ba27f..704a518cde8 100644
--- a/libs/langchain/langchain/schema/runnable/base.py
+++ b/libs/langchain/langchain/schema/runnable/base.py
@@ -238,7 +238,10 @@ class Runnable(Generic[Input, Output], ABC):
         return (
             config
             if isinstance(config, list)
-            else [deepcopy(config) if config is not None else {} for _ in range(length)]
+            else [
+                deepcopy(config) if config is not None else _empty_config()
+                for _ in range(length)
+            ]
         )
 
     def _call_with_config(
@@ -750,7 +753,7 @@ class RunnableSequence(Serializable, Runnable[Input, Output]):
         self, input: Input, config: Optional[RunnableConfig] = None
     ) -> Output:
         # setup callbacks
-        config = config or {}
+        config = config or _empty_config()
         callback_manager = _get_async_callback_manager(config)
         # start the root run
         run_manager = await callback_manager.on_chain_start(
@@ -896,7 +899,7 @@ class RunnableSequence(Serializable, Runnable[Input, Output]):
         self, input: Input, config: Optional[RunnableConfig] = None
     ) -> Iterator[Output]:
         # setup callbacks
-        config = config or {}
+        config = config or _empty_config()
         callback_manager = _get_callback_manager(config)
         # start the root run
         run_manager = callback_manager.on_chain_start(
@@ -963,7 +966,7 @@ class RunnableSequence(Serializable, Runnable[Input, Output]):
         self, input: Input, config: Optional[RunnableConfig] = None
     ) -> AsyncIterator[Output]:
         # setup callbacks
-        config = config or {}
+        config = config or _empty_config()
         callback_manager = _get_async_callback_manager(config)
         # start the root run
         run_manager = await callback_manager.on_chain_start(
diff --git a/libs/langchain/langchain/schema/runnable/locals.py b/libs/langchain/langchain/schema/runnable/locals.py
index cf51336dc9c..65e63507bc4 100644
--- a/libs/langchain/langchain/schema/runnable/locals.py
+++ b/libs/langchain/langchain/schema/runnable/locals.py
@@ -3,8 +3,9 @@ from __future__ import annotations
 from typing import Any, AsyncIterator, Dict, Iterator, Mapping, Optional, Union
 
 from langchain.load.serializable import Serializable
-from langchain.schema.runnable import Runnable, RunnableConfig, RunnablePassthrough
-from langchain.schema.runnable.base import Input, Output
+from langchain.schema.runnable.base import Input, Output, Runnable
+from langchain.schema.runnable.config import RunnableConfig
+from langchain.schema.runnable.passthrough import RunnablePassthrough
 
 
 class PutLocalVar(RunnablePassthrough):
@@ -27,7 +28,12 @@ class PutLocalVar(RunnablePassthrough):
             )
         if isinstance(self.key, str):
             config["_locals"][self.key] = input
-        elif isinstance(input, Mapping):
+        elif isinstance(self.key, Mapping):
+            if not isinstance(input, Mapping):
+                raise TypeError(
+                    f"Received key of type Mapping but input of type {type(input)}. "
+                    f"input is expected to be of type Mapping when key is Mapping."
+                )
             for input_key, put_key in self.key.items():
                 config["_locals"][put_key] = input[input_key]
         else:
@@ -44,17 +50,23 @@ class PutLocalVar(RunnablePassthrough):
                 "PutLocalVar should only be used in a RunnableSequence, and should "
                 "therefore always receive a non-null config."
             )
+        print(config)
         if isinstance(self.key, str):
             if self.key not in config["_locals"]:
                 config["_locals"][self.key] = input
             else:
                 config["_locals"][self.key] += input
-        elif isinstance(input, Mapping):
+        elif isinstance(self.key, Mapping):
+            if not isinstance(input, Mapping):
+                raise TypeError(
+                    f"Received key of type Mapping but input of type {type(input)}. "
+                    f"input is expected to be of type Mapping when key is Mapping."
+                )
             for input_key, put_key in self.key.items():
                 if put_key not in config["_locals"]:
-                    config["_locals"][put_key] = input
+                    config["_locals"][put_key] = input[input_key]
                 else:
-                    config["_locals"][put_key] += input
+                    config["_locals"][put_key] += input[input_key]
         else:
             raise TypeError(
                 f"`key` should be a string or Mapping[str, str], received type "
@@ -75,14 +87,14 @@ class PutLocalVar(RunnablePassthrough):
         self, input: Iterator[Input], config: RunnableConfig | None = None
     ) -> Iterator[Input]:
         for chunk in super().transform(input, config=config):
-            self._concat_put(input, config=config)
+            self._concat_put(chunk, config=config)
             yield chunk
 
     async def atransform(
         self, input: AsyncIterator[Input], config: RunnableConfig | None = None
     ) -> AsyncIterator[Input]:
         async for chunk in super().atransform(input, config=config):
-            self._concat_put(input, config=config)
+            self._concat_put(chunk, config=config)
             yield chunk