Remove check preventing passing non-declared config keys (#18276)

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libs/core/langchain_core/runnables/base.py

@@ -3995,16 +3995,6 @@ def __init__(
                 runnable with a custom type.
             **other_kwargs: Unpacked into the base class.
         """
-        config = config or {}
-        # config_specs contains the list of valid `configurable` keys
-        if configurable := config.get("configurable", None):
-            allowed_keys = set(s.id for s in bound.config_specs)
-            for key in configurable:
-                if key not in allowed_keys:
-                    raise ValueError(
-                        f"Configurable key '{key}' not found in runnable with"
-                        f" config keys: {allowed_keys}"
-                    )
         super().__init__(
             bound=bound,
             kwargs=kwargs or {},

libs/core/tests/unit_tests/runnables/test_runnable.py

@@ -1278,9 +1278,6 @@ def test_configurable_fields_example() -> None:
         },
     }
 
-    with pytest.raises(ValueError):
-        chain_configurable.with_config(configurable={"llm123": "chat"})
-
     assert (
         chain_configurable.with_config(configurable={"llm": "chat"}).invoke(
             {"name": "John"}